Author(s): Amy Knopf, RN, MPH

Reviewer(s): Tao Sheng Kwan-Gett, MD, MPH, Medical Epidemiologist, Public Health - Seattle & King County Communicable Disease Epidemiology and Immunization Section

Date Authored: March 1, 2009

Avian Influenza and how it is Transmitted

Avian influenza (AI) is a group of influenza A viruses that usually infect birds. AI strains can be further classified as low pathogenic (LPAI) or highly pathogenic (HPAI) based on molecular and genetic characteristics and their ability to cause disease in birds. Avian influenza is transmitted from bird to bird either directly via infected feces or respiratory secretions or indirectly via contaminated cages, crates or other items. Avian influenza A subtypes H5 and H7 have been associated with HPAI, and are capable of mutating from low to high pathogenicity. Because of this risk, it is extremely important to immediately control any influenza A H5 or H7 outbreak in domestic poultry, regardless of the pathogenicity of the virus.

Why it is Important to know about Avian Influenza

While AI viruses do not usually affect humans, they can occasionally infect persons in close contact with sick birds and poultry. In those rare cases of human infection with AI viruses, there are often dire repercussions. The current H5N1 strain has infected humans and as of March 18, 2008, 373 laboratory-confirmed human H5N1 cases worldwide, including 236 deaths, had been reported to the World Health Organization (WHO). Most human cases have resulted from direct contact with infected poultry, though there is evidence of at least one case of human-to-human transmission of the virus.  The possibility that H5N1 might become more easily transmissible between humans, its high case-fatality rate (60%), the lack of human immunity to this virus, and the ongoing avian outbreaks are of great concern to public health experts, who fear the onset of another influenza.

Why Avian Influenza is a Special Concern for King County.

Several characteristics of King County could make it more vulnerable to an avian influenza outbreak than other parts of the country. First, King County is one of the largest counties in the United States in terms of geography, and has large rural areas in addition to metropolitan centers.  Its vastness and the number of residents with limited English proficiency would require an organized, strategic effort by many government, health, and agricultural agencies to provide the information and education necessary to control an avian influenza outbreak. Secondly, the Seattle municipal code permits backyard poultry (non-commercial poultry, kept on private residential property) in the county’s largest and most densely populated city. In other countries, backyard flocks have played a significant role in the transmission of avian influenza to humans. Finally, King County’s proximity to an international border, the Pacific Flyway (a path followed by migratory birds), and major shipping and transportation routes all increase its exposure to potentially infected birds and humans.

Backyard Poultry in King County: Who Keeps it and Why

snowy chicken coop

It is difficult to accurately quantify the exact number of King County residents who keep backyard poultry. Public Health – Seattle & King County (PHSKC) conducted a community assessment in 2007 to better understand the distribution and uses of backyard poultry and to learn the needs and preferences of people who have frequent contact with poultry. PHSKC attended poultry-related events and interviewed backyard poultry keepers, representatives of public health and state agencies, and members of poultry interest groups.

The assessment suggests that it is likely that hundreds of King County families have poultry on their premises. The majority of these families appear to be native English speakers, and most are well-connected to information about poultry and biosecurity.

Some refugee and immigrant groups in King County also keep backyard poultry. Many of these poultry keepers may have limited English proficiency. PHSKC was especially interested in learning how to best communicate with this group. Therefore, during the community assessment, members of and/or providers for the following ethnic and cultural communities were contacted: Cambodian, Eritrean, Filipino, Hmong, Mexican, Mien, Somali, and Vietnamese. Backyard poultry keeping appeared to be more common among the Hmong and Mien populations of King County than among other refugee and immigrant groups. However, some populations with limited English proficiency who do not keep backyard poultry are involved in food-related and non-food related activities that involve exposure to poultry. Food-related activities include purchasing live chickens from non-commercial sources (e.g., from the back of a truck parked along the side of the road in Seattle, or from a family with a farm in the more rural parts of King County) for slaughter at home or for slaughter at the farm from which it was purchased. Activities thatare not related to food include the ceremonial slaughter of poultry for religious or holiday celebrations (e.g., Hmong New Year) and the use of gamecocks for cockfights in the area.

village roosters

There appears to be a very active cockfighting scene in and around King County. According to key informants, some members of the local Filipino, Mexican, and Vietnamese communities, along with Caucasians, are participants in and/or spectators of cockfights that take place on most weekends in King County and a neighboring county. The birds that are used in cockfights are bred in the United States, and typically come from Arizona, Texas, Alabama, and Kentucky. The gamecock owners and the fight referees are at the greatest risk of exposure to poultry blood and saliva (from mouth-to-beak resuscitation); spectators at these events have less risk of exposure to AI because only owners and referees are allowed to touch the birds. Spectators and participating gamecock owners are men. Women and children do not typically attend these events. Key informants described as many as twenty birds participating on an average night at a local cockfight, and the birds are fitted with steel spurs that increase the risk of exposure to blood. The spurs are cleaned between fights, but they are handled by owners and reused at subsequent fights. When a fight is finished, the dead bird is either cooked and consumed, or buried by its owner. Informants reported that most people involved in the cockfights speak English and can be reached by conventional media. Other methods for reaching this group will be discussed in the next section.

Results of Community Assessment: Exposure to Live Poultry

GroupPets/source of eggsPurchase or acquire live
chickens from non-commercial sources
Slaughter for food or ritualCockfighting
Native English SpeakersXX X
(primarily Mexican)
Vietnamese   X
Somali XX 
Eritrean X  
HmongX X 
Filipino   X

Note: This table reflects known exposure. Though the rates of activity could not be measured, cockfighting is likely engaged in by an extremely small percentage of a particular group’s population.

Where Backyard Poultry Keepers get Information about Poultry

Native English speaking poultry keepers reported getting information about poultry keeping from books, websites, family and friends, and poultry interest groups. Many also take an introductory class about raising urban poultry at Seattle Tilth, a local non-profit that aims to educate people to garden organically, conserve natural resources, and support local food systems. At least 800 people receive Seattle Tilth’s poultry-related electronic newsletter, Scoop from the Coop, which gives some measure of the number of English speaking King County residents who are keeping or are interested in backyard poultry.

The learning preferences of native English speakers and immigrant and refugee groups differ considerably, according to our assessment. The key informants from refugee and immigrant groups said that most of the people they know raise poultry based on prior knowledge of farming in their country of origin. They did not mention use of books or websites for information about poultry keeping, nor did any mention participating in Seattle Tilth classes (which are only offered in English). This means that some of the refugee and immigrant population at higher risk of AI exposure have limited access to information about safe handling of poultry. For example, key informants from the Hmong community who participated in the community assessment suggested that this community has had little training about biosecurity and has poor access to print, radio, and web media. Literacy and language barriers are also significant obstacles to getting prevention messages out to at-risk immigrant and refugee groups.

Reaching Populations at Risk of Exposure to Avian Influenza through Contact with Backyard Poultry

It appears to be rare for native English speaking backyard poultry keepers in King County to slaughter or consume their poultry; therefore, their risk of exposure to poultry blood or bodily fluids is lower than that for limited English proficiency groups. Key informants said that most people involved in cockfighting speak and read English. To get public health messages out to this group they suggested using announcements in local media (including TV, radio, and newspapers), announcements or articles in the local Filipino and Vietnamese language newspapers, and pictorial examples. It should be noted that some members of this at-risk group may be fearful of interacting with government agencies due to the underground and illegal nature of cockfighting.

King County residents who purchase live poultry for slaughter and consumption at home, or who slaughter their own poultry at home, are also at high risk of exposure to AI through contact with the blood and body fluids of infected poultry. Traditional foods that include undercooked or raw poultry can also be a source of exposure, as demonstrated by two human cases of avian influenza in Vietnam that are believed to have been acquired through the consumption of raw blood from an infected duck. Some people who participate in these activities have limited English proficiency, and may speak Hmong, Tigrinya, or Somali as their native language. In order to effectively reach this population, it is important to engage local community leaders to help deliver a public health message; one cannot simply rely on conventional English-language media outlets. For communicating with native Hmong speakers, one could publish flyers in both English and Hmong, but some elderly Hmong refugees are not literate in English or Hmong. However, there are community leaders affiliated with the  that can be reached in the event of an AI outbreak. These leaders can activate an established telephone tree to contact elders in the community. To communicate with Somali and Eritrean refugees, it is important to contact local community-based organizations, such as the Eritrean Community Centers at 2402 E Spruce Street and 1954 S. Massachusetts Street, Seattle, WA; and Somali Community Services of Seattle, 3320 Rainier Ave. S., Seattle, WA. Bilingual flyers could also be printed in English, Tigrinya, and Somali and placed in community centers, shops, and medical offices frequently used by these communities.

Resources and References


  1. Goldrick BA, Goetz AM. Pandemic influenza: what infection control professionals should know. Amer J Infect Control. 2007;35:7-13.
  2. de Jong MD. Avian influenza viruses and pandemic influenza. In: Fong IW & Alibek K, eds. New and Evolving Infections of the 21 st Century. New York, NY: Springer Science and Business Media; 2007:327-368.
  3. World Health Organization. Cumulative number of confirmed H5N1 avian influenza A cases reported to the WHO page. Available online at Accessed on March 18, 2008.
  4. Ungchusak K, Auewarakul P, Dowell SF, et al. Probable person-to-person transmission of avian influenza A (H5N1). N Engl J Med. 2005;352:333-340.
  5. King County Government. About King County page. Available online at Accessed on March 18, 2009