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Putnam County Health Department |
          
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Avian Influenza
by: Mark Eckhart, MPH Epidemiologist
Avian (bird) influenza (flu) refers to a large group of different influenza viruses that primarily affect birds. Bird flu viruses occur naturally among birds in the wild. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them. Infected birds shed flu virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated excretions.
On
rare occasions, these bird viruses can infect other species, including pigs and
humans. The vast majority of avian
influenza viruses do not infect humans. However, it is believed that most
cases of bird flu infections in humans reported since 1997 have resulted from
close contact with infected poultry or contaminated surfaces.
Health
experts have been monitoring a new and extremely severe influenza virus – the
H5N1 strain – for almost eight years. The H5N1 strain first infected humans in
Hong Kong in 1997, causing 18 cases, including six deaths. Since mid-2003, this
virus has caused the largest and most severe outbreaks in poultry on record in
Asia and parts of Europe. In December 2003, infections in people exposed to sick
birds were identified.
For
this reason, avian influenza, H5N1, is a strain with pandemic potential. It
might ultimately adapt and mutate into a strain that is contagious among humans,
thus possessing the ability to spread from person to person. A pandemic occurs
when a new influenza virus emerges and starts spreading as easily as normal
influenza – by coughing and sneezing. Because the virus is new, the human
immune system will have no pre-existing immunity. This makes it likely that
people who contract pandemic influenza will experience more serious disease than
that caused by normal influenza. Once this adaptation occurs, it will no longer
be a bird virus--it will be a human influenza virus. An influenza pandemic is a
rare but recurrent event. Fortunately, the virus does not jump easily from birds
to humans or spread readily and sustainably among humans.
There currently is no commercially available vaccine to protect humans against the H5N1 virus that is being seen in Asia and Europe. However, vaccine development efforts are taking place. Research studies to test a vaccine to protect humans against H5N1 virus began in April 2005, and a series of clinical trials is underway. According to the Centers for Disease Control and Prevention (CDC), hand washing is the single most important action one can take to prevent the onset of illness (HandWashPoster.pdf).
Federal,
state and local public health have been working together to prepare for a
possible influenza pandemic. Because public health often deals with re-emerging
or new diseases such as SARS, many of these functions are already in place.
Local and state response will likely hinge on resources available at the federal
level. The CDC is doing a “full-court press” in preparing for an eventual
pandemic; a national strategy for pandemic influenza was released in November of
2005. The Putnam County Health Department wrote a pandemic influenza plan in
2004. Revisions to the Putnam County Plan are occurring based upon new
information as it is made available. For more specific information please visit the links below or contact your local health department or public health epidemiologist.
Centers for Disease Control and Prevention: Avian Influenza Page http://www.cdc.gov/flu/avian/index.htm World Health Organization: http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html United States Department of Agriculture: http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?navtype=MA&navid=HOME Ohio Department of Health Pandemic Flu Information: http://www.ohiopandemicflu.gov/ BioSecurity for the Birds: http://www.aphis.usda.gov/vs/birdbiosecurity/index.html Pandemic Flu:
U.S. Food & Drug Administration News Release on New Vaccine: http://www.fda.gov/bbs/topics/NEWS/2007/NEW01611.html
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