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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. What are the symptoms of Bird Flu in birds?The symptoms in birds vary from a mild illness barely noticed (sometimes expressed as ruffled feathers or reduced egg production) to a “highly pathogenic avian influenza”, which is extremely contagious and rapidly fatal for the birds. 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. 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. 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). What are the symptoms of Bird Flu in humans?In those outbreak, patients developed symptoms of fever, sore throat, cough and, in several of the fatal cases, severe respiratory distress secondary to viral pneumonia. Previously healthy adults and children, and some with chronic medical conditions, were affected. 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. Is there a vaccine effective against H5N1 in humans?There is no vaccine effective against H5N1 strain in humans. What medical treatment is recommended for patients with H5N1 avian influenza?Accordingly, two classes of drugs are available. These are the M2 inhibitors (amantadine and rimantadine) and the neuraminidase inhibitors (oseltamivir and zanimivir). These drugs have been licensed for the prevention and treatment of human influenza in some countries, and are thought to be effective regardless of the causative strain. What is ADB’s support to member countries?Following the avian flu outbreak in January 2004, ADB expanded the use of the funds under TA 6108-REG: Emergency Regional Support to Address the Outbreak of Severe Acute Respiratory Syndrome (SARS) for a broad range of activities related to avian flu—these include procurement of equipment and supplies, training, surveillance/monitoring and screening and other public health system capacity needs in relation to the avian flu outbreak. As an initial response to the crisis, on 3 February 2005, ADB’s President has written to affected governments in Cambodia, Indonesia, Lao PDR, Philippines, Thailand, Viet Nam and People’s Republic of China, to express ADB’s concern and willingness to provide assistance. Regional departments and resident missions for affected countries were consulting with counterpart staff to see how ADB might assist, in close partnership with WHO and other concerned agencies. Last year, Cambodia, Viet Nam and Lao PDR availed of the funds to procure personal protective equipment, and conduct training and public awareness campaigns, and the RETA consultants are on call to respond to outbreaks. |
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