Recent videos for swine flu
Santa Swine Flu.mpg
01:37 - 3 days ago youtube.com
Kids across the state are standing in line for a chance to see Santa Clause, and make their Christmas wish list official. But while they ask Santa for gifts, they may be giving ...
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Billions in the trash ...
03:15 - 3 days ago youtube.com
Governments worldwide may have wasted billions of dollars stockpiling an ineffective flu drug. A study published in the British Medical Journal has found no evidence that ...
youtube.com
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H1N1 (Swine Flu)
05:48 - 7 months ago youtube.com
In this video, Dr. Joe Bresee with the CDC Influenza Division describes swine flu - its signs and symptoms, how it's transmitted, medicines to treat it, steps people can take ...
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Symptoms of H1N1 (Swine Flu)
03:25 - 7 months ago youtube.com
In this video, Dr. Joe Bresee, with CDC's Influenza Division, describes the symptoms of swine flu and warning signs to look for that indicate the need for urgent medical ...
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The Swine Flu Conspiracy
11:00 - 2 months ago youtube.com
Are you ready to roll up your sleeve?
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Understanding Swine Flu (Influenza A H1N1)
08:01 - 7 months ago fora.tv
Dr. Mary Young, assistant professor of medicine, discusses Influenza A H1N1 (swine flu), its symptoms, and steps that can be taken to prevent contracting or spreading the virus.
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Doctor Admits Vaccine Is More Deadly Than Swine Flu Itself & Will Not Give It ...
03:24 - 2 months ago youtube.com
The Swine Flu is an orchestrated attempt to spread fear and chaos into the population and to try to get people vaccinated, which everyone should know contains mercury that ...
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Swine Flu: H1N1
1 month ago cbsnews.com
Scott Pelley reports on the H1N1 flu - which is increasingly targeting young, healthy people - and how the government plans to fight the flu pandemic.
cbsnews.com
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8th case of swine flu confirmed
04:24 - 7 months ago cnn.com
The CDC confirms an eighth US case of swine flu in humans.
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Swine flu latest
01:31 - 1 month ago cnn.com
The CDC says more vaccine will be on the market soon, but notes the number of swine flu cases is also on the rise.
Monday, December 14, 2009
ഫിലുരെ ടോ Controle
KARACHI: The toll of swine flu patients in Sindh has risen to 24 since the month of June, said the Swine Flu Surveillance Cell incharge Dr Shakeel Malik ...
Swine flu scare fails to jolt health authorities The News International
Swine flu not a threat: DG Health Times of India
Every man for himself as swine flu scare spreads Daily Times
The Nation, Pakistan - Regional Times
all 30 news articles »
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Naples Daily News
Severity warning over low uptake of swine flu jab
The Standard - Mary Ann Benitez - 27 minutes ago
Fewer than 60 parents turned up on the first day of bookings for children to get human swine flu (H1N1) vaccinations, as the city braces for a second wave ...
La. has 40th swine flu death 2TheAdvocate
• CDC: Swine Flu Cases Continue To Decrease Consumer Affairs
Louisiana's 40th swine flu death was in NO area Shreveport Times
Examiner.com - Diamondback Online
all 231 news articles »
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Reuters
Swine flu's lesson: We're not ready for anything virulent
Chicago Daily Herald - Robert McCoppin - 1 hour ago
The H1N1 flu virus, also known as swine flu, turned out to be mild in most cases. But some experts say we dodged a bullet. An estimated 50 million people ...
Monday afternoon's swine flu clinic in West Sac expanded Daily Democrat
Swine flu vaccine available in Clatsop County Wednesday The Daily Astorian
Santa delivers H1N1 swine flu shots Norwalk Reflector
San Francisco Chronicle - Cowra Community News
all 2,810 news articles »
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SINDH TODAY
India's swine flu toll reaches 707
Sify - 3 hours ago
Seven swine flu deaths were reported in India Monday, taking the toll due to Influenza A (H1N1) virus to 707 so far, health authorities said here. ...
Swine flu death toll reaches 60 in Gujarat Press Trust of India
Two more swine flu deaths in Delhi Thaindian.com
19 more swine flu deaths reported in India, toll rises to 703 NetIndian
Bikya Masr - India Business Blog (blog)
all 36 news articles »
Email this story
Vancouverite
Swine flu vaccine opened to general public in Wis.
WKOW-TV.com - 54 minutes ago
(AP) - Anyone in Wisconsin who wants to get vaccinated against swine flu can now do so. State health officials said Monday that public health departments ...
Swine flu vaccination at all schools from Sat. Saudi Gazette
Swine Flu- A Panic Or Pandemic? Biomed Middle East
School student dies of swine flu, officials clueless Indian Express
HeraldNet - Arab News
all 61 news articles »
Email this story
Daily Mail
Girl sent home from hospital 'died of swine flu'
Telegraph.co.uk - 3 hours ago
A girl with suspected swine flu died a day after being sent home from hospital, her parents have said. Michelle Fernando, aged two years and three months, ...
Swine flu toddler died day after doctors 'told her parents she wasn't ill and ... Daily Mail
Bristol girl dies from suspected swine flu Bristol Evening Post
all 4 news articles »
Email this story
Swine flu's grip on city tightens
Times of India - Simran Virk - 3 hours ago
LUDHIANA: City is in the grip of swine flu, as with the decrease in temperature, the number of its patients is increasing rapidly. ...
Swine flu science update: 14 December 2009 SciDev.net
all 2 news articles »
Email this story
Call to ensure measures against swine flu
The News International - 20 hours ago
... to town health departments, on the orders of City Nazim Mustafa Kamal, to ensure proper measures against the possible outbreak of Swine Flu in the city. ...
Online Latest News (blog)
Another swine flu death in Chandigarh, 13 new cases
Thaindian.com - 14 hours ago
Chandigarh, Dec 14 (IANS) A 65-year-old man has become the latest victim of the swine flu virus in Chandigarh that has reported 13 new H1N1 cases, ...
Unrelenting flu: One dead, 16 test positive Times of India
Pinjore woman dies of swine flu Indian Express
Seven new swine flu cases in Chandigarh India Business Blog (blog)
PunjabNewsline.com - Times of India
all 42 news articles »
Email this story
Times LIVE
Swine flu fear spreads in India camp
-Photo by AFP MOHALI, India: India pace bowler Shanthakumaran Sreesanth had recovered from swine flu, but opening batsman Gautam Gambhir and two team ...
Flu-hit India is worried Daily News & Analysis
Gambhir diagnosed with swine flu The Press Association
Sreesanth suffering from swine flu Daily Times
Hindustan Times - Times LIVE
all 307 news articles »
Email
Swine flu scare fails to jolt health authorities The News International
Swine flu not a threat: DG Health Times of India
Every man for himself as swine flu scare spreads Daily Times
The Nation, Pakistan - Regional Times
all 30 news articles »
Email this story
Naples Daily News
Severity warning over low uptake of swine flu jab
The Standard - Mary Ann Benitez - 27 minutes ago
Fewer than 60 parents turned up on the first day of bookings for children to get human swine flu (H1N1) vaccinations, as the city braces for a second wave ...
La. has 40th swine flu death 2TheAdvocate
• CDC: Swine Flu Cases Continue To Decrease Consumer Affairs
Louisiana's 40th swine flu death was in NO area Shreveport Times
Examiner.com - Diamondback Online
all 231 news articles »
Email this story
Reuters
Swine flu's lesson: We're not ready for anything virulent
Chicago Daily Herald - Robert McCoppin - 1 hour ago
The H1N1 flu virus, also known as swine flu, turned out to be mild in most cases. But some experts say we dodged a bullet. An estimated 50 million people ...
Monday afternoon's swine flu clinic in West Sac expanded Daily Democrat
Swine flu vaccine available in Clatsop County Wednesday The Daily Astorian
Santa delivers H1N1 swine flu shots Norwalk Reflector
San Francisco Chronicle - Cowra Community News
all 2,810 news articles »
Email this story
SINDH TODAY
India's swine flu toll reaches 707
Sify - 3 hours ago
Seven swine flu deaths were reported in India Monday, taking the toll due to Influenza A (H1N1) virus to 707 so far, health authorities said here. ...
Swine flu death toll reaches 60 in Gujarat Press Trust of India
Two more swine flu deaths in Delhi Thaindian.com
19 more swine flu deaths reported in India, toll rises to 703 NetIndian
Bikya Masr - India Business Blog (blog)
all 36 news articles »
Email this story
Vancouverite
Swine flu vaccine opened to general public in Wis.
WKOW-TV.com - 54 minutes ago
(AP) - Anyone in Wisconsin who wants to get vaccinated against swine flu can now do so. State health officials said Monday that public health departments ...
Swine flu vaccination at all schools from Sat. Saudi Gazette
Swine Flu- A Panic Or Pandemic? Biomed Middle East
School student dies of swine flu, officials clueless Indian Express
HeraldNet - Arab News
all 61 news articles »
Email this story
Daily Mail
Girl sent home from hospital 'died of swine flu'
Telegraph.co.uk - 3 hours ago
A girl with suspected swine flu died a day after being sent home from hospital, her parents have said. Michelle Fernando, aged two years and three months, ...
Swine flu toddler died day after doctors 'told her parents she wasn't ill and ... Daily Mail
Bristol girl dies from suspected swine flu Bristol Evening Post
all 4 news articles »
Email this story
Swine flu's grip on city tightens
Times of India - Simran Virk - 3 hours ago
LUDHIANA: City is in the grip of swine flu, as with the decrease in temperature, the number of its patients is increasing rapidly. ...
Swine flu science update: 14 December 2009 SciDev.net
all 2 news articles »
Email this story
Call to ensure measures against swine flu
The News International - 20 hours ago
... to town health departments, on the orders of City Nazim Mustafa Kamal, to ensure proper measures against the possible outbreak of Swine Flu in the city. ...
Online Latest News (blog)
Another swine flu death in Chandigarh, 13 new cases
Thaindian.com - 14 hours ago
Chandigarh, Dec 14 (IANS) A 65-year-old man has become the latest victim of the swine flu virus in Chandigarh that has reported 13 new H1N1 cases, ...
Unrelenting flu: One dead, 16 test positive Times of India
Pinjore woman dies of swine flu Indian Express
Seven new swine flu cases in Chandigarh India Business Blog (blog)
PunjabNewsline.com - Times of India
all 42 news articles »
Email this story
Times LIVE
Swine flu fear spreads in India camp
-Photo by AFP MOHALI, India: India pace bowler Shanthakumaran Sreesanth had recovered from swine flu, but opening batsman Gautam Gambhir and two team ...
Flu-hit India is worried Daily News & Analysis
Gambhir diagnosed with swine flu The Press Association
Sreesanth suffering from swine flu Daily Times
Hindustan Times - Times LIVE
all 307 news articles »
വെല്ക്കം ടോ
Welcome to the world of Influenza
This site provides up-to-date information on Influenza, and the prevention of this infectious disease with a serious societal burden each year.As one of the world’s largest producers of Influenza vaccine Influvac®, Solvay Biologicals, a wholly owned subsidiary of Solvay Pharmaceuticals, is pleased to offer you this information.
We would like to emphasize that the information in this site is not intended to replace consultation with your physician. We strongly urge you to consult your physician or specialist if you suspect you have Influenza, or if you wonder whether you belong to the risk groups for Influenza and therefore should be routinely vaccinated against influenza.
This site provides up-to-date information on Influenza, and the prevention of this infectious disease with a serious societal burden each year.As one of the world’s largest producers of Influenza vaccine Influvac®, Solvay Biologicals, a wholly owned subsidiary of Solvay Pharmaceuticals, is pleased to offer you this information.
We would like to emphasize that the information in this site is not intended to replace consultation with your physician. We strongly urge you to consult your physician or specialist if you suspect you have Influenza, or if you wonder whether you belong to the risk groups for Influenza and therefore should be routinely vaccinated against influenza.
Swine Flu Outbreak
AmeriCares Sends Medical Aid to Mexico for Swine Flu Outbreak
Infection control masks, like these AmeriCares donated to a partner in Mexico, are effective against Swine Flu.
Mexico is in the midst of an outbreak of Influenza A, commonly known as Swine Flu. It has sickened more than 2,500 people and has been linked to 159 deaths. AmeriCares current aid to Mexico includes three shipments of medicines and supplies and we are preparing additional shipments to meet the health care needs of our partners.
AmeriCares recently sent two shipments to Mexico which included medicines, face masks for infection control and nutritional support for people who have been infected. The medicines included antibiotics to help fight the flu, fever and pain reducers to control symptoms and an inhalant to help people with breathing problems.
A third shipment to health care partners in Mexico is quickly being prepared for immediate shipment and will include additional face masks, gloves, IV fluids, vitamins, antibiotics, throat lozenges and other essential medicines and supplies to help treatment and prevention initiatives.
“AmeriCares is watching this Influenza A outbreak very carefully,” said Dr. Frank Bia, AmeriCares Medical Director and an expert in infectious diseases. “As Swine Flu infects more people, it can adapt and become more dangerous - like a hurricane picking up strength over warm water.”
Read Dr. Bia’s Q&A: What You Need to Know About the Swine Flu. The outbreak in Mexico City is particularly alarming because the dense population, combined with a lack of access to basic medicines can lead to a spike in infections.
“The current swine flu outbreak is the same strain, H1N1, as during the flu pandemic of 1918 when more than twenty million people died,” said Dr. Bia. “Even though we have advanced medicines today, the risk is still great in the developing world where health care is out of reach for so many.”
AmeriCares keeps infection control supplies, including face masks, gloves and hygiene items on reserve, enabling us to respond immediately to serious outbreaks like the Swine Flu in Mexico City.
Since 1989, AmeriCares has been working to help people in Mexico with critical medical needs. Medicines and medical supplies donated by AmeriCares have played a critical role in protecting and improving health outcomes.
--------------------------------------------------------------------------------
Infection control masks, like these AmeriCares donated to a partner in Mexico, are effective against Swine Flu.
Mexico is in the midst of an outbreak of Influenza A, commonly known as Swine Flu. It has sickened more than 2,500 people and has been linked to 159 deaths. AmeriCares current aid to Mexico includes three shipments of medicines and supplies and we are preparing additional shipments to meet the health care needs of our partners.
AmeriCares recently sent two shipments to Mexico which included medicines, face masks for infection control and nutritional support for people who have been infected. The medicines included antibiotics to help fight the flu, fever and pain reducers to control symptoms and an inhalant to help people with breathing problems.
A third shipment to health care partners in Mexico is quickly being prepared for immediate shipment and will include additional face masks, gloves, IV fluids, vitamins, antibiotics, throat lozenges and other essential medicines and supplies to help treatment and prevention initiatives.
“AmeriCares is watching this Influenza A outbreak very carefully,” said Dr. Frank Bia, AmeriCares Medical Director and an expert in infectious diseases. “As Swine Flu infects more people, it can adapt and become more dangerous - like a hurricane picking up strength over warm water.”
Read Dr. Bia’s Q&A: What You Need to Know About the Swine Flu. The outbreak in Mexico City is particularly alarming because the dense population, combined with a lack of access to basic medicines can lead to a spike in infections.
“The current swine flu outbreak is the same strain, H1N1, as during the flu pandemic of 1918 when more than twenty million people died,” said Dr. Bia. “Even though we have advanced medicines today, the risk is still great in the developing world where health care is out of reach for so many.”
AmeriCares keeps infection control supplies, including face masks, gloves and hygiene items on reserve, enabling us to respond immediately to serious outbreaks like the Swine Flu in Mexico City.
Since 1989, AmeriCares has been working to help people in Mexico with critical medical needs. Medicines and medical supplies donated by AmeriCares have played a critical role in protecting and improving health outcomes.
--------------------------------------------------------------------------------
Swine influenza
Swine influenza
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the influenza virus endemic in pigs. For the 2009 outbreak, see 2009 flu pandemic. For the virus causing the outbreak, see Pandemic H1N1/09 virus.
Influenza (Flu)
Types
Avian (A/H5N1 subtype) · Canine
Equine · Swine (A/H1N1 subtype)
Vaccines
2009 pandemic (Pandemrix)
ACAM-FLU-A · Fluzone · Influvac
Live attenuated (FluMist) · Optaflu
Treatment
Amantadine · Arbidol · Laninamivir
Oseltamivir · Peramivir · Rimantadine
Vitamin D · Zanamivir
Pandemics
2009 · 1968-1969 Hong Kong · 1918
Outbreaks
2008 West Bengal
2007 Bernard Matthews H5N1
2007 Australian equine
2006 H5N1 India · 1976 swine flu
See also
Flu season · Influenza evolution
Influenza research
Influenza-like illness
v • d • e
Electron microscope image of the reassorted H1N1 influenza virus photographed at the CDC Influenza Laboratory. The viruses are 80–120 nanometres in diameter.[1]Swine influenza (also called Pig influenza, swine flu, hog flu and pig flu) is an infection by any one of several types of swine influenza virus. Swine influenza virus (SIV) or S-OIV (swine-origin influenza virus) is any strain of the influenza family of viruses that is endemic in pigs.[2] As of 2009, the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2, and H2N3.
Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If transmission does cause human influenza, it is called zoonotic swine flu. People with regular exposure to pigs are at increased risk of swine flu infection. The meat of an infected animal poses no risk of infection when properly cooked.
During the mid-20th century, identification of influenza subtypes became possible, allowing accurate diagnosis of transmission to humans. Since then, only 50 such transmissions have been confirmed. These strains of swine flu rarely pass from human to human. Symptoms of zoonotic swine flu in humans are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort.
Contents [hide]
1 Classification
1.1 Influenza C
1.2 Influenza A
1.3 Surveillance
2 History
2.1 1918 pandemic in humans
2.2 1976 U.S. outbreak
2.3 1988 zoonosis
2.4 1998 US outbreak in swine
2.5 2007 Philippine outbreak in swine
2.6 2009 outbreak in humans
3 Transmission
3.1 Transmission between pigs
3.2 Transmission to humans
3.3 Interaction with avian H5N1 in pigs
4 Signs and symptoms
4.1 In swine
4.2 In humans
4.3 Diagnosis
5 Prevention
5.1 In swine
5.2 In humans
5.2.1 Vaccination
6 Treatment
6.1 In swine
6.2 In humans
7 See also
8 Notes
9 Further reading
10 External links
Classification
Of the three genera of influenza viruses that cause human flu, two also cause influenza in pigs, with influenza A being common in pigs and influenza C being rare.[3] Influenza B has not been reported in pigs. Within influenza A and influenza C, the strains found in pigs and humans are largely distinct, although because of reassortment there have been transfers of genes among strains crossing swine, avian, and human species boundaries.
Influenza C
Influenza C viruses infect both humans and pigs, but do not infect birds.[4] Transmission between pigs and humans have occurred in the past.[5] For example, influenza C caused small outbreaks of a mild form of influenza amongst children in Japan[6] and California.[6] Because of its limited host range and the lack of genetic diversity in influenza C, this form of influenza does not cause pandemics in humans.[7]
Influenza A
Swine influenza is known to be caused by influenza A subtypes H1N1,[8] H1N2,[8] H2N3,[9] H3N1,[10] and H3N2.[8] In pigs, three influenza A virus subtypes (H1N1, H1N2, and H3N2) are the most common strains worldwide.[11] In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.[12]
Surveillance
Although there is no formal national surveillance system in the United States to determine what viruses are circulating in pigs,[13] there is an informal surveillance network in the United States that is part of a world surveillance network.
Veterinary medical pathologist, Tracey McNamara, set up a national disease surveillance system in zoos because the zoos do active disease surveillance and many of the exotic animals housed there have broad susceptibilities. Many species fall below the radar of any federal agencies (including dogs, cats, pet prairie dogs, zoo animals, and urban wildlife), even though they may be important in the early detection of human disease outbreaks.[14] [15]
History
Swine influenza was first proposed to be a disease related to human influenza during the 1918 flu pandemic, when pigs became sick at the same time as humans.[16] The first identification of an influenza virus as a cause of disease in pigs occurred about ten years later, in 1930.[17] For the following 60 years, swine influenza strains were almost exclusively H1N1. Then, between 1997 and 2002, new strains of three different subtypes and five different genotypes emerged as causes of influenza among pigs in North America. In 1997–1998, H3N2 strains emerged. These strains, which include genes derived by reassortment from human, swine and avian viruses, have become a major cause of swine influenza in North America. Reassortment between H1N1 and H3N2 produced H1N2. In 1999 in Canada, a strain of H4N6 crossed the species barrier from birds to pigs, but was contained on a single farm.[17]
The H1N1 form of swine flu is one of the descendants of the strain that caused the 1918 flu pandemic.[18][19] As well as persisting in pigs, the descendants of the 1918 virus have also circulated in humans through the 20th century, contributing to the normal seasonal epidemics of influenza.[19] However, direct transmission from pigs to humans is rare, with only 12 cases in the U.S. since 2005.[20] Nevertheless, the retention of influenza strains in pigs after these strains have disappeared from the human population might make pigs a reservoir where influenza viruses could persist, later emerging to reinfect humans once human immunity to these strains has waned.[21]
Swine flu has been reported numerous times as a zoonosis in humans, usually with limited distribution, rarely with a widespread distribution. Outbreaks in swine are common and cause significant economic losses in industry, primarily by causing stunting and extended time to market. For example, this disease costs the British meat industry about £65 million every year.[22]
1918 pandemic in humans
The 1918 flu pandemic in humans was associated with H1N1 and influenza appearing in pigs;[19] this may reflect a zoonosis either from swine to humans, or from humans to swine. Although it is not certain in which direction the virus was transferred, some evidence suggests that, in this case, pigs caught the disease from humans.[16] For instance, swine influenza was only noted as a new disease of pigs in 1918, after the first large outbreaks of influenza amongst people.[16] Although a recent phylogenetic analysis of more recent strains of influenza in humans, birds, and swine suggests that the 1918 outbreak in humans followed a reassortment event within a mammal,[23] the exact origin of the 1918 strain remains elusive.[24] It is estimated that anywhere from 50 to 100 million people were killed worldwide.[19][25]
1976 U.S. outbreak
Main article: 1976 swine flu outbreak
On February 5, 1976, in the United States an army recruit at Fort Dix said he felt tired and weak. He died the next day and four of his fellow soldiers were later hospitalized. Two weeks after his death, health officials announced that the cause of death was a new strain of swine flu. The strain, a variant of H1N1, is known as A/New Jersey/1976 (H1N1). It was detected only from January 19 to February 9 and did not spread beyond Fort Dix.[26]
President Ford receives swine flu vaccinationThis new strain appeared to be closely related to the strain involved in the 1918 flu pandemic. Moreover, the ensuing increased surveillance uncovered another strain in circulation in the U.S.: A/Victoria/75 (H3N2) spread simultaneously, also caused illness, and persisted until March.[26] Alarmed public-health officials decided action must be taken to head off another major pandemic, and urged President Gerald Ford that every person in the U.S. be vaccinated for the disease.[27]
The vaccination program was plagued by delays and public relations problems.[28] On October 1, 1976, immunizations began and three senior citizens died soon after receiving their injections. This resulted in a media outcry that linked these deaths to the immunizations, despite the lack of any proof that the vaccine was the cause. According to science writer Patrick Di Justo, however, by the time the truth was known—that the deaths were not proven to be related to the vaccine—it was too late. "The government had long feared mass panic about swine flu—now they feared mass panic about the swine flu vaccinations." This became a strong setback to the program.[29]
There were reports of Guillain-Barré syndrome, a paralyzing neuromuscular disorder, affecting some people who had received swine flu immunizations. Although if a link exists is still not clear, this syndrome may be a rare side-effect of influenza vaccines. As a result, Di Justo writes that "the public refused to trust a government-operated health program that killed old people and crippled young people." In total, 48,161,019 Americans, or just over 22% of the population, had been immunized by the time the National Influenza Immunization Program (NIIP) was effectively halted on December 16, 1976.[30] [31]
Overall, there were 1098 cases of Guillain-Barré Syndrome (GBS) recorded nationwide by CDC surveillance, 532 of which occurred after vaccination and 543 before vaccination.[32] There are about one to two cases of GBS per 100,000 people every year, whether or not people have been vaccinated.[33] The vaccination program seems to have increased this normal risk of developing GBS by about to one extra case per 100,000 vaccinations.[33] The CDC states that most studies on modern influenza vaccines have seen no link with GBS,[33][34][35] Although one review gives an incidence of about one case per million vaccinations.[36]
1988 zoonosis
In September 1988, a swine flu virus killed one woman and infected others. 32-year old Barbara Ann Wieners was eight months pregnant when she and her husband, Ed, became ill after visiting the hog barn at a county fair in Walworth County, Wisconsin. Barbara died eight days later, after developing pneumonia.[37] The only pathogen identified was an H1N1 strain of swine influenza virus.[38] Doctors were able to induce labor and deliver a healthy daughter before she died. Her husband recovered from his symptoms.
Influenza-like illness (ILI) was reportedly widespread among the pigs exhibited at the fair. Of the 25 swine exhibitors aged 9 to 19 at the fair, 19 tested positive for antibodies to SIV, but no serious illnesses were seen. The virus was able to spread between people, since 1-3 health care personnel who had cared for the pregnant woman developed mild influenza-like illnesses, and antibody tests suggested that they had been infected with swine flu. However, there was no community outbreak.[39][40]
1998 US outbreak in swine
In 1998, swine flu was found in pigs in four U.S. states. Within a year, it had spread through pig populations across the United States. Scientists found that this virus had originated in pigs as a recombinant form of flu strains from birds and humans. This outbreak confirmed that pigs can serve as a crucible where novel influenza viruses emerge as a result of the reassortment of genes from different strains.[41][42][43] Genetic components of these 1998 triple-hybrid stains would later form six out of the eight viral gene segments in the 2009 flu outbreak.[44][45][46][47][48]
2007 Philippine outbreak in swine
Please help improve this article by expanding it. Further information might be found on the talk page. (April 2009)
On August 20, 2007 Department of Agriculture officers investigated the outbreak (epizootic) of swine flu in Nueva Ecija and Central Luzon, Philippines. The mortality rate is less than 10% for swine flu, unless there are complications like hog cholera. On July 27, 2007, the Philippine National Meat Inspection Service (NMIS) raised a hog cholera "red alert" warning over Metro Manila and 5 regions of Luzon after the disease spread to backyard pig farms in Bulacan and Pampanga, even if these tested negative for the swine flu virus.[49][50]
2009 outbreak in humans
Main article: 2009 flu pandemic
The H1N1 viral strain implicated in the 2009 flu pandemic among humans often is called "swine flu" because initial testing showed many of the genes in the virus were similar to influenza viruses normally occurring in North American swine.[51] Further research has shown that three-quarters or six out of the eight gene segments of the 2009 virus arose from the 1998 North American swine flu strains which emerged from the first-ever reported triple-hybrid virus of 1998.[44][44][47][47][48]
In late April, Margaret Chan, the World Health Organization's director-general, declared a "public health emergency of international concern" under the rules of the WHO's new International Health Regulations when the first two cases of the H1N1 virus were reported in the United States, followed by hundreds of cases in Mexico.[52][53] Following the initial cases in the USA and Mexico, on May 2, 2009, it was reported in pigs at a farm in Alberta, Canada, with a link to the outbreak in Mexico. The pigs are suspected to have caught this new strain of virus from a farm worker who recently returned from Mexico, then showed symptoms of an influenza-like illness.[54] These are probable cases, pending confirmation by laboratory testing.
The new strain was initially described as an apparent reassortment of at least four strains of influenza A virus subtype H1N1, including one strain endemic in humans, one endemic in birds, and two endemic in swine.[51] Subsequent analysis suggested it was a reassortment of just two strains, both found in swine.[55] Although initial reports identified the new strain as swine influenza (i.e., a zoonosis originating in swine), its genetic origin was only later revealed to have been mostly a descendant of the triple-reassortment virus which emerged in factory farms in the United States in 1998.[44][44][47][47][48] Several countries took precautionary measures to reduce the chances for a global pandemic of the disease.[56] The 2009 swine flu has been compared to other similar types of influenza virus in terms of mortality: "in the US it appears that for every 1000 people who get infected, about 40 people need admission to hospital and about one person dies."[57] There are fears that swine flu will become a major global pandemic at the end of the year (coinciding with the Northern Hemisphere winter months), with many countries planning major vaccination campaigns.[58]
Transmission
Transmission between pigs
Influenza is quite common in pigs, with about half of breeding pigs having been exposed to the virus in the US.[59] Antibodies to the virus are also common in pigs in other countries.[59]
The main route of transmission is through direct contact between infected and uninfected animals.[11] These close contacts are particularly common during animal transport. Intensive farming may also increase the risk of transmission, as the pigs are raised in very close proximity to each other.[60][61] The direct transfer of the virus probably occurs either by pigs touching noses, or through dried mucus. Airborne transmission through the aerosols produced by pigs coughing or sneezing are also an important means of infection.[11] The virus usually spreads quickly through a herd, infecting all the pigs within just a few days.[2] Transmission may also occur through wild animals, such as wild boar, which can spread the disease between farms.[62]
Transmission to humans
People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur.[63] Vaccination of these workers against influenza and surveillance for new influenza strains among this population may therefore be an important public health measure.[64] Transmission of influenza from swine to humans who work with swine was documented in a small surveillance study performed in 2004 at the University of Iowa.[65] This study among others forms the basis of a recommendation that people whose jobs involve handling poultry and swine be the focus of increased public health surveillance.[63] Other professions at particular risk of infection are veterinarians and meat processing workers, although the risk of infection for both of these groups is lower than that of farm workers.[66]
Interaction with avian H5N1 in pigs
Pigs are unusual as they can be infected with influenza strains that usually infect three different species: pigs, birds and humans.[67] This makes pigs a host where influenza viruses might exchange genes, producing new and dangerous strains.[67] Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam, increasing fears of the emergence of new variant strains.[68] H3N2 evolved from H2N2 by antigenic shift.[69] In August 2004, researchers in China found H5N1 in pigs.[70]
Main symptoms of swine flu in swine.[2]These H5N1 infections may be quite common: in a survey of 10 apparently healthy pigs housed near poultry farms in West Java, where avian flu had broken out, five of the pig samples contained the H5N1 virus. The Indonesian government has since found similar results in the same region. Additional tests of 150 pigs outside the area were negative.[71][72]
Signs and symptoms
In swine
In pigs influenza infection produces fever, lethargy, sneezing, coughing, difficulty breathing and decreased appetite.[11] In some cases the infection can cause abortion. Although mortality is usually low (around 1–4%),[2] the virus can produce weight loss and poor growth, causing economic loss to farmers.[11] Infected pigs can lose up to 12 pounds of body weight over a 3 to 4 week period.[11]
In humans
Main symptoms of swine flu in humans[73]Direct transmission of a swine flu virus from pigs to humans is occasionally possible (called zoonotic swine flu). In all, 50 cases are known to have occurred since the first report in medical literature in 1958, which have resulted in a total of six deaths.[74] Of these six people, one was pregnant, one had leukemia, one had Hodgkin disease and two were known to be previously healthy.[74] Despite these apparently low numbers of infections, the true rate of infection may be higher, since most cases only cause a very mild disease, and will probably never be reported or diagnosed.[74]
In this video, Dr. Joe Bresee, with CDC's Influenza Division, describes the symptoms of swine flu and warning signs to look for that indicate the need for urgent medical attention.
See also: See this video with subtitles on YouTube [1]According to the Centers for Disease Control and Prevention (CDC), in humans the symptoms of the 2009 "swine flu" H1N1 virus are similar to those of influenza and of influenza-like illness in general. Symptoms include fever, cough, sore throat, body aches, headache, chills and fatigue. The 2009 outbreak has shown an increased percentage of patients reporting diarrhea and vomiting.[75] The 2009 H1N1 virus is not zoonotic swine flu, as it is not transmitted from pigs to humans, but from person to person.
Because these symptoms are not specific to swine flu, a differential diagnosis of probable swine flu requires not only symptoms but also a high likelihood of swine flu due to the person's recent history. For example, during the 2009 swine flu outbreak in the United States, CDC advised physicians to "consider swine influenza infection in the differential diagnosis of patients with acute febrile respiratory illness who have either been in contact with persons with confirmed swine flu, or who were in one of the five U.S. states that have reported swine flu cases or in Mexico during the 7 days preceding their illness onset."[76] A diagnosis of confirmed swine flu requires laboratory testing of a respiratory sample (a simple nose and throat swab).[76]
The most common cause of death is respiratory failure. Other causes of death are pneumonia (leading to sepsis)[77], high fever (leading to neurological problems), dehydration (from excessive vomiting and diarrhea) and electrolyte imbalance. Fatalities are more likely in young children and the elderly.
Diagnosis
Thermal scanning of passengers arriving at Singapore Changi airport.The CDC recommends real time RT-PCR as the method of choice for diagnosing H1N1.[78] This method allows a specific diagnosis of novel influenza (H1N1) as opposed to seasonal influenza. Near-patient point of care tests are in development.[79]
Prevention
Prevention of swine influenza has three components: prevention in swine, prevention of transmission to humans, and prevention of its spread among humans.
In swine
Methods of preventing the spread of influenza among swine include facility management, herd management, and vaccination (ATCvet code: QI09AA03). Because much of the illness and death associated with swine flu involves secondary infection by other pathogens, control strategies that rely on vaccination may be insufficient.
Control of swine influenza by vaccination has become more difficult in recent decades, as the evolution of the virus has resulted in inconsistent responses to traditional vaccines. Standard commercial swine flu vaccines are effective in controlling the infection when the virus strains match enough to have significant cross-protection, and custom (autogenous) vaccines made from the specific viruses isolated are created and used in the more difficult cases.[80][81] Present vaccination strategies for SIV control and prevention in swine farms typically include the use of one of several bivalent SIV vaccines commercially available in the United States. Of the 97 recent H3N2 isolates examined, only 41 isolates had strong serologic cross-reactions with antiserum to three commercial SIV vaccines. Since the protective ability of influenza vaccines depends primarily on the closeness of the match between the vaccine virus and the epidemic virus, the presence of nonreactive H3N2 SIV variants suggests that current commercial vaccines might not effectively protect pigs from infection with a majority of H3N2 viruses.[82][83] The United States Department of Agriculture researchers say that while pig vaccination keeps pigs from getting sick, it does not block infection or shedding of the virus.[84]
Facility management includes using disinfectants and ambient temperature to control virus in the environment. The virus is unlikely to survive outside living cells for more than two weeks, except in cold (but above freezing) conditions, and it is readily inactivated by disinfectants.[2] Herd management includes not adding pigs carrying influenza to herds that have not been exposed to the virus. The virus survives in healthy carrier pigs for up to 3 months and can be recovered from them between outbreaks. Carrier pigs are usually responsible for the introduction of SIV into previously uninfected herds and countries, so new animals should be quarantined.[59] After an outbreak, as immunity in exposed pigs wanes, new outbreaks of the same strain can occur.[2]
In humans
Prevention of pig to human transmission
Swine can be infected by both avian and human influenza strains of influenza, and therefore are hosts where the antigenic shifts can occur that create new influenza strains.
The transmission from swine to human is believed to occur mainly in swine farms where farmers are in close contact with live pigs. Although strains of swine influenza are usually not able to infect humans this may occasionally happen, so farmers and veterinarians are encouraged to use a face mask when dealing with infected animals. The use of vaccines on swine to prevent their infection is a major method of limiting swine to human transmission. Risk factors that may contribute to swine-to-human transmission include smoking and not wearing gloves when working with sick animals.[85]
Prevention of human to human transmission
Influenza spreads between humans through coughing or sneezing and people touching something with the virus on it and then touching their own nose or mouth.[86] Swine flu cannot be spread by pork products, since the virus is not transmitted through food.[86] The swine flu in humans is most contagious during the first five days of the illness although some people, most commonly children, can remain contagious for up to ten days. Diagnosis can be made by sending a specimen, collected during the first five days for analysis.[87]
Thermal imaging camera & screen, photographed in an airport terminal in Greece. Thermal imaging can detect elevated body temperature, one of the signs of the virus N1H1 (Swine influenza).Recommendations to prevent spread of the virus among humans include using standard infection control against influenza. This includes frequent washing of hands with soap and water or with alcohol-based hand sanitizers, especially after being out in public.[88] Chance of transmission is also reduced by disinfecting household surfaces, which can be done effectively with a diluted chlorine bleach solution.[89]
Experts agree that hand-washing can help prevent viral infections, including ordinary influenza and the swine flu virus. Also avoiding touching eyes, nose and mouth with hands prevents flu.[90] Influenza can spread in coughs or sneezes, but an increasing body of evidence shows small droplets containing the virus can linger on tabletops, telephones and other surfaces and be transferred via the fingers to the mouth, nose or eyes. Alcohol-based gel or foam hand sanitizers work well to destroy viruses and bacteria. Anyone with flu-like symptoms such as a sudden fever, cough or muscle aches should stay away from work or public transportation and should contact a doctor for advice.[91]
Social distancing is another tactic. It means staying away from other people who might be infected and can include avoiding large gatherings, spreading out a little at work, or perhaps staying home and lying low if an infection is spreading in a community. Public health and other responsible authorities have action plans which may request or require social distancing actions depending on the severity of the outbreak.
Vaccination
Main article: 2009 flu pandemic vaccine
Vaccines are available for different kinds of swine flu. The U.S. Food and Drug Administration (FDA) approved the new swine flu vaccine for use in the United States on September 15, 2009.[92] Studies by the National Institutes of Health (NIH), show that a single dose creates enough antibodies to protect against the virus within about 10 days.[92]
Treatment
In swine
As swine influenza is rarely fatal to pigs, little treatment beyond rest and supportive care is required.[59] Instead veterinary efforts are focused on preventing the spread of the virus throughout the farm, or to other farms.[11] Vaccination and animal management techniques are most important in these efforts. Antibiotics are also used to treat this disease, which although they have no effect against the influenza virus, do help prevent bacterial pneumonia and other secondary infections in influenza-weakened herds.[59]
In humans
If a person becomes sick with swine flu, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). Beside antivirals, supportive care at home or in hospital, focuses on controlling fevers, relieving pain and maintaining fluid balance, as well as identifying and treating any secondary infections or other medical problems. The U.S. Centers for Disease Control and Prevention recommends the use of Tamiflu (oseltamivir) or Relenza (zanamivir) for the treatment and/or prevention of infection with swine influenza viruses; however, the majority of people infected with the virus make a full recovery without requiring medical attention or antiviral drugs.[93] The virus isolates in the 2009 outbreak have been found resistant to amantadine and rimantadine.[94]
In the U.S., on April 27, 2009, the FDA issued Emergency Use Authorizations to make available Relenza and Tamiflu antiviral drugs to treat the swine influenza virus in cases for which they are currently unapproved. The agency issued these EUAs to allow treatment of patients younger than the current approval allows and to allow the widespread distribution of the drugs, including by non-licensed volunteers.[95]
See also
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Dog flu
Horse flu
Pandemic
Infectious disease
List of epidemics
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This article is about the influenza virus endemic in pigs. For the 2009 outbreak, see 2009 flu pandemic. For the virus causing the outbreak, see Pandemic H1N1/09 virus.
Influenza (Flu)
Types
Avian (A/H5N1 subtype) · Canine
Equine · Swine (A/H1N1 subtype)
Vaccines
2009 pandemic (Pandemrix)
ACAM-FLU-A · Fluzone · Influvac
Live attenuated (FluMist) · Optaflu
Treatment
Amantadine · Arbidol · Laninamivir
Oseltamivir · Peramivir · Rimantadine
Vitamin D · Zanamivir
Pandemics
2009 · 1968-1969 Hong Kong · 1918
Outbreaks
2008 West Bengal
2007 Bernard Matthews H5N1
2007 Australian equine
2006 H5N1 India · 1976 swine flu
See also
Flu season · Influenza evolution
Influenza research
Influenza-like illness
v • d • e
Electron microscope image of the reassorted H1N1 influenza virus photographed at the CDC Influenza Laboratory. The viruses are 80–120 nanometres in diameter.[1]Swine influenza (also called Pig influenza, swine flu, hog flu and pig flu) is an infection by any one of several types of swine influenza virus. Swine influenza virus (SIV) or S-OIV (swine-origin influenza virus) is any strain of the influenza family of viruses that is endemic in pigs.[2] As of 2009, the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2, and H2N3.
Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If transmission does cause human influenza, it is called zoonotic swine flu. People with regular exposure to pigs are at increased risk of swine flu infection. The meat of an infected animal poses no risk of infection when properly cooked.
During the mid-20th century, identification of influenza subtypes became possible, allowing accurate diagnosis of transmission to humans. Since then, only 50 such transmissions have been confirmed. These strains of swine flu rarely pass from human to human. Symptoms of zoonotic swine flu in humans are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort.
Contents [hide]
1 Classification
1.1 Influenza C
1.2 Influenza A
1.3 Surveillance
2 History
2.1 1918 pandemic in humans
2.2 1976 U.S. outbreak
2.3 1988 zoonosis
2.4 1998 US outbreak in swine
2.5 2007 Philippine outbreak in swine
2.6 2009 outbreak in humans
3 Transmission
3.1 Transmission between pigs
3.2 Transmission to humans
3.3 Interaction with avian H5N1 in pigs
4 Signs and symptoms
4.1 In swine
4.2 In humans
4.3 Diagnosis
5 Prevention
5.1 In swine
5.2 In humans
5.2.1 Vaccination
6 Treatment
6.1 In swine
6.2 In humans
7 See also
8 Notes
9 Further reading
10 External links
Classification
Of the three genera of influenza viruses that cause human flu, two also cause influenza in pigs, with influenza A being common in pigs and influenza C being rare.[3] Influenza B has not been reported in pigs. Within influenza A and influenza C, the strains found in pigs and humans are largely distinct, although because of reassortment there have been transfers of genes among strains crossing swine, avian, and human species boundaries.
Influenza C
Influenza C viruses infect both humans and pigs, but do not infect birds.[4] Transmission between pigs and humans have occurred in the past.[5] For example, influenza C caused small outbreaks of a mild form of influenza amongst children in Japan[6] and California.[6] Because of its limited host range and the lack of genetic diversity in influenza C, this form of influenza does not cause pandemics in humans.[7]
Influenza A
Swine influenza is known to be caused by influenza A subtypes H1N1,[8] H1N2,[8] H2N3,[9] H3N1,[10] and H3N2.[8] In pigs, three influenza A virus subtypes (H1N1, H1N2, and H3N2) are the most common strains worldwide.[11] In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.[12]
Surveillance
Although there is no formal national surveillance system in the United States to determine what viruses are circulating in pigs,[13] there is an informal surveillance network in the United States that is part of a world surveillance network.
Veterinary medical pathologist, Tracey McNamara, set up a national disease surveillance system in zoos because the zoos do active disease surveillance and many of the exotic animals housed there have broad susceptibilities. Many species fall below the radar of any federal agencies (including dogs, cats, pet prairie dogs, zoo animals, and urban wildlife), even though they may be important in the early detection of human disease outbreaks.[14] [15]
History
Swine influenza was first proposed to be a disease related to human influenza during the 1918 flu pandemic, when pigs became sick at the same time as humans.[16] The first identification of an influenza virus as a cause of disease in pigs occurred about ten years later, in 1930.[17] For the following 60 years, swine influenza strains were almost exclusively H1N1. Then, between 1997 and 2002, new strains of three different subtypes and five different genotypes emerged as causes of influenza among pigs in North America. In 1997–1998, H3N2 strains emerged. These strains, which include genes derived by reassortment from human, swine and avian viruses, have become a major cause of swine influenza in North America. Reassortment between H1N1 and H3N2 produced H1N2. In 1999 in Canada, a strain of H4N6 crossed the species barrier from birds to pigs, but was contained on a single farm.[17]
The H1N1 form of swine flu is one of the descendants of the strain that caused the 1918 flu pandemic.[18][19] As well as persisting in pigs, the descendants of the 1918 virus have also circulated in humans through the 20th century, contributing to the normal seasonal epidemics of influenza.[19] However, direct transmission from pigs to humans is rare, with only 12 cases in the U.S. since 2005.[20] Nevertheless, the retention of influenza strains in pigs after these strains have disappeared from the human population might make pigs a reservoir where influenza viruses could persist, later emerging to reinfect humans once human immunity to these strains has waned.[21]
Swine flu has been reported numerous times as a zoonosis in humans, usually with limited distribution, rarely with a widespread distribution. Outbreaks in swine are common and cause significant economic losses in industry, primarily by causing stunting and extended time to market. For example, this disease costs the British meat industry about £65 million every year.[22]
1918 pandemic in humans
The 1918 flu pandemic in humans was associated with H1N1 and influenza appearing in pigs;[19] this may reflect a zoonosis either from swine to humans, or from humans to swine. Although it is not certain in which direction the virus was transferred, some evidence suggests that, in this case, pigs caught the disease from humans.[16] For instance, swine influenza was only noted as a new disease of pigs in 1918, after the first large outbreaks of influenza amongst people.[16] Although a recent phylogenetic analysis of more recent strains of influenza in humans, birds, and swine suggests that the 1918 outbreak in humans followed a reassortment event within a mammal,[23] the exact origin of the 1918 strain remains elusive.[24] It is estimated that anywhere from 50 to 100 million people were killed worldwide.[19][25]
1976 U.S. outbreak
Main article: 1976 swine flu outbreak
On February 5, 1976, in the United States an army recruit at Fort Dix said he felt tired and weak. He died the next day and four of his fellow soldiers were later hospitalized. Two weeks after his death, health officials announced that the cause of death was a new strain of swine flu. The strain, a variant of H1N1, is known as A/New Jersey/1976 (H1N1). It was detected only from January 19 to February 9 and did not spread beyond Fort Dix.[26]
President Ford receives swine flu vaccinationThis new strain appeared to be closely related to the strain involved in the 1918 flu pandemic. Moreover, the ensuing increased surveillance uncovered another strain in circulation in the U.S.: A/Victoria/75 (H3N2) spread simultaneously, also caused illness, and persisted until March.[26] Alarmed public-health officials decided action must be taken to head off another major pandemic, and urged President Gerald Ford that every person in the U.S. be vaccinated for the disease.[27]
The vaccination program was plagued by delays and public relations problems.[28] On October 1, 1976, immunizations began and three senior citizens died soon after receiving their injections. This resulted in a media outcry that linked these deaths to the immunizations, despite the lack of any proof that the vaccine was the cause. According to science writer Patrick Di Justo, however, by the time the truth was known—that the deaths were not proven to be related to the vaccine—it was too late. "The government had long feared mass panic about swine flu—now they feared mass panic about the swine flu vaccinations." This became a strong setback to the program.[29]
There were reports of Guillain-Barré syndrome, a paralyzing neuromuscular disorder, affecting some people who had received swine flu immunizations. Although if a link exists is still not clear, this syndrome may be a rare side-effect of influenza vaccines. As a result, Di Justo writes that "the public refused to trust a government-operated health program that killed old people and crippled young people." In total, 48,161,019 Americans, or just over 22% of the population, had been immunized by the time the National Influenza Immunization Program (NIIP) was effectively halted on December 16, 1976.[30] [31]
Overall, there were 1098 cases of Guillain-Barré Syndrome (GBS) recorded nationwide by CDC surveillance, 532 of which occurred after vaccination and 543 before vaccination.[32] There are about one to two cases of GBS per 100,000 people every year, whether or not people have been vaccinated.[33] The vaccination program seems to have increased this normal risk of developing GBS by about to one extra case per 100,000 vaccinations.[33] The CDC states that most studies on modern influenza vaccines have seen no link with GBS,[33][34][35] Although one review gives an incidence of about one case per million vaccinations.[36]
1988 zoonosis
In September 1988, a swine flu virus killed one woman and infected others. 32-year old Barbara Ann Wieners was eight months pregnant when she and her husband, Ed, became ill after visiting the hog barn at a county fair in Walworth County, Wisconsin. Barbara died eight days later, after developing pneumonia.[37] The only pathogen identified was an H1N1 strain of swine influenza virus.[38] Doctors were able to induce labor and deliver a healthy daughter before she died. Her husband recovered from his symptoms.
Influenza-like illness (ILI) was reportedly widespread among the pigs exhibited at the fair. Of the 25 swine exhibitors aged 9 to 19 at the fair, 19 tested positive for antibodies to SIV, but no serious illnesses were seen. The virus was able to spread between people, since 1-3 health care personnel who had cared for the pregnant woman developed mild influenza-like illnesses, and antibody tests suggested that they had been infected with swine flu. However, there was no community outbreak.[39][40]
1998 US outbreak in swine
In 1998, swine flu was found in pigs in four U.S. states. Within a year, it had spread through pig populations across the United States. Scientists found that this virus had originated in pigs as a recombinant form of flu strains from birds and humans. This outbreak confirmed that pigs can serve as a crucible where novel influenza viruses emerge as a result of the reassortment of genes from different strains.[41][42][43] Genetic components of these 1998 triple-hybrid stains would later form six out of the eight viral gene segments in the 2009 flu outbreak.[44][45][46][47][48]
2007 Philippine outbreak in swine
Please help improve this article by expanding it. Further information might be found on the talk page. (April 2009)
On August 20, 2007 Department of Agriculture officers investigated the outbreak (epizootic) of swine flu in Nueva Ecija and Central Luzon, Philippines. The mortality rate is less than 10% for swine flu, unless there are complications like hog cholera. On July 27, 2007, the Philippine National Meat Inspection Service (NMIS) raised a hog cholera "red alert" warning over Metro Manila and 5 regions of Luzon after the disease spread to backyard pig farms in Bulacan and Pampanga, even if these tested negative for the swine flu virus.[49][50]
2009 outbreak in humans
Main article: 2009 flu pandemic
The H1N1 viral strain implicated in the 2009 flu pandemic among humans often is called "swine flu" because initial testing showed many of the genes in the virus were similar to influenza viruses normally occurring in North American swine.[51] Further research has shown that three-quarters or six out of the eight gene segments of the 2009 virus arose from the 1998 North American swine flu strains which emerged from the first-ever reported triple-hybrid virus of 1998.[44][44][47][47][48]
In late April, Margaret Chan, the World Health Organization's director-general, declared a "public health emergency of international concern" under the rules of the WHO's new International Health Regulations when the first two cases of the H1N1 virus were reported in the United States, followed by hundreds of cases in Mexico.[52][53] Following the initial cases in the USA and Mexico, on May 2, 2009, it was reported in pigs at a farm in Alberta, Canada, with a link to the outbreak in Mexico. The pigs are suspected to have caught this new strain of virus from a farm worker who recently returned from Mexico, then showed symptoms of an influenza-like illness.[54] These are probable cases, pending confirmation by laboratory testing.
The new strain was initially described as an apparent reassortment of at least four strains of influenza A virus subtype H1N1, including one strain endemic in humans, one endemic in birds, and two endemic in swine.[51] Subsequent analysis suggested it was a reassortment of just two strains, both found in swine.[55] Although initial reports identified the new strain as swine influenza (i.e., a zoonosis originating in swine), its genetic origin was only later revealed to have been mostly a descendant of the triple-reassortment virus which emerged in factory farms in the United States in 1998.[44][44][47][47][48] Several countries took precautionary measures to reduce the chances for a global pandemic of the disease.[56] The 2009 swine flu has been compared to other similar types of influenza virus in terms of mortality: "in the US it appears that for every 1000 people who get infected, about 40 people need admission to hospital and about one person dies."[57] There are fears that swine flu will become a major global pandemic at the end of the year (coinciding with the Northern Hemisphere winter months), with many countries planning major vaccination campaigns.[58]
Transmission
Transmission between pigs
Influenza is quite common in pigs, with about half of breeding pigs having been exposed to the virus in the US.[59] Antibodies to the virus are also common in pigs in other countries.[59]
The main route of transmission is through direct contact between infected and uninfected animals.[11] These close contacts are particularly common during animal transport. Intensive farming may also increase the risk of transmission, as the pigs are raised in very close proximity to each other.[60][61] The direct transfer of the virus probably occurs either by pigs touching noses, or through dried mucus. Airborne transmission through the aerosols produced by pigs coughing or sneezing are also an important means of infection.[11] The virus usually spreads quickly through a herd, infecting all the pigs within just a few days.[2] Transmission may also occur through wild animals, such as wild boar, which can spread the disease between farms.[62]
Transmission to humans
People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur.[63] Vaccination of these workers against influenza and surveillance for new influenza strains among this population may therefore be an important public health measure.[64] Transmission of influenza from swine to humans who work with swine was documented in a small surveillance study performed in 2004 at the University of Iowa.[65] This study among others forms the basis of a recommendation that people whose jobs involve handling poultry and swine be the focus of increased public health surveillance.[63] Other professions at particular risk of infection are veterinarians and meat processing workers, although the risk of infection for both of these groups is lower than that of farm workers.[66]
Interaction with avian H5N1 in pigs
Pigs are unusual as they can be infected with influenza strains that usually infect three different species: pigs, birds and humans.[67] This makes pigs a host where influenza viruses might exchange genes, producing new and dangerous strains.[67] Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam, increasing fears of the emergence of new variant strains.[68] H3N2 evolved from H2N2 by antigenic shift.[69] In August 2004, researchers in China found H5N1 in pigs.[70]
Main symptoms of swine flu in swine.[2]These H5N1 infections may be quite common: in a survey of 10 apparently healthy pigs housed near poultry farms in West Java, where avian flu had broken out, five of the pig samples contained the H5N1 virus. The Indonesian government has since found similar results in the same region. Additional tests of 150 pigs outside the area were negative.[71][72]
Signs and symptoms
In swine
In pigs influenza infection produces fever, lethargy, sneezing, coughing, difficulty breathing and decreased appetite.[11] In some cases the infection can cause abortion. Although mortality is usually low (around 1–4%),[2] the virus can produce weight loss and poor growth, causing economic loss to farmers.[11] Infected pigs can lose up to 12 pounds of body weight over a 3 to 4 week period.[11]
In humans
Main symptoms of swine flu in humans[73]Direct transmission of a swine flu virus from pigs to humans is occasionally possible (called zoonotic swine flu). In all, 50 cases are known to have occurred since the first report in medical literature in 1958, which have resulted in a total of six deaths.[74] Of these six people, one was pregnant, one had leukemia, one had Hodgkin disease and two were known to be previously healthy.[74] Despite these apparently low numbers of infections, the true rate of infection may be higher, since most cases only cause a very mild disease, and will probably never be reported or diagnosed.[74]
In this video, Dr. Joe Bresee, with CDC's Influenza Division, describes the symptoms of swine flu and warning signs to look for that indicate the need for urgent medical attention.
See also: See this video with subtitles on YouTube [1]According to the Centers for Disease Control and Prevention (CDC), in humans the symptoms of the 2009 "swine flu" H1N1 virus are similar to those of influenza and of influenza-like illness in general. Symptoms include fever, cough, sore throat, body aches, headache, chills and fatigue. The 2009 outbreak has shown an increased percentage of patients reporting diarrhea and vomiting.[75] The 2009 H1N1 virus is not zoonotic swine flu, as it is not transmitted from pigs to humans, but from person to person.
Because these symptoms are not specific to swine flu, a differential diagnosis of probable swine flu requires not only symptoms but also a high likelihood of swine flu due to the person's recent history. For example, during the 2009 swine flu outbreak in the United States, CDC advised physicians to "consider swine influenza infection in the differential diagnosis of patients with acute febrile respiratory illness who have either been in contact with persons with confirmed swine flu, or who were in one of the five U.S. states that have reported swine flu cases or in Mexico during the 7 days preceding their illness onset."[76] A diagnosis of confirmed swine flu requires laboratory testing of a respiratory sample (a simple nose and throat swab).[76]
The most common cause of death is respiratory failure. Other causes of death are pneumonia (leading to sepsis)[77], high fever (leading to neurological problems), dehydration (from excessive vomiting and diarrhea) and electrolyte imbalance. Fatalities are more likely in young children and the elderly.
Diagnosis
Thermal scanning of passengers arriving at Singapore Changi airport.The CDC recommends real time RT-PCR as the method of choice for diagnosing H1N1.[78] This method allows a specific diagnosis of novel influenza (H1N1) as opposed to seasonal influenza. Near-patient point of care tests are in development.[79]
Prevention
Prevention of swine influenza has three components: prevention in swine, prevention of transmission to humans, and prevention of its spread among humans.
In swine
Methods of preventing the spread of influenza among swine include facility management, herd management, and vaccination (ATCvet code: QI09AA03). Because much of the illness and death associated with swine flu involves secondary infection by other pathogens, control strategies that rely on vaccination may be insufficient.
Control of swine influenza by vaccination has become more difficult in recent decades, as the evolution of the virus has resulted in inconsistent responses to traditional vaccines. Standard commercial swine flu vaccines are effective in controlling the infection when the virus strains match enough to have significant cross-protection, and custom (autogenous) vaccines made from the specific viruses isolated are created and used in the more difficult cases.[80][81] Present vaccination strategies for SIV control and prevention in swine farms typically include the use of one of several bivalent SIV vaccines commercially available in the United States. Of the 97 recent H3N2 isolates examined, only 41 isolates had strong serologic cross-reactions with antiserum to three commercial SIV vaccines. Since the protective ability of influenza vaccines depends primarily on the closeness of the match between the vaccine virus and the epidemic virus, the presence of nonreactive H3N2 SIV variants suggests that current commercial vaccines might not effectively protect pigs from infection with a majority of H3N2 viruses.[82][83] The United States Department of Agriculture researchers say that while pig vaccination keeps pigs from getting sick, it does not block infection or shedding of the virus.[84]
Facility management includes using disinfectants and ambient temperature to control virus in the environment. The virus is unlikely to survive outside living cells for more than two weeks, except in cold (but above freezing) conditions, and it is readily inactivated by disinfectants.[2] Herd management includes not adding pigs carrying influenza to herds that have not been exposed to the virus. The virus survives in healthy carrier pigs for up to 3 months and can be recovered from them between outbreaks. Carrier pigs are usually responsible for the introduction of SIV into previously uninfected herds and countries, so new animals should be quarantined.[59] After an outbreak, as immunity in exposed pigs wanes, new outbreaks of the same strain can occur.[2]
In humans
Prevention of pig to human transmission
Swine can be infected by both avian and human influenza strains of influenza, and therefore are hosts where the antigenic shifts can occur that create new influenza strains.
The transmission from swine to human is believed to occur mainly in swine farms where farmers are in close contact with live pigs. Although strains of swine influenza are usually not able to infect humans this may occasionally happen, so farmers and veterinarians are encouraged to use a face mask when dealing with infected animals. The use of vaccines on swine to prevent their infection is a major method of limiting swine to human transmission. Risk factors that may contribute to swine-to-human transmission include smoking and not wearing gloves when working with sick animals.[85]
Prevention of human to human transmission
Influenza spreads between humans through coughing or sneezing and people touching something with the virus on it and then touching their own nose or mouth.[86] Swine flu cannot be spread by pork products, since the virus is not transmitted through food.[86] The swine flu in humans is most contagious during the first five days of the illness although some people, most commonly children, can remain contagious for up to ten days. Diagnosis can be made by sending a specimen, collected during the first five days for analysis.[87]
Thermal imaging camera & screen, photographed in an airport terminal in Greece. Thermal imaging can detect elevated body temperature, one of the signs of the virus N1H1 (Swine influenza).Recommendations to prevent spread of the virus among humans include using standard infection control against influenza. This includes frequent washing of hands with soap and water or with alcohol-based hand sanitizers, especially after being out in public.[88] Chance of transmission is also reduced by disinfecting household surfaces, which can be done effectively with a diluted chlorine bleach solution.[89]
Experts agree that hand-washing can help prevent viral infections, including ordinary influenza and the swine flu virus. Also avoiding touching eyes, nose and mouth with hands prevents flu.[90] Influenza can spread in coughs or sneezes, but an increasing body of evidence shows small droplets containing the virus can linger on tabletops, telephones and other surfaces and be transferred via the fingers to the mouth, nose or eyes. Alcohol-based gel or foam hand sanitizers work well to destroy viruses and bacteria. Anyone with flu-like symptoms such as a sudden fever, cough or muscle aches should stay away from work or public transportation and should contact a doctor for advice.[91]
Social distancing is another tactic. It means staying away from other people who might be infected and can include avoiding large gatherings, spreading out a little at work, or perhaps staying home and lying low if an infection is spreading in a community. Public health and other responsible authorities have action plans which may request or require social distancing actions depending on the severity of the outbreak.
Vaccination
Main article: 2009 flu pandemic vaccine
Vaccines are available for different kinds of swine flu. The U.S. Food and Drug Administration (FDA) approved the new swine flu vaccine for use in the United States on September 15, 2009.[92] Studies by the National Institutes of Health (NIH), show that a single dose creates enough antibodies to protect against the virus within about 10 days.[92]
Treatment
In swine
As swine influenza is rarely fatal to pigs, little treatment beyond rest and supportive care is required.[59] Instead veterinary efforts are focused on preventing the spread of the virus throughout the farm, or to other farms.[11] Vaccination and animal management techniques are most important in these efforts. Antibiotics are also used to treat this disease, which although they have no effect against the influenza virus, do help prevent bacterial pneumonia and other secondary infections in influenza-weakened herds.[59]
In humans
If a person becomes sick with swine flu, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms). Beside antivirals, supportive care at home or in hospital, focuses on controlling fevers, relieving pain and maintaining fluid balance, as well as identifying and treating any secondary infections or other medical problems. The U.S. Centers for Disease Control and Prevention recommends the use of Tamiflu (oseltamivir) or Relenza (zanamivir) for the treatment and/or prevention of infection with swine influenza viruses; however, the majority of people infected with the virus make a full recovery without requiring medical attention or antiviral drugs.[93] The virus isolates in the 2009 outbreak have been found resistant to amantadine and rimantadine.[94]
In the U.S., on April 27, 2009, the FDA issued Emergency Use Authorizations to make available Relenza and Tamiflu antiviral drugs to treat the swine influenza virus in cases for which they are currently unapproved. The agency issued these EUAs to allow treatment of patients younger than the current approval allows and to allow the widespread distribution of the drugs, including by non-licensed volunteers.[95]
See also
Wikimedia Commons has media related to: Swine flu
Wikinews has related news: Swine flu
2009 flu pandemic vaccine
Bird flu
Dog flu
Horse flu
Pandemic
Infectious disease
List of epidemics
സ്വാന് flow
Environmental flow study on Swan and Canning RiversProject Info Services
Email a friend this article Print This Article This project involved providing the basis to determine environmental flow objectives and associated river flow regimes for the waterways of the Swan Canning River system for the chapter entitled ‘Environmental Flows’ in the Water Quality Improvement Plan (WQIP).
GHD was commissioned by the Swan River Trust of Western Australia to analyse flow data from 12 representative stations throughout the WQIP area. In particular this involved the analysis of:
Surface and groundwater influence on the flow regime of main drains and main tributaries
Groundwater influence on surface flow regime
Seasonality of the surface flows
In addition, the knowledge gaps encountered during the project were identified and prioritised for future works.
Water Sciences
Water managers must balance the economic, social and environmental demands associated with our wetlands, rivers, coastal and ocean environments.
GHD’s Water Sciences services combine our technical aquatic and marine capacity with our water engineering services to provide innovative, cost-effective water resource management solutions for our clients.
Read More
Email a friend this article Print This Article This project involved providing the basis to determine environmental flow objectives and associated river flow regimes for the waterways of the Swan Canning River system for the chapter entitled ‘Environmental Flows’ in the Water Quality Improvement Plan (WQIP).
GHD was commissioned by the Swan River Trust of Western Australia to analyse flow data from 12 representative stations throughout the WQIP area. In particular this involved the analysis of:
Surface and groundwater influence on the flow regime of main drains and main tributaries
Groundwater influence on surface flow regime
Seasonality of the surface flows
In addition, the knowledge gaps encountered during the project were identified and prioritised for future works.
Water Sciences
Water managers must balance the economic, social and environmental demands associated with our wetlands, rivers, coastal and ocean environments.
GHD’s Water Sciences services combine our technical aquatic and marine capacity with our water engineering services to provide innovative, cost-effective water resource management solutions for our clients.
Read More
സ്വാന് flo
Environmental flow study on Swan and Canning RiversProject Info Services
Email a friend this article Print This Article This project involved providing the basis to determine environmental flow objectives and associated river flow regimes for the waterways of the Swan Canning River system for the chapter entitled ‘Environmental Flows’ in the Water Quality Improvement Plan (WQIP).
GHD was commissioned by the Swan River Trust of Western Australia to analyse flow data from 12 representative stations throughout the WQIP area. In particular this involved the analysis of:
Surface and groundwater influence on the flow regime of main drains and main tributaries
Groundwater influence on surface flow regime
Seasonality of the surface flows
In addition, the knowledge gaps encountered during the project were identified and prioritised for future works.
Water Sciences
Water managers must balance the economic, social and environmental demands associated with our wetlands, rivers, coastal and ocean environments.
GHD’s Water Sciences services combine our technical aquatic and marine capacity with our water engineering services to provide innovative, cost-effective water resource management solutions for our clients.
Read More
Email a friend this article Print This Article This project involved providing the basis to determine environmental flow objectives and associated river flow regimes for the waterways of the Swan Canning River system for the chapter entitled ‘Environmental Flows’ in the Water Quality Improvement Plan (WQIP).
GHD was commissioned by the Swan River Trust of Western Australia to analyse flow data from 12 representative stations throughout the WQIP area. In particular this involved the analysis of:
Surface and groundwater influence on the flow regime of main drains and main tributaries
Groundwater influence on surface flow regime
Seasonality of the surface flows
In addition, the knowledge gaps encountered during the project were identified and prioritised for future works.
Water Sciences
Water managers must balance the economic, social and environmental demands associated with our wetlands, rivers, coastal and ocean environments.
GHD’s Water Sciences services combine our technical aquatic and marine capacity with our water engineering services to provide innovative, cost-effective water resource management solutions for our clients.
Read More
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