Mar 18, 2008 – ATLANTA (CIDRAP News) – More than 10 years after the first appearance of avian influenza H5N1, it is time to acknowledge that the virus has become entrenched in many areas and to begin grappling with its social and economic effects, leading researchers said at a scientific meeting.
Speaking at the biennial International Conference on Emerging Infectious Diseases, senior animal-health scientists urged their human-health colleagues to focus on the many non-science issues—from agricultural traditions to food needs to gender relations—that are complicating avian flu control.
H5N1's potential for causing a human pandemic has understandably been the major focus of research, the scientists acknowledged. But "for every human being infected, there is at least 1 million animals infected—and that is probably an underestimate," Dr. Ilaria Capua, the head of virology at Italy's Istituto Zooprofilattico Sperimentale delle Venezie, said Tuesday morning. "The veterinary community . . . have never before faced a challenge this big."
Most of those animals are in the developing world, and the majority are owned by small farmers and households. So the basic outbreak-control measures of culling infected birds and closing live-bird markets pose immediate threats to the income and nutrition of individual families.
"This disease represents a food security issue," Capua said. "It is destroying the livelihood of rural communities."
Control programs have bumped up against an array of unforeseen difficulties. In Southeast Asia, Capua said, experts hoping to train farmers in biosecurity have been frustrated by loyalty to traditional practices that confine different species such as chickens, ducks, and pigs in the same space.
In Africa, said Dr. Alejandro Thiermann, special advisor to the director-general of the World Organization for Animal Health, programs that offer compensation to farmers who surrender birds for slaughter have been tripped up by ignorance of family economics. Villagers who raise and sell chickens tend to be women, he said—and they have held their birds out from surrender programs because compensation is paid to the heads of households, who are men.
The economic repercussions reach from the micro level of village markets to the macro level of national economies and back, Thiermann said. Fearing the importation of H5N1 flu, some countries have banned imports of chicken produced in affected countries, even when the disease has been found in wild birds rather than poultry. The resulting collapse in trade within a country depresses the prices that small-scale growers earn and makes them less willing to report disease outbreaks.
The problem has proved so significant that new provisions governing avian flu-related trade restrictions are being added to the Animal Terrestrial Code, an international treaty governing veterinary health, said Thiermann, who serves as the Code's secretary.
The adoption of widespread poultry vaccination, one of the chief tools for controlling avian flu, also illustrates the complexity of integrating flu control into cultures and economies, said Dr. Les Sims of Australia's Asia-Pacific Veterinary Information Services.
Stringent vaccination has successfully controlled avian flu in Hong Kong since late 2003, Sims said—but Hong Kong is "small and rich" and its results have not been replicated in any other country where avian flu is endemic.
China, which at any one time houses 600 million ducks and more than 4 billion chickens, has intermittently suppressed disease in its birds but may not be monitoring outbreaks closely, he said. Indonesia, the country with the most human deaths, has faced significant problems delivering the vaccine to far-flung islands and negotiating the relationships with powerful provincial authorities who may not support vaccination as strongly as the national government does.
Even Vietnam, which in 2005 and 2006 had significant success controlling avian flu through vaccination and restrictions on bird raising and movement, experienced fresh outbreaks in 2007 and this year.
"We knew that mass vaccination would be very difficult to sustain, both the financial cost to the government and the enthusiasm of the people to go out and support it," Sims said. "The problems that are occurring in Vietnam now are largely ones that appear to be due to farmers not having their birds vaccinated rather than to vaccine failure."
Successful avian flu control will require attention to these and other "last-mile" difficulties that are not usually the province of virologists or human-health planners, the scientists cautioned.
"Let us put ourselves in the real world and try to find solutions that are applicable and sustainable," Capua said.