Avian Influenza

Are humans at risk and if so how?  

There is no reason  to worry about public health. Avian Influenza is a disease of birds and whilst it can pass, with difficulty, to humans this requires very close contact with infected and diseased birds. This sort of bird flu  – the H7 avian flu remains largely a disease in birds, which does not transmit easily to humans.   Over the last decade only a small number of H7 avian flu infections have been confirmed in humans. In almost all of these cases the virus, in both low and high pathogenic forms, has only caused a mild disease, such as conjunctivitis (eye infection). Therefore at this stage this is a virus which only has extremely limited implications for human health.

Can animals other than birds be infected?  

Yes but it is rare. A few animals that will eat birds have become infected including cats that have been out hunting. There is no legal requirement to keep cats and dogs indoors but careful owners might wish to take the precaution of keeping dogs on leads and cats indoors in the protection zone.  

Is it safe to eat poultry or game?  

Yes. The Food Standards Agency has advised that eating properly cooked poultry products is not considered to be a risk. It also advises that the risk of infection through handling poultry meat is very low. Any risk can be minimised by hygienic handling of raw poultry meat. There are no substantiated reports of people becoming infected through these routes.  

Is it OK to touch uncooked poultry meat?

You should always wash your hands after handling raw poultry meat and eggs to avoid contamination from any bugs – so wash your hands very thoroughly.

Would cooking poultry and eggs properly kill the virus?

Cooking food thoroughly will kill bacteria and viruses. Poultry and eggs should always be cooked properly to avoid food poisoning anyway. You should follow the usual handling and cooking instructions for cooking poultry and it should be prepared hygienically and thoroughly cooked to an internal temperature of 70 degrees Celsius. If you're cooking a whole chicken or other bird, pierce the thickest part of the leg (between drumstick and thigh) with a clean knife or skewer until the juices run clear. The juices shouldn't have any pink or red in them and there should be no pink meat. You should not eat raw eggs or use raw eggs in dishes that will not be cooked. Eggs should be cooked until the whites are solid.      

Avian influenza in birds

Avian influenza (sometimes referred to as Bird Flu) naturally circulates in wild waterfowl such as ducks and geese often causing little or no symptoms. Many other bird species are susceptible to infection with these influenza viruses and in many of these species it may cause severe disease associated with high mortality.

Outbreaks associated with high bird mortality are called Highly Pathogenic Avian Influenza (HPAI) to distinguish them from less pathogenic influenza. Avian influenza viruses like other influenza viruses are described according to properties of two surface proteins: haemagglutinin (H) and neuraminidase (N).

Large outbreaks in poultry have, for example, been described in Pennsylvania in 1982 (H5N2), Mexico in 1993 (H5N2), Hong Kong in 1997 (H5N1) and The Netherlands in 2003 (H7N7).

In January 2004 avian influenza in poultry was confirmed in Vietnam. Subsequently, there have been very substantial outbreaks of avian influenza associated with high mortality affecting poultry in various countries of southeast and east Asia including Vietnam, Thailand, China, South Korea, Indonesia, Laos and Japan. These outbreaks are caused by H5N1 subtype of influenza A virus, the same subtype (but not identical to the virus) that caused the outbreak in Hong Kong in 1997.

Human cases

Very infrequently, avian influenza viruses are transmissible to humans. In the outbreak in Hong Kong in 1997 there were 18 confirmed human cases with 6 deaths. After thorough investigation all these cases all were linked to exposure to live infected poultry. In the Netherlands in 2003 there were 83 confirmed mild human cases and 1 death. Again there were no reported cases of person-to-person transmission.

In the current outbreak of avian influenza in southeast and east Asia human cases and deaths due to H5N1 have been reported from Vietnam and Thailand. The World Health Organisation provides regular updates on confirmed case numbers. Given the scale of the outbreaks in poultry the virus does not appear to infect humans easily. All human cases are investigated to determine the likely source of the infection. Influenza Pandemics

Outbreaks of influenza affecting many thousands and sometimes millions of people with high mortality occurred in 1918 ('Spanish'), 1957 (Asian), 1968 (Hong Kong) and 1977 (Russian). New subtypes of influenza caused these pandemics. These were probably formed by combination of genes from both avian and human influenza viruses.

Emergence of new highly pathogenic avian influenza with the capacity to infect humans is a concern because it may lead to circumstances where a new subtype of influenza can develop that both causes serious disease and can spread from person to person.

Travel and travellers returning

Up to date travel advice may be obtained from the Department of Health or the National Travel Health Network and Centre (NaTHNaC). The currently available influenza vaccine for the UK probably provides little or no protection against H5N1 influenza.

An up-to-date list of countries affected by outbreaks of H5N1 influenza in poultry can be found on the World Organisation for Animal Health website. The possibility of H5N1 influenza in travellers returning from countries currently experiencing outbreaks of avian influenza is low.

Guidelines for reporting and investigation of possible cases are available on the Health Protection Agency website.

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Source: Health Protection Agency