Bird Flu (Avian Influenza)

There has been much concern in the news about bird flu or avian influenza. Influenza viruses that infect birds are called "avian influenza viruses." The Centers for Disease Control and Prevention (CDC) say these viruses are genetically different from influenza viruses that normally infect people. (Read about "Influenza") Avian influenza viruses can be classified into "low pathogenic" and "highly pathogenic" forms based on the severity of the illness they cause in poultry.

Avian influenza A viruses can infect several animal species, including birds, pigs, horses, seals and whales. Birds are an especially important species because all known subtypes of influenza A viruses circulate among wild birds, which are considered the natural hosts for influenza A viruses. Birds that are infected with avian influenza viruses shed virus in saliva, nasal secretions and feces. Disease spreads when susceptible birds have contact with contaminated excretions.

Type A influenza viruses do not usually infect humans, according to CDC. There have however, been an increasing number of cases of human infections and outbreaks of avian influenza reported in recent years. Southeast Asia has been the area most affected. It is believed that most cases of avian influenza infection in humans have resulted from contact with infected poultry or contaminated surfaces.

Public health authorities monitor outbreaks of avian influenza closely because of concerns about the potential for more widespread infection in the human population. CDC says so far, human infection with avian influenza viruses, detected in recent years, has not resulted in sustained human-to-human transmission, meaning any kind of epidemic. However, because influenza viruses can change and gain the ability to spread easily between people, monitoring for human infection and person-to-person transmission is important.

Related Information:

    Microorganisms

    Animal & Insect Borne Diseases

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