Asian H5N1 Avian Influenza in People

What is the public health significance of avian influenza?

•    Prior to 1997 there were only three known instances of avian influenza viruses being implicated in human infection. In 1959, 1979 and 1996 evidence of influenza virus was detected in humans and in each case an H7N7 was involved.

•    In 1997 in Hong Kong highly pathogenic H5N1 avian influenza was detected in 18 humans, 6 of whom died.  A serological survey of poultry workers revealed that approximately 10% had antibodies to H5.  Antibody to H5 was associated with more intensive poultry exposure, such as butchering and exposure to sick poultry.

•    In 1999 mildly pathogenic H9N2 influenza viruses were isolated from 7 people in Hong Kong and mainland China. None died.  Serological evidence of H9N2 was found in 19% of participants in a seroepidemiological survey.

• Evidence of anti-H7 antibodies was reported in 3.8% of serum samples collected from poultry workers in Italy during the period in 2003 when LPAI H7N3 virus was circulating.

•    In 2003 workers in Netherlands involved in killing chickens infected with highly pathogenic influenza became infected with H7N7 and one died.  H7N7 was found in 26 % of poultry workers involved in the outbreak who experienced conjunctivitis.

•    In 2003 one person in New York became ill and the illness was confirmed by CDC to be due to H7N2 in April of 2004.

•    In 2004 a highly pathogenic H7N3 caused mild infection in humans in British Columbia.

•    Scientists in the U.S. have recently found serological evidence (antibodies) of various subtypes of avian influenza in humans who have had contact with infected birds such as poultry workers (H7N2, Virginia, 2003) and waterfowl hunters (H11N9, Iowa, 2006).

•    Now highly pathogenic Asian H5N1 is circulating in poultry in several countries in Europe, Asia and Africa and humans are being infected after coming in contact with infected poultry.

What’s an influenza pandemic? Will highly pathogenic Asian H5N1 cause a pandemic?

•    A pandemic is a widespread infection – usually world wide.

•    A human influenza pandemic is a world wide infection in people with an influenza virus.  What is required for a human influenza pandemic is a susceptible (sero-negative) human population, an influenza virus that causes human illness and one that spreads efficiently from human to human.  The human population is sero-negatve to H5 viruses and this Asian H5N1 causes human illness; however it is not spreading efficiently from human to human.

•    It is difficult to predict whether or when highly pathogenic H5N1 bad bird flu will cause a pandemic.

What if somebody does find an infected bird – in North America, the U.S., in the Upper Midwest, or here in Minnesota? Does that mean we’re having a pandemic?

•    No – the H5N1 bird flu strain is still almost entirely a disease of birds. Right now, this is still a “bird pandemic” – not a human pandemic.

•    In rare cases, the H5N1 virus has caused human illness – but only in people who have had extensive, close contact with infected domestic poultry or their droppings.

•    There have been a limited number of human cases where human-to-human transmission was suspected, and in Indonesia recently scientists reported that human-to-human transmission had occurred.

•    Unless the H5N1 bird flu virus changes dramatically – so it can be passed easily from person to person – we are unlikely to see widespread human disease.

Does that mean we don’t need to be concerned about a flu pandemic?

•    Public health officials remain concerned about the possibility of a future pandemic. We need to be prepared for that possibility.

•    Three worldwide pandemics have occurred in the last century – and scientists believe that another pandemic will occur some day.

•    It the H5N1 bird flu strain changes, so it can be passed easily from person to person, it could still end up causing a pandemic. That may or may not happen. 

•    A pandemic could be also be caused by a completely different flu virus – one that we haven’t seen yet.

•    Public health officials at all levels of government are watching closely for changes in the H5N1 bird flu virus – and any other potential pandemic threats.

How have people been infected?  Center for Disease Control Q& A

•    The human infections with highly pathogenic H5N1 avian influenza, as well as all the other recorded instances of human infection with avian influenza, have resulted from intimate contact with infected animals or droppings.

•    Human infections with highly pathogenic Asian H5N1 have been associated with the backyard or village poultry systems, home slaughter and subsequent handling of diseased or dead birds.  Consuming raw duck blood soup, and mouth to mouth resuscitation of fighting cocks have been linked anecdotally to human infections.

•    Human infections have not been associated with commercial poultry.

•    Contact with infected wild birds (defeathering and butchering sick or dead swans) has been reported to be a source of infection in people (Azerbaijan, 2006).

•    Human infection with highly pathogenic avian influenza had not been associated with North or South American influenza viruses until the recent H7N3 outbreak in British Columbia.  Antibodies to mildly pathogenic H7N2 have been found in two people in the U.S.

How would I know if I had caught Asian H5N1?

•    Only a doctor can determine whether you have Asian H5N1.  Right now you can only get Asian H5N1 by contact with sick chickens, poultry products or other birds from those countries where infection is occurring. People that have been infected were in direct contact with sick birds or their droppings.

Are poultry workers in the United States at risk?

•    There has been no highly pathogenic Asian H5N1 influenza found in the United States.

•    Poultry flocks in Minnesota are routinely monitored for influenza.  Low pathogenic strains are occasionally detected. Highly pathogenic avian influenza has never been found in Minnesota.

•    If U.S. poultry flocks were to get infected with avian influenza, it would most likely be a U.S. strain of virus, not an East Asia strain.

•    U.S. poultry workers are not at high risk for exposure to the highly pathogenic H5N1 bad bird flu virus.

•    U.S. poultry workers should avoid live bird markets, smuggled birds of any kind, backyard poultry and cock fights.

Should people be concerned about swimming in lakes where waterfowl are present?

•    In East Asia, according to WHO “Swimming in water bodies where carcasses of dead infected birds have been discarded or which may have been contaminated by feces from infected ducks or other birds might be another source of exposure.”

•    The risk of being infected by swimming in the same water with infected waterfowl is unknown.

•    The amount of H5N1 virus required to infect a person and the route of infection (conjunctival, oral, nasal) is also unknown.

•    It is known that high concentrations of avian influenza viruses are excreted in waterfowl droppings. Waterfowl may excrete up to ten billion influenza viruses per day and this virus can remain infectious for weeks in water.

•    If Asian H5N1.avian influenza were detected in the U.S, precautions might be advised.

Should I be concerned about contact with wild birds or their droppings? What should I do to protect myself?

•    In general, people should try to avoid contact with wild birds or their droppings – not necessarily because of bird flu, but as a general health precaution.

•    If you can’t avoid contact with wild birds or their droppings, wash your hands, and avoid bringing feces into your home on shoes or clothing.

•    Clean your shoes or clothing as necessary.  A bleach solution and exposure to sunlight may be helpful for disinfecting shoes.

Is it safe to keep “back yard chickens” or other poultry, in or near my place of residence?

•    If you own birds, a few simple precautions can help you reduce any potential risk to your birds – or to your own health.

•    Monitor your birds daily for any signs of disease. In birds, flu causes swelling around the head and discharge from the eyes, nose and mouth.  The H5N1 strain causes severe illness and death in chickens and turkeys. 

•    Keep wild birds – especially waterfowl – away from your domestic birds.  Avoid exposing your birds to feed, water or bedding that may have been contaminated by wild birds. 

•    Avoid exposing your birds to sick birds. If your birds become severely ill – or die – consult a veterinarian promptly. 

•    Wash your hands thoroughly after working with your birds to minimize your any potential exposure to bird flu.

•    If you have questions about safe handling of your birds, contact the U.S Department of Agriculture at http://www.aphis.usda.gov/vs/birdbiosecurity or 1–866–536–7593.

If avian influenza arrives in the U.S., how are poultry workers, processing workers, natural resources workers, animal control agents and others protected from highly pathogenic Asian H5N1?

•    If highly pathogenic avian influenza strikes the U.S. CDC has guidelines for worker protection. Center for Disease Control

•    Separation is the watchword in reducing risk of Asian H5N1 avian influenza.  Avoiding waterfowl and their habitat, avoiding sick birds and washing hands are important measures to reduce risk.

What is the effect of this particular highly pathogenic Asian H5N1 in humans?

•    The Asian highly pathogenic H5N1 virus has infected over 200 people resulting in fever, respiratory symptoms and reduced circulating lymphocytes. About 50% of infected people have died.

•    Updates from WHO

Where is it now? What’s going on in Asia, Europe and Africa now?  Are there travel restrictions?

•    Asian H5N1 spread from China to Laos, Cambodia, Thailand, Indonesia, Malaysia, and subsequently also to central Asian countries, Europe and Africa.

•    Currently there are no travel restrictions.  If travel restrictions were put in place it might be difficult to travel to or from affected areas. World Health Organization and Center for Disease Control

•    www.pandemicflu.gov 

If I travel to these countries what precautions do I need to take?

•    Do not go to chicken farms or live bird markets.

•    Do not touch sick or dead chickens or other birds.

•    Do not touch live apparently healthy birds or waterfowl.

•    Do not slaughter, de-feather or butcher chickens.

•    Wash your hands with soap and water or sanitizer: before you eat, before you prepare meals, and after touching raw meat.

•    Eat only fully cooked meat and eggs (165 F).

•    On returning to the U.S. wash all your clothes and sanitize your shoes, do not visit a farm for three weeks, and if you become ill go to a clinic and tell your doctor where you have been.

What can I tell relatives who live in countries with Asian highly pathogenic H5N1 avian influenza?

•    If they own poultry they should control the entry of people or new poultry into the poultry yard, and keep the poultry in a protected environment. For more information, read this brochure.

•    This website has information on protecting poultry

•    Use precautions outlined in this document

•    Keep informed

What about eating chicken and other poultry meat? What about eating eggs - are there any concerns about the types we should be eating and the way they are cooked? For example, is eating hard boiled or scrambled eggs safer than eating a fried egg, over easy if we were to have an outbreak?

•    Human infection has been associated with close contact with manure or respiratory secretions or blood from infected poultry. 

•    Human infection has not been associated with eating poultry meat or eggs.

•    If highly pathogenic H5N1 avian influenza were found in the U.S. the flocks (and eggs) would be destroyed.

•    If chickens were infected with highly pathogenic H5N1 and their meat or eggs made it to market there is a chance that the virus could be present; however, ordinary cooking temperatures (165 F) kill the virus.

•    It is likely that if Asian H5N1 came to the U.S. there would be recommendations from public health agencies to fully cook poultry meat and eggs (hard), but even if the disease came here the likelihood of infected meat or eggs reaching the table is remote.

•    WHO FAQs and www.avianinfluenzainfo.com

Can I get sick from eating chicken in the U.S?

•    There is no risk of getting Asian H5N1 from eating chicken in the U.S. because first of all there is no bad bird flu (highly pathogenic H5N1) in the U.S. There are several barricades in place to reduce the risk of infection to poultry and consequently reduce the risk to people.

•    Even if this virus entered the U.S., it is unlikely that it would enter the commercial poultry industry.

•    Even if it entered the commercial poultry industry, it would likely be detected and eradicated.

•    Even if it were not detected and immediately eradicated, every bird presented for slaughter in a USDA inspected plant is individually inspected for wholesomeness under the direction of a veterinarian.  Birds found to be sick are condemned and destroyed.

•    Even if an infected bird escaped detection and condemnation at slaughter, cooking destroys the virus.

•    In countries where Asian H5N1 has infected people, these infections have not been associated with commercial poultry production or with meat or eggs from commercial production, but rather human infection has been associated with close association with infected birds- home slaughter, for example.

Should consumers be concerned about buying and eating chickens or turkeys? What can they do to protect themselves?

•    Commercial poultry is monitored carefully for illness – including different strains of bird flu – by state and federal authorities.

•    In Minnesota, chickens and turkeys are monitored for disease by the state Department of Agriculture and the Board of Animal Health.

•    Even if the H5N1 bird flu virus is present in poultry, it is extremely unlikely that you would ever be infected by handling, cooking or consuming it.

•    Normal precautions for handling and cooking poultry should make it safe to prepare and eat. These precautions include

o    Cleaning all utensils and food preparation services thoroughly after working with raw poultry.

o    Washing your hands thoroughly after handling raw poultry.

o    Cooking poultry thoroughly – to an internal temperature of 165 degrees or higher – before eating it.

•    You should be following these precautions anyway, to prevent routine food-related diseases like salmonella.

What about eating eggs? Is there any special way eggs should be prepared?

•    There are no known cases where people have gotten H5N1 bird flu from eating eggs.

•    Cooking should kill any bacteria or viruses that may be present in eggs.

•    Eggs should be cooked thoroughly – so the yolks are not runny or liquid.

Where do the chickens come from that are sold in stores in the U.S.

•    The chickens that you buy in the U.S. are produced here in the U.S. or Canada.

•    Chickens purchased from a grocery store have been raised in the U.S. and slaughtered and inspected before they are sold.  Birds found to be sick are condemned.

•    If you purchase your chickens or other poultry from a live bird market or a farmer those birds have not been inspected.  You are your own inspector.

Are live bird markets in Minnesota inspected?

•    The facilities (but not the birds) are inspected four times a year for cleanliness.