Avian Flu (H5N1 Influenza)

The avian (bird) flu is a disease caused by the influenza type A virus that can affect birds, pigs and humans. Infection in humans is rare and usually occurs due to exposure to sick birds. However, when the avian bird flu does infect humans, it is fatal in more than half of cases, according to the Centers for Disease Control and Prevention.

H5N1 is a virus of particular concern to medical researchers because of these high fatality rates. While it’s extremely rare for the avian bird flu to pass from person to person, researchers around the world are working to develop vaccines to prevent people from getting the avian flu, in the event that a highly contagious strain of the disease develops, causing a avian flu pandemic.

Types of Avian Flu Virus

When the avian flu virus impacts a flock of birds, it can spread in one of two ways. The virus may be of "low pathogenic" status, which is rarely noticed by researchers. If the avian flu reaches a "highly pathogenic" status, however, it can spread rapidly through a flock of birds within hours and be fatal in every case.

Farmed poultry that has been affected by the avian flu will show signs of a viral attack. When a low pathogenic virus occurs:

• Birds may have less energy
• Birds may not lay many eggs
• Feathers may fall off or droop.

In contrast, when a highly pathogenic viral attack occurs, farmed birds usually die within two days. Humans can be at risk for contracting the avian flu due to certain factors — such as exposure to sick birds, and in rare cases, infected humans. Eating poultry cannot cause the avian flu.

How Is the Avian Flu Transmitted?

Anyone handling a sick bird can become infected with the avian flu virus. In rare cases, those who come in contact with an infected person can also become sick.

Additionally, the avian bird flu can be transferred from bird to human if:

• A human touches a surface where a sick bird has been
• Diseased poultry is not handled correctly
• Farmed birds come in contact with sick birds.

While many people believe that consuming poultry can cause an avian flu pandemic, this is simply not true. To date, there have been no cases of humans contracting the avian flu through cooked poultry consumption, since avian flu is not a food-borne illness.

When to Seek Medical Help

Avian flu is very rare, and its symptoms mimic those of the flu in humans. Avian flu symptoms usually begin about three days after infection, and may include:

• Conjunctivitis
• Cough and sore throat
• Fatigue
• Fever
• Muscle aches
• Nausea, vomiting and/or diarrhea.

In most cases, these symptoms are simply the cause of the flu or a cold. However, you’ll want to see your doctor right away if symptoms occur and you have recently:

• Been in contact with sick birds
• Spent time in a place where bird flu has infected humans (Asia, Africa and parts of Europe)
• Spent time on a farm outside the United States.

Resources

BBC News Staff. (2008). Health Q and A: Bird flu. Retrieved April 7, 2010, from the BBC News Web site: http://news.bbc.co.uk/2/hi/health/3422839.stm.

CBC News Staff. (2008). The next pandemic? Retrieved April 7, 2010, from the CBC Web site: http://www.cbc.ca/news/background/avianflu/.

Centers for Disease Control and Prevention Staff. (n.d). Information about Asian influenza (bird flu) and Asian influenza A (H5N1) virus. Retrieved April 9, 2010, from the Florida Department of Health Web site: http://www.doh.state.fl.us/chd/volusia/Documents/DisasterPreparedness/AvianFluKEYFACTS.pdf.

Mayo Clinic Staff. (2010). Bird flu (avian influenza). Retrieved April 7, 2010, from the Mayo Clinic Web site: http://www.mayoclinic.com/health/bird-flu/DS00566/DSECTION=symptoms.

World Health Organization Staff. (2005). Avian influenza frequently asked questions. Retrieved April 7, 2010, from the World Health Organization Web site: http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/#whatis.