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Control Measures for Avian Flu

Culling

Once Avian Flu has been detected in live or dead birds, it must be reported to the authorities.  From there, authorities will go about containing the spread of the disease.  The first key to containing the disease or disease outbreak is the culling (killing) of sick and exposed birds.  Culling will prevent the spread of the avian flu to other birds (and farms), and also minimize the risk of human infection. 

When a territory, usually the area where the virus has been detected, has been identified, the authorities will notify all poultry farms, wholesalers, and retailers in the territory of the culling event.  These businesses will usually be compensated.  The territory will be placed under quarantine to restrict movement of live poultry out of the area. 

Culling of poultry will be more extensive at the source where the Flu virus was detected, or source of outbreak.  Culling is performed as humanely as possible, under rigid animal welfare guidelines.  Farms, wholesale markets, and retail outlets will be depopulated in an appropriate manner.     

There are no treatment measures for infected birds.  It appears that it is more important to prevent further spread of the virus rather than saving the bird.  Understandably with humans, it is a different story.

Treatment of Avian Flu in Humans

Anti-viral drugs are given to humans who may be infected with Avian Flu.  These drugs are also used to combat human influenza. 

In the United States, four antiviral medications are approved for treatment of influenza.  These are:

  • Amantadine
  • Rimantadine
  • Oseltamivir
  • Zanamivir (limited supply)

When used for treatment within the first two days of illness, all four antiviral medications are similarly effective in reducing the duration of illness by one or two days.  People who are at high risk of serious complications from Avian flu are given top priority to these medications.  Three of these antiviral medications (amantadine, rimantadine, and oseltamivir) are also approved for prophylaxis (prevention) of influenza. 

The Center of Disease Control recommends that any person experiencing a potentially life-threatening influenza-related illness should be treated with antiviral medications.  Also, any person at high risk for serious complications of influenza and who is within the first 2 days of illness onset should be treated with antiviral medications.  In children, rimantadine is approved for prophylaxis among children aged >1 year and for treatment and prophylaxis of influenza among adults. Although rimantadine is approved only for prophylaxis of influenza among children, certain specialists in the management of influenza consider it appropriate for treatment of influenza among children.  Also available for treatment of children (>1 year) are amantadine and oseltamivir, or zanamivir for children aged over 7 years.

Prevention of Avian Flu

The main key to control the avian flu is through prevention.  Like they say, “an ounce of prevention is worth a pound of cure”. 

Drastic measures are made to prevent the spread of avian flu.  Mass culling of poultry infected, or potentially exposed to the virus is performed to minimize the spread of the virus over areas.  Once an outbreak is controlled, authorities strongly advocate preventative measures to ensure that avian flu does not arise again.  In fact, some embargos may be placed on countries that do not follow these preventative measures. 

Basic bio-security procedures can slow down the spread of the virus and minimize the contamination of poultry with the virus.  Strict on-farm and personal bio-security practices protect poultry operations of any size.  Authorities suggest the following practices to minimize Avian Flu infection and transmission:

  • Keep poultry in closed poultry houses to prevent contamination of wide areas.  This has been problematic in the Avian flu outbreaks in Southeast Asia where many affected farms allowed their poultry to range freely.
  • Keep wild birds and their feces away from poultry and poultry feed.  Wild birds, particularly migratory waterfowl, have been implicated as carriers or reservoirs of the virus.  They are more resistant to the disease, thus they can go harboring and shedding the virus for long periods of time.  Many of the avian flu outbreaks suggest that the point source of infection originated from wild birds passing on the virus to domestic birds. 
  • Seal poultry house attics and cover ventilation openings with screens.
  • Thoroughly and routinely clean all equipment, vehicles, including service vehicles, clothing and footwear before and after coming into contact with poultry.  Birds shed large amounts of virus through their feces and nasal passage (nasal spray, saliva).
  • Ensure proper hygiene practices for all persons coming into contact with poultry.
  • Maintain high sanitation standards in and around poultry houses
  • Isolate or avoid introducing new birds into existing poultry flocks if their health status is unknown.
  • Limit access to poultry houses, including farm workers, feed suppliers, poultry veterinarians, catching crews, sawdust and shavings suppliers, agricultural service personnel and casual visitors.
  • Avoid using water in poultry houses contaminated with feces from wild birds.
  • Ensure thorough cleaning and disinfection for all cages transporting birds.
  • Maintain a log of all visitors coming into contact with poultry.

Avian Flu Vaccinations

In an effort to control widespread infection among poultry, experts from the UN’s Food and Agriculture Organization (FAO), the World Organization for Animal Health (OIE), and the World Health Organization held meetings in February 2004.  The group endorsed the wider use of vaccination in an effort to diminish the impact of avian flu in the future.  However, while vaccination may be a viable option for curbing the spread of influenza in animals, to date there is no H5N1 avian flu vaccine that is licensed by the European Union or the United States for use in humans.

Poultry vaccination is already in use and encouraged in countries such as China and Indonesia, but other countries have challenged vaccination as a control measure.  Some studies have shown that some OIE-approved vaccines take some time to confer immunity to vaccinated birds and may not fully prevent birds from becoming infected or excreting virus.  This has caused considerable controversy over the benefits and risks of vaccination.

Opponents of vaccinations feel that humans can be more at risk being exposed to vaccinated birds that may be healthy-looking and show no symptoms of disease, but may harbor the virus anyways, particularly the lethal H5N1 subtype.  As a result, besides banning all poultry products reporting H5N1 infections, the European Union has implemented a three-year ban on imports from any country where chickens have been vaccinated against avian influenza.  Citing concerns about possible human transmission of H5N1 during vaccination, Thailand, which exports 30% of its poultry to the EU, has refused to vaccinate its flocks and has gone so far as to ban the use of vaccine in the country

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