PREVENTION, CONTROL NOT SO EASY

I talked to a number of experts in order to better understand how difficult the bird flu control and prevention efforts may be. The senior public health official in Chiang Mai believes that it should have been very easy. The key, he says, lies in educating the farmers who should understand the basics of transmission routes and prevention knowledge. For example, these include knowledge about the separation of humans and poultry, wearing gloves when in contact with the poultry and washing hands afterwards, as well as the deep burial of infected birds. However, educating farmers scattered in the vast countryside turns out to be an arduous task. Some farmers deliberately flout the rule of burying infected poultry, and the chances of contracting the virus when slaughtering and preparing the birds for meals are still high. In Thailand, the government plans to educate primary schools pupils on how to live with bird flu.

The senior veterinarian at Beijing Livestock Husbandry and Veterinary Station, Cao Ping, agrees in theory with his Thai counterpart. He believes that the usually lower education levels of farmers prevents them from effectively implementing control and prevention measures – such as disinfection measures that should, if used properly, be the simplest and most effective method. But in practice, the farmers get confused about the exact dilution amount, and too little means futile work, while too much harms both humans and poultry. Cao also points out that some farmers think that spraying disinfectants randomly could do everything when this actually achieves nothing.

Cao also explained in theory why control and prevention proves to be very challenging. There are three key links in infectious animal diseases: the source, routes and vulnerable animals. Effective control of any of the three means elimination of the disease, but the reality is always very tough, if not impossible. The source is sometimes invisible, so how do you locate it? The transmission route is more troublesome. How can you control when the virus spreads in the air? Human can also host the virus. Poultry farms can say no to visitors, but their own workers are not 100 percent safe. This is why some farms demand that their staff not keep any birds at home. Finally, there is the vulnerable animal. Cao joked that you cannot ask poultry farms to get rid of all birds and raise horses to prevent bird flu.

Li Jinxiang, Deputy Director of the Veterinary Bureau of the Ministry of Agriculture, points out that it is tough to deal with wild birds that spread the virus. Migratory birds are a major source of bird flu infection, according to epidemiological research projects conducted by the Ministry of Agriculture and the Chinese Academy of Sciences. Li said that measures can be taken to ensure the separation of humans and poultry, but no one can guarantee that wild birds are virus-free. As long as wild birds carry the virus, they can have opportunities to infect poultry. When outbreaks in poultry take place, birds will excrete large amounts of the virus, and this will be very harmful to public health.

The recent outbreaks in Japan may provide some evidence for the argument that migratory birds are to blame for bird flu. Japan confirmed on Jan.13 that the H5N1 virus hit a poultry farm in the country’s south. A lot of wild ducks were near the farm, and the farm manager said that curtains were used to cover the chicken houses to prevent contact with wild birds. Japanese government officials told the press that wild birds carrying the virus might have dropped their excrement into the chicken houses through the seams of the curtains. If this proves to be true, it only illustrates how difficult bird flu control and prevention effort could be.