Avian Influenza (Bird Flu) (cont.)

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What are the complications of bird flu?

The complications of bird flu are frequently dire and include breathing problems, lung collapse, kidney failure, acute respiratory distress syndrome (ARDS), pneumonia, and death. The mortality rate (death rate) is about 60%. Fortunately, to date, there are only a relatively low number of infections worldwide (about 622 as of March 2013), but this number may increase with the new H7N9 strain.

What is the prognosis of bird flu?

The prognosis in human cases of bird flu remains poor. Many cases occur in people who are poor, live in rural areas in underdeveloped countries, and do not have access to modern intensive-care units or antiviral therapy. Approximately 60% of people diagnosed with bird flu eventually die from the disease; unfortunately, the H7N9 strain may have a similar death rate.

Can bird flu be prevented with a vaccine?

Although the U.S. government has a stockpile of vaccine against H5N1 bird flu, there is no commercially available vaccine for humans against any bird flu strains. However, bird flu can be prevented by avoiding contact with sick poultry originating in countries known to be affected by the virus. In 2011, Egypt had the most reported cases to date. Prevention also includes poultry-safety measures such as destroying flocks when sick birds are identified and vaccinating healthy flocks. Combined with import bans, this culling has effectively limited the spread of bird flu in outbreak situations but naturally has negative effects on the poultry and egg industry. Unlike SARS, which some investigators suggest has been eliminated from the world, or Ebola, which has a narrow geographic range, the bird flu continues to exist in significant areas of the world and can be spread widely by migrating birds. The poultry industry needs to follow FDA guidelines to protect their industry and workers from bird flu.

Properly handling and cooking of poultry and eggs can kill viruses like the bird flu virus. Hands should be washed before and after handling poultry and eggs, and surfaces that have come in contact with the food should be cleaned thoroughly with hot soapy water. Cooked poultry should have an internal temperature of at least 165 F.

Masks and other respiratory protection should be used when caring for patients with bird flu. If a person has close contact with an infected patient, the exposed person may be offered oseltamivir in an attempt to prevent infection.

In 2007, the FDA licensed the first vaccine in the United States for humans against the highly pathogenic bird flu virus. The vaccine is made from inactivated viruses and does not contain any live viruses. It has been shown to stimulate the immune system to make antibodies against the bird flu virus that could presumably protect a person from the bird flu. The vaccine has been purchased by the federal government for inclusion within the CDC's Strategic National Stockpile. It is not available to the general public in part because the United States does not currently have a problem with the highly pathogenic strain of bird flu. Vaccine side effects include a sore arm, fatigue, or temporary muscle aches. The vaccine has not been tested in large numbers of patients, however, and there may be other side effects that have not yet been detected. The current vaccine is effective against the strain that has caused the large outbreaks of bird flu, but it may not be as effective against a newly mutated strain found in 2011. Consequently, this vaccine seems unlikely to offer protection against the new H7N9 bird flu, but data is not available to date.

Research on vaccines against influenza viruses is ongoing, and new developments such as a vaccine that is directed against the common and relatively unchanging antigens on the influenza viruses may lead to a vaccine that is protective against most if not all influenza viruses. If such research is successful, potential influenza outbreaks, including avian flu, may be reduced or prevented in the future. Just before the outbreak of H7N9 flu, an article published in 2013 presented data on an experimental vaccine that was effective against flu viruses that possessed the N9 antigen, but it has only been tried in animal models.

Where can people find more information about bird flu?

The World Health Organization (http://www.who.int/csr/disease/avian_influenza/en/) provides current information about outbreaks and management of bird flu.

REFERENCES:

Pena, Sutton, et al. "Influenza viruses with rearranged genomes as live-attenuated vaccines." J. Virol. Online ahead of print, Feb. 28, 2013, doi:10.1128/JVI.02490-12

Switzerland. World Health Organization. "Cumulative Number of Confirmed Human Cases of Avian Influenza A(H5N1) Reported to WHO." Mar. 12, 2013. <http://www.who.int/influenza/human_animal_interface/H5N1_cumulative_table_archives/en/index.html>.

United States. Centers for Disease Control and Prevention. "Avian Influenza A (H7N9) Virus." Apr. 5, 2013. <http://www.cdc.gov/flu/avianflu/h7n9-virus.htm>.

United States. Flu.gov. <http://www.flu.gov>.

Van Kerkhove, M.D., E. Mumford, A.W. Mounts, J. Bresee, S. Ly, C.B. Bridges, and J. Otte. "Highly Pathogenic Avian Influenza (H5N1): Pathways of Exposure at the Animal-Human Interface, a Systematic Review." PLoS One 6.1 Jan. 24, 2011: e14582.


Medically Reviewed by a Doctor on 4/5/2013

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