Avian Flu (Bird Flu) or H5N1
Public health officials in Asia and the Middle East are keeping a close eye on avian (bird) flu. The official name is H5N1 flu. In countries like Indonesia, Viet Nam, Pakistan and Egypt, a small number of people have caught this flu virus after coming into direct contact with an infected or dead bird. In a few cases, infected people have passed avian flu on to others.
The H5N1 strain of avian flu currently active in these countries is severe. Since 2003, about half of the people who have become sick from avian flu have died from it. Humans have almost no natural immunity to H5N1 infection.
If H5N1 viruses were to change enough to easily pass from human to human, the result could be an avian flu pandemic with high illness and death rates worldwide.
The virus is often spread in live bird markets, auctions, shows and swap meets, places where birds from different areas are brought together.
Human Infection with Avian Influenza Viruses
So far, the person to person spread of H5N1 avian flu has been very rare, limited and unsustained. But the virus poses an important public health threat because we lack immunity. Some common medicines don’t work for this type of flu, and there is no vaccine for avian flu.
One worrisome sign — research suggests that H5N1 viruses are becoming more capable of causing disease in other animals than in the past. One study found that ducks infected with H5N1 virus are now shedding more virus for longer periods without showing symptoms of illness, which could make it easier for ducks to transmit disease to other birds and possibly to humans as well.
Research has also documented H5N1 virus infection among pigs, cats, dogs, tigers, leopards, wild civet cats, and martens (a weasel-like mammal) in other parts of the world. The avian flu strains continue to adapt, and we expect that other mammals may become vulnerable to infection in the future.
Symptoms of Bird Flu in People
Symptoms of bird flu in humans have ranged from typical flu-like symptoms, such as fever, cough, sore throat and muscle aches, to eye infections, pneumonia and life-threatening lung diseases.
Treatment and Vaccination for H5N1 Virus in Humans
Two of the antiviral medicines commonly used for flu do not work for the H5N1 virus that has caused the death of people in Asia. Two other antiviral medications, oseltamivir and zanamivir, would probably work to treat influenza caused by H5N1 virus, but more study is needed.
In 2007, the Federal Drug Administration (FDA) announced the first approval in the United States of a vaccine for humans against the H5N1 influenza virus, commonly known as avian or bird flu.
The vaccine could be used in the event the current H5N1 avian virus were to develop the capability to efficiently spread from human to human, resulting in the rapid spread of the disease across the globe. Should such an H5N1 pandemic emerge, the vaccine may provide early limited protection in the months before a vaccine tailored to the pandemic strain of the virus could be developed and produced.
Avian Flu Could Harm Poultry Operations
The current strain of avian flu frequently kills domestically raised chickens, ducks and turkeys. Since South Carolina is a leading state in the nation for production of domestic poultry, a widespread infection among flocks could harm the state’s economy.
Avian flu viruses occur naturally in the intestines of wild birds and ducks, but those birds rarely get sick from them. Infected birds shed the virus in their saliva, nasal secretions, and feces.
Domesticated birds get the virus through direct contact with infected waterfowl or other infected birds or through contact with surfaces (such as dirt or cages), water and feed contaminated with the virus.
Avian flu in domestic poultry causes two main forms of disease.
- The low pathogenic form usually causes mild symptoms such as ruffled feathers and a drop in egg production. The symptoms often go undetected.
- The highly pathogenic form spreads rapidly through poultry flocks, causing disease that affects multiple internal organs. The death rate among domestically raised chickens, turkeys and ducks can reach 90 to 100 percent, often within 48 hours.
The Clemson University Livestock Poultry Health Division keeps constant watch for cases of avian flu in birds in South Carolina.
What’s Being Done to Protect You
If there is ever an outbreak of avian influenza in South Carolina, DHEC will tell you how to protect yourself.
- DHEC and the CDC keep constant watch for cases of avian influenza. Any possible cases are investigated to help prevent possible spread.
- The CDC and the World Health Organization monitor influenza activity around the world, including avian flu.
- The CDC has hired a company to develop and produce a vaccine to help prevent bird flu.
- DHEC has developed a comprehensive influenza emergency plan for the state of South Carolina.
- DHEC helps train physicians, clinicians and laboratory workers in the detection of possible human cases of H5N1.
- The Clemson University Livestock Poultry Health Division keeps constant watch for cases of avian flu in birds in South Carolina.
Updated Information for Travelers about Avian Influenza A(H5N1) is available at the CDC Travelers’ Health website.