Under-reporting of human Bird Flu infections poses worldwide threat

Monday, November 21, 2005 

Possible under reporting of bird flu infections in China and other Southeast Asian countries may be promoting an illusory sense that human infections are very limited. Common press reports only describe fewer than 130 people as infected with H5N1 avian flu and that fewer than 70 have died worldwide. Yet, there are enormous problems getting accurate data, especially in a country like China with a population of more than a billion.

"Reporting a suspected bird flu infection in bird or humans is a very unlikely event," said Dr. Shoshana Zimmerman of the eHealth Institute. She is also a founder of www.birdflubeacon.com, a site dedicated to bird flu issues. "There are very few incentives to report, and lots of reasons to refrain from reporting. From the viewpoint of local rural small farmers, there is little to be gained and much to be lost by reporting an infection. The worse threat is that their flocks could be killed, leaving them destitute."

There are many factors which mitigate against reporting bird or human infections of bird flu.

• The deaths of chickens, ducks, and birds are common events for farmer. Even when a large number die at one time they may see no purpose in reporting the deaths.

• When a human dies in locations with little or no medical services, the rural farmer’s priority for discerning the cause of death may be low.

• In rural areas most people are not taken to hospitals when they are sick.

• Bird flu symptoms are not widely known. If the symptoms are not known, they will not be recognized and reports of possible bird or human infections can not be made.

• The expenses required for detection are those of proper collection and shipment of samples to one of approximately 200 laboratories worldwide, as well as the testing procedure that requires a two week period of waiting before results are obtained.

• The lack of incentive for countries to report large scale outbreaks as it may lead to widespread panic and economic loss, as occurred with SARS. These factors can be seen at work in the way that the first bird flu death was reported in China," Dr. Zimmerman stated.

A young woman, Zhou Maoya, died after returning home to the village of Yantan in Annui province to prepare for her wedding. Her family has stated that they did not take her to the hospital because they thought it would not do any good. Officials also note rural Chinese also often cite relatively expensive medical costs as a reason for not seeking treatment when sick.

Although initially authorities attributed her death to pneumonia the resulting political pressure prompted China to invite the World Health Organization to send experts to investigate. The authorities then rescinded the previous position and attributed her death to bird flu based on the similarity of the symptoms that she was reported to exhibit with those of bird flu. The village was quarantined and journalists were denied access. It is not known how many others might be infected in the village. Official announcements were made of plans to vaccinate and cull birds.

A local government official, Fan Qian, told AFP that it was believed Zhou was infected while she was outside of the province.

Fan Tan, a local official, told AFP news that 1,000 birds in Yantan had been culled (killed). Plans were announced to vaccinate 2 million poultry in the area, a huge and difficult task.

Zhang, another official, said authorities had met with all villagers to give them flu vaccinations and to tell them how to protect themselves against the bird flu virus, including not consuming poultry products. It is known that flu vaccinations do not protect against bird flu.

Villagers and local officials minimized the threat. In outlying areas of Yantan, residents said that they did not know of any new outbreaks. Other possible infections have been attributed to similar common causes but there have not been any tests performed validating those attributions.

Fan Litan, a peasant woman from Fantu village, about 2 miles from Yantan, lost many of her ducks, and chickens and also a dog; she has attributed these deaths to the acts of hooligans. She said her family had been extremely frightened when her animals suddenly died. "We were scared to death," said Fan, standing next to a red sign posted on the outside wall of her home that said: "Prevention and control by the masses is basic for people." Fan said ducks and chickens are all healthy but she admitted that she had stopped eating poultry. No testing of these birds has been reported yet.

According to a recent AFP report from Liuchang, 59 miles south of Yantan, the obstacles to identifying infections are enormous.

Like many, one Liuchang villager named Wang Hemin said he was concerned and would keep a closer eye on his ducks and chickens, but felt no immediacy since the infection was not in his province. He learned about bird flu on TV, and is aware that officials have come to his village of 2,700 people to warn residents about the virus. They offered guidelines: they told people that poultry which die suddenly could have contracted bird flu and should not be eaten or sold and that such an incident should also immediately be reported. However, the symptoms of H5N1 bird flu were not directly described.

Residents have not yet been fully informed of what symptoms to look for in ill poultry--they are fever, diarrhea, teary eyes and swelling in the legs of the birds. Though a pledge was made earlier in the week to vaccinate 2 million birds immediately, no bird vaccinations in this area have been reported yet.

In another nearby village, Nazahuang, chickens scuttle in and out of houses. One resident, Fan Jiexu, 73, said no officials had yet warned her village to take precautions. Throughout rural areas, it is customary for chickens to scuttle in and out of homes. Ducks and bird often die and are eaten by villagers when it is believed safe to do so.

China has reported 17 avian flu outbreaks as of this week. Despite the Chinese government issued high alerts, critical information is not being adequately communicated to some rural villages. The size of the poultry population, the common and normal occurrence of poultry death on farms, and status of roughly 70% of the poultry population as being kept in backyards are factors complicating infection control.

The head of World Health Organization's China office, Henk Bekedam, is aware that slow reaction to bird flu threats and difficulty monitoring poultry in the world's most populous country makes control of its spread challenging.

Testing is required to confirm H5N1 virus, and positive test results lead to the killing of nearby flocks. The incentive for many villagers, officials, and governments to minimize reports of H5N1 virus infections and severe medical and economic complications for making confirmations of infection are obstacles opposing complete and full reporting of the spread and infection rates of the virus.

Sources

• "Chinese authorities lock down village after bird flu death" — Yahoo News (AFP), November 18, 2005

• "China's small farms a daunting challenge in bird flu fight" — Yahoo News (AFP), November 19, 2005