Influenza A virus subtype H7N2

H7N2 is a subtype of the species Influenza A virus (sometimes called bird flu virus).

One person in Virginia, US in 2002 and one person in New York, US, in 2003 were found to have serologic evidence of infection from H7N2; both fully recovered.

In February 2004, an outbreak of low pathogenic avian influenza (LPAI) A (H7N2) was reported on 2 chicken farms in Delaware and in four live bird markets in New Jersey supplied by the same farms. In March 2004, surveillance samples from a flock of chickens in Maryland tested positive for LPAI H7N2. It is likely that this was the same strain. [ [http://www.cdc.gov/flu/avian/outbreaks/us.htm CDC] ]

A CDC study following the 2002 outbreaks of H7N2 in commercial poultry farms in western Virginia concluded::An important factor contributing to rapid early spread of AI virus infection among commercial poultry farms during this outbreak was disposal of dead birds via rendering off-farm. Because of the highly infectious nature of AI virus and the devastating economic impact of outbreaks, poultry farmers should consider carcass disposal techniques that do not require off-farm movement, such as burial, composting, or incineration. [ [http://avianinfluenza.researchtoday.net/cgi-bin/researchtoday.cgi?TopicName=Avian%20Influenza&AbstractID=19 flu research] ]

On 24 May 2007, an outbreak of H7N2 was confirmed at a poultry farm near Corwen, in Wales from tests on chickens that died from H7N2. The owners of the Conwy farm bought 15 Rhode Island Red chickens two weeks prior but all died from H7N2. The 32 other poultry at the site were slaughtered. A one kilometer exclusion zone was put in force around the property in which birds and bird products cannot be moved and bird gathering can only take place under licence. Nine people who were associated with the infected or dead poultry and reported flu-like symptoms were tested. Four tested positive for evidence of infection from H7N2 and were successfully treated for mild flu. [ [http://news.bbc.co.uk/1/hi/wales/6686995.stm BBC] [http://www.physorg.com/news99479831.html physorg] ] In early June it was discovered that the virus had spread to a poultry farm 70 miles (113 km) away near St. Helens in north-west England. All the poultry at the farm were slaughtered and a 1 km exclusion zone imposed. [ [http://news.scotsman.com/latest.cfm?id=897092007 Scotsman News] article "Mild bird flu virus spreads to north-west England" June 8, 2007]

A 2008 analysis of the New York 2003 case concluded that the H7N2 virus responsible could be evolving toward the same strong sugar-binding properties of the three worldwide viral pandemics in 1918, 1957 and 1968. (Human flus and bird flus differ in the molecules they are good at binding with because mammals and birds differ in the molecules on the cell surface to be bound with. Humans have very few cells with the bird sugar on its cell surface.) A study with ferrets showed that this H7N2 strain could be passed from mammal to mammal. [ [http://www.timesonline.co.uk/tol/news/uk/science/article4009755.ece timesonline] article "Scientists identify second H7 strain of bird flu that could cause pandemic" published May 27, 2008] [ [http://afp.google.com/article/ALeqM5h7wLpfDIOFFLxuDYYau8_IHOZnXA Evolution of flu strains points to higher risk of pandemic: study] ]

ources and notes

* [http://www.cdc.gov/flu/avian/gen-info/avian-flu-humans.htm CDC avian flu information]

Further reading

* [http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=140442 Research Update on H7n2 Avian Influenza Virus in Turkeys and Chickens]
* [http://www.google.com/search?q=cache:Gt5OP_JYLWYJ:www.umaine.edu/livestock/NECAD/2002%2520Abstracts/DHenzler.doc+H7N2&hl=en&gl=us&ct=clnk&cd=16 Epidemiology of an H7N2 Avian Influenza Outbreak in Broilers in Pennsylvania in November 2001- January 2002]
* [http://www.hpa.org.uk/hpr/archives/2007/news2007/news2207.htm#av_flu Avian influenza H7N2 in Wales and the Northwest of England]
* [http://www.wales.nhs.uk/sites3/news.cfm?orgid=719&contentid=6846 North Wales bird flu outbreak ends]