Influenza is a contagious disease of the respiratory system, affecting the upper airways and the lungs. There are three types of influenzas: The A types infect birds and some mammals, are very contagious, and are the only types to have caused human pandemics. (There have been three pandemics in the last century: 1918, 1957, and 1968).  B types infect only humans and cause the familiar annual flu outbreaks. C types affect only humans and symptoms are very mild. 

Every influenza virus is made up of two proteins—hemagglutinin and neuraminidase.  There are 16 types of hemagglutinin (H) and nine types of neuraminidase (N), which means there are 144 possible combinations of A-type influenzas.  The current subtype that we are watching is called H5N1. There are, of course, many unanswered questions about the virus.  Useful links with updated information are listed below.      Top of page

When and where did it start?

The H5N1 virus has been spreading westward since its first appearance in Hong Kong in 1997. It has been circulating in Southeast Asia for the past decade but recently began spreading much more rapidly to Europe and the Middle East. It is therefore possible that the virus will reach the United States and North America.     Top of page

How does it travel?

Wild birds carry many diseases, among them A-type influenzas. Aquatic waterfowl are carriers of essentially all 144 combinations of the influenza A virus. However, they are asymptomatic carriers, which means they do not show any symptoms of having the disease.

Usually the virus carried by its bird hosts is a mild one, sickening neither the animal host nor other birds the host comes in contact with. Ordinarily poultry and related species come in contact with wild birds without any ill effects.  We do not yet know why the virus mutated from one of limited disease-causing ability in wild migratory birds and became something that devastates poultry.      Top of page

How do humans contract it?

Humans can contract avian influenzas through direct contact with infected poultry or objects contaminated by poultry feces or other secretions.  All reported cases of H5N1 bird flu in humans have been linked to close contact with infected poultry. While millions of poultry have died from H5N1, there have been only 191 confirmed human cases, which indicate that like most A types, this virus has a very difficult time jumping from birds to humans.

The virus has been mutating as it travels through bird flocks, and already there are several different strains of this flu circulating. In order for H5N1 to cause a human pandemic, the virus must eventually change into a form that causes easy human-to-human transmission. Avian influenza strains do not usually replicate well in humans, but they can mutate or undergo genetic “mixing” (also called “reassortment”) with other human strains. This kind of change will result in new strains with a marked increase in virulence for humans.      Top of page

What are the symptoms?

Symptoms of avian influenza in humans range from typical human influenza-like symptoms (fever, cough, sore throat, and muscle aches) to eye infections (such as conjunctivitis), pneumonia, and severe respiratory distress, as well as other life-threatening complications. The symptoms of avian influenza will depend on which virus caused the infection. In poultry, mild symptoms include decreased food consumption, lack of energy, respiratory signs (coughing and sneezing) and a decrease in egg production. Severe clinical signs include soft-shelled or misshapen eggs, swelling caused by excess fluid in the body, purplish skin discoloration, nasal discharge, respiratory distress, lack of coordination, diarrhea and sudden death.     Top of page

How serious is it?

The first human case of H5N1 was recorded in 2003.  As of 10 April 2006 there have been 191 confirmed cases and 109 deaths. We do not know how many people (particularly in rural areas) have contracted the flu, did not seek medical attention, and recovered. Therefore the mortality rate, which currently stands at 50%, may actually be much lower. The 1918 Spanish Influenza (H1N1), which was our most virulent pandemic and killed about 50 million people worldwide, had a mortality rate of 2.5%. Annually, 36,000 people in the United States die of flu (Influenza B) complications.

The concern right now among scientists and world leaders is that although there is a low probability of H5N1 mutating into something transmissible among humans, if it does happen, the consequences will be global and severe. Not only will there be short-term consequences (acute illness and death) but long-term economic shifts as populations decline and social infrastructure falls apart. Although some scientists say that we are overdue for another flu pandemic, it does not at all mean that the next one will involve H5N1. For example, an H7N7 subtype infected 83 people in the Netherlands in 2003, resulting in one death. At issue, then, is this: how well prepared do we need to be and what, in essence, do we need to be prepared for?      Top of page

Where do we stand?

Thus far the European Union (EU) has been doing an excellent job of surveillance and containment. Only two farms to date (in France and Germany) have been infected with avian flu—protective zones were established and there have been no other cases of infected farms. We are not yet certain how bird flu will arrive in North America. It could be carried by migratory birds, through the illegal import of birds, or by international travel from affected regions. The United States is currently focusing surveillance efforts on Alaska, which is an entry point for migratory birds.      Top of page

Preparation and Prevention

If the avian flu enters the USA, the following prevention measures will need to be observed. What each person must do is remain up-to-date on the latest information and take appropriate steps at each stage. There is no need to panic.  Practicing good hygiene is always essential (thoroughly washing hands in soap and water will remove any virus on your hands¹). Avoid eating undercooked poultry(a cooking temperature of 160 degrees is recommended by the World Health Organization²). There is a risk in buying imported products containing feathers or other bird parts from countries that have reported outbreaks of bird flu³. There is a risk in importing pet birds from such countries as well⁴ .

Right now, there is no vaccine.  Because the virus has not mutated into a form transmissible among humans, a vaccine cannot be created. Moreover, it is important to realize that it takes at least 4 months to create a vaccine and therefore one will not be available to everyone.  Lastly, this strain has and will continue to mutate. Birds in Southeast Asia are carrying a strain which differs from those strains found in some European flocks.  Therefore, several different vaccines will be needed to combat the various strains infecting people.       Top of page

How to deal with wild birds?

There is little point in culling wild flocks. First, as stated earlier, H5N1 may not turn out to be the cause of the next pandemic. Mass culling would disrupt the environment and no one knows what health consequences that might have—certainly they would be dramatic. Moreover, many birds have been tested for H5N1, and very few are found to carry it. The expense of culling would be prohibitive, and is not all guaranteed to solve anything, particularly if H5N1 remains primarily an animal disease.      Top of page

Avian flu and birders

Currently, avian flu is not a danger for people who watch or feed birds in North America. It’s safe to bird-watch. Moreover, it could help contain the disease. Birders hold a key role in preventing the flu from spreading. Birders could be the first ones to reports sighting of groups of dead birds and also the movement of key migrating species, allowing authorities to act fast and control avian flu.      Top of page

What to do if you find a suspect dead bird?

Birders might be the first ones to notice strange deaths among migratory birds, particularly waterfowls. To report a suspect bird, please call the USDA toll free hotline 1-866-536-7593.      Top of page

Recommendations for pets

In case the virus reaches the United States, pets might experience some restrictions. The United States government has not yet suggested that outdoor pets minimize contact with wild birds or poultry⁵.  However, because H5N1 has the ability to infect certain other mammals (such as cats, ferrets, dogs, and pigs) it would be wise to make sure your pets neither consume any birds nor come in close contact with them, particularly migratory waterfowl.  Bird feeders are also not currently considered a threat, though one should always practice good hygiene and disinfection while cleaning feeders, as many birds carry diseases that can infect humans⁶. If H5N1 is detected in the United States, efforts would focus on minimizing contact between wild birds and domestic flocks, increasing security measures on farms, and educating hunters and the public with greater attention to pandemic preparedness.

Links

Below are useful links where you will find detailed and recent information about the avian flu.

The Worldwide Health Organization (WHO)website contains all the latest information about the disease’s expansion as well as detailed health-related recommendations.

http://www.who.int/csr/disease/avian_influenza/en/index.html

The Center for Disease Control and Prevention is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans.

http://www.cdc.gov/flu/avian/index.htm

This is the official U.S. government Web site for information on pandemic flu and avian influenza.

http://www.pandemicflu.gov/

The National Wildlife Health Center provides information, technical assistance, research, education, and leadership on national and international wildlife issues.

http://www.nwhc.usgs.gov/disease_information/avian_influenza/index.jsp

This Cornell webpage explains why that Avian Flu is not a danger for bird watchers.

http://www.birds.cornell.edu/avian_flu_link.html

Dr. Scott Newman, a Conservation Medicine scientist from Wildlife Trust in New York, compiled a very detailed informational website.  As a member of the Wildlife Trust’s Bioscape Initiative, NYC Audubon is a partner organization.

http://www.wildlifetrust.org/enter.cgi?p=news/2006/0101_1_avian.htm

ProMED Mail is the global electronic reporting system for outbreaks of emerging infectious diseases and toxins, open to everyone. ProMED-mail is a program of the International Society for Infectious Diseases.http://www.promedmail.org

The Food and Agriculture Organization of the United Nations provides additional information on pets and avian influenza.  http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian_cats.html

This BBC webpage hold an interesting interactive map of the disease spread.

http://news.bbc.co.uk/1/shared/spl/hi/world/05/bird_flu_map/html/1.stm

These additional websites will also help you know more about avian flu.

American Bird Conservancy http://www.abcbirds.org/

National: Audubon http://www.audubon.org

Audubon New York http://ny.audubon.org/

In-text references:

¹ http://www.cdc.gov/flu/avian/gen-info/qa.htm (hand washing)

² http://www.who.int/features/qa/32/en/index.html (undercooked poultry)

³ http://www.pandemicflu.gov/general/faq.html (imported bird products)

⁴ http://www.pandemicflu.gov/general/faq.html (imported birds)

⁵ http://www.pandemicflu.gov/general/faq.html (bird feeders)

⁶ http://www.pandemicflu.gov/general/faq.html (pets indoors)

Document compiled by Nicole Delacretaz and Morgan Avery.      Top of page