Control measures in birds

What are the control measures in birds?

Are the right control measures being applied?

What are the consequences of outbreaks in poultry?

What is the risk of catching avian influenza if I keep back yard chickens or caged birds and what precautions can I take?

How do outbreaks of avian influenza spread within a country?

Could the outbreak of HPAI spread through birds in the UK?

Is there any risk of avian influenza from feathers imported from affected countries?

 

 

What are the control measures in birds?

The most important control measures are rapid destruction ("culling" or "stamping out") of all infected or exposed birds, proper disposal of carcasses, and the quarantining and rigorous disinfection of farms and poultry markets. It should be noted that a large outbreak of highly pathogenic avian influenza in the Netherlands in 2003 was completely eradicated by poultry culling and limiting movement of commercial poultry.

Vaccination of poultry has also been successfully used but is impractical outside of large scale commercial settings, too costly to implement in resource poor countries, and the vaccine requires regular updating. In addition vaccinating large flocks of chickens may cause highly pathogenic avian influenza virus to colonize them without causing any illness in the birds. The avian flu virus is killed by heat and common disinfectants, such as formalin and iodine compounds. Thorough cooking of any poultry meat will destroy the virus.

 

Are the right control measures being applied?

In some cases, yes. Japan and the Republic of Korea for example appear to have controlled outbreaks in poultry, quickly and safely. Studies of workers involved in culling operations have been conducted, and no cases of human infection have been detected. The situation in other countries is more problematic.

The World Health Organization (WHO) is fully aware that governments in several countries with serious poultry outbreaks do not have the resources needed to introduce recommended protective measures for cullers or carry out the very rapid destruction of poultry flocks. In some of these countries, the practice of raising poultry on backyard farms in remote rural areas, which may not be registered with agricultural authorities, further complicates rapid and systematic elimination of the animal reservoir.

WHO, the United Nations Food and Agriculture Organization (FAO), and the World Organization for Animal Health (OIE) have jointly issued an urgent appeal to the international community to make adequate resources and other forms of support available quickly in the interest of protecting international public health.

 

What are the consequences of outbreaks in poultry?

Outbreaks of avian influenza, especially the highly pathogenic form, can be devastating for the poultry industry and for farmers. For example, an outbreak of highly pathogenic avian influenza in the USA in 1983-84, largely confined to the state of Pennsylvania, resulted in the destruction of more than 17 million birds at a cost of nearly US$ 65 million. Economic consequences can be especially devastating in developing countries where poultry raising is an important source of income - and of food - for impoverished rural farmers and their families.

When outbreaks become widespread within a country, control can be extremely difficult. For example, an outbreak that began in Mexico in 1992 was not completely controlled until 1995.

For these reasons, government authorities usually undertake aggressive emergency control measures as soon as an outbreak is detected.

 

What is the risk of catching avian influenza if I keep back yard chickens or caged birds and what precautions can I take?

HPAI H5N1 can be spread to humans through close contact with live and dead infected birds; the virus is shed in the faeces of such birds, so contact with faeces is a possible transmission route. Where possible, domestic birds should be kept in covered accommodation to avoid contact with wild birds. The practice of thoroughly washing hands with soap and water (followed by drying) after contact with wild or domestic birds and ensuring any animal killed for meat is cooked thoroughly will help minimise the risk of infection from other diseases. More information is available from Defra (external website).

 

How do outbreaks of avian influenza spread within a country?

Within a country, the disease spreads easily from farm to farm. Large amounts of virus are secreted in bird droppings, contaminated dust and soil. Contaminated equipment, vehicles, feed, cages or clothing - especially shoes - can carry the virus from farm to farm. The virus can also be carried on the feet and bodies of animals, such as rodents, which act as mechanical vectors for spreading the disease.

Droppings from infected wild birds can introduce the virus into both commercial and backyard poultry flocks. The risk that infection will be transmitted from wild birds to domestic poultry is greatest where domestic birds roam freely, share a water supply with wild birds, or use a water supply that might become contaminated by droppings from infected wild-bird carriers.

So called 'wet markets', where live birds are sold under crowded and sometimes unsanitary conditions, can be another source of spread.

 

Could the outbreak of HPAI spread through birds in the UK?

The disease can spread from country to country through international trade in live poultry. Migratory birds, including waterfowl, sea birds, and shore birds, can carry the virus for long distances and are implicated in the international spread of highly pathogenic avian influenza. Migratory waterfowl - most notably wild ducks - are the natural reservoir of bird flu viruses, and these birds are also the most resistant to infection. They can carry the virus over great distances, and excrete it in their droppings, yet develop only mild and short-lived illness themselves.

Domestic ducks, however, are susceptible to lethal infections, as are turkeys, geese, and several other species raised on commercial or backyard farms.

 

Is there any risk of avian influenza from feathers imported from affected countries?

The importation of feathers from affected countries into the UK is only permissible if strict cleaning methods (recommended by international experts) have been undertaken prior to import. All consignments of processed feathers from affected countries must also be accompanied by commercial documentation stating that the required cleaning has already taken place. The risk to UK residents from imported feathers is therefore considered negligible.

Feathers exported in a dirty (unprocessed) state would be highly susceptible to deterioration in transit to the UK such that they would be foul-smelling, unsuitable for use in commercial bedding, upholstery or clothing, and easily detectable by smell, sight or both. China in particular has invested massively in bulk feather processing facilities; therefore illegal importation or cleaning practices are judged to be extremely unlikely.

Last reviewed: 13 August 2008