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Frequently Asked Questions
What is Avian influenza or Bird Flu?Avian influenza, also known as bird flu, is a contagious viral disease, which is caused by viruses that normally infect only birds (including chickens, ducks, geese, quails and wild birds), and less commonly, pigs and other mammals. How is Bird Flu spread?Ducks and other waterfowl act as a reservoir of avian influenza virus by carrying the virus in their intestinal tract and shedding it in their feces. Bird flu viruses are spread to susceptible birds through inhalation of influenza particles in nasal and respiratory secretions and from contact with the feces of infected birds. How Durable is the disease?According to WHO, the virus is killed by heat (56 deg C for 3 hours or 60 deg C for 30 minutes) and common disinfectants, such as formalin and iodine compounds. The virus can survive, at cool temperatures, in contaminated manure for at least three months. In water, the virus can survive for up to four days at 22 deg C and more than 30 days at 0 deg C. For the highly pathogenic form, studies have shown that a single gram of contaminated manure can contain enough viruses to infect 1 million birds. What is the incubation period?The incubation period is usually 3 to 7 days, depending upon the isolate, the dose of inoculum, the species, and age of the bird. How do we control the spread of Bird Flu?Control measures include rapid destruction (“culling” or “stamping out”) of all infected or exposed birds, proper disposal of carcasses, quarantining and rigorous disinfection of farms, biosecurity enhancement, public awareness campaign, surveillance and monitoring, research and development, national and international coordination with agencies, and public health interventions. Another control measure is to restrict movement of live poultry, both within and between countries. What are Asia and Pacific's vulnerabilities?As home to two thirds of the world's poor - and with overcrowded cities, remote rural populations, and inadequate services and infrastructure - the region is ill-equipped to counter the spread of the highly pathogenic H5N1 avian flu virus. In addition, the increased speed and volume of cross border trade and travel brought about by growing social and economic integration has increased the risks and spread of communicable diseases. The problem therefore requires a coordinated response at all levels and a health systems strengthening approach to help prevent and control not only avian influenza, but other communicable diseases as well. Are there public health interventions and safety measures?Public health interventions and safety measures to reduce the risk of avian influenza include:
Are the flu viruses of human and birds the same?In most cases, the influenza viruses that infect birds do not infect humans and vice versa. However, mutations or reassortment of the bird flu virus into new and more aggressive strains occur regularly and have already caused several severe avian flu outbreaks in the past, some of them causing human fatalities. The present avian flu outbreak caused by the H5N1 strain, which first appeared in Hong Kong, China in 1997, started in December 2003 and was identified last year in the People’s Republic of China (PRC), Japan, Lao PDR, Malaysia, South Korea, and 4 countries where it is still present: Cambodia and Indonesia, Thailand and Viet Nam. Visit the WHO site* to know the cumulative number of confirmed human cases of avian influenza A/(H5N1). Why the concern about the current outbreaks?Most of the outbreaks recently reported in Asia have been caused by the highly pathogenic H5N1 strain, which mutates rapidly and has a documented propensity to acquire genes from viruses infecting other animal species. Its ability to cause severe disease and death in humans has now been documented. The greater concern is the possibility that the present situation could give rise to another influenza pandemic in humans. Avian and human influenza viruses can exchange genes when a person is simultaneously infected with viruses from both species. This process of gene swapping inside the human body can give rise to a completely new subtype of the influenza virus to which few, if any, humans would have natural immunity. If the new virus contains sufficient human genes, transmission directly from one person to another (instead of from birds to humans only) can occur. When this happens, the conditions for the start of a new influenza pandemic will have been met. Most alarming would be a situation n which person-to-person transmission resulted in successive generations of severe disease with high mortality. Can a pandemic be averted?No one knows as influenza viruses are highly unstable and their behavior defies prediction.
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