Hundreds of Millions of Dollars Needed to Control Bird Flu

HO CHI MINH CITY, Vietnam, February 28, 2005 (ENS) - The avian influenza virus (H5N1) circulating among poultry, ducks and wildlife in Southeast Asia continues to pose a serious threat to human and animal health, veterinary officers from 28 countries said Friday. The health experts concluded a three day meeting by warning that bird flu poses the “gravest possible danger” of becoming a global pandemic, and hundreds of millions of dollars are needed to control the threat.

Health officials suspect that the viral strain circulating in birds could mutate into another virus transmissible from human to human. If that happens, they say, a global flu pandemic could develop with the potential to cause tens of millions of deaths.

Over 140 delegates from 28 countries and regions as well as international organizations attended the meeting to find ways of halting the disease.

Convened by the UN Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE), the delegates agreed that progress has been made in the early detection of and rapid response to the disease, but they say that prevention and control are now at a critical time and stronger joint efforts are needed in the battle.

Kampung chickens just purchased from market on a farm in Bandar Lampung, Indonesia (Photo by Ian Douglas courtesy FAO)

They estimated that $100 million in assistance is needed to upgrade veterinary services and laboratories to improve virus detection and its ultimate eradication, according to a final FAO report on the meeting.

Several hundred million dollars would be required to finance the restocking of infected poultry flocks and to restructure the whole sector, they suggested.

Since the epidemic of highly pathogenic avian influenza caused by H5N1 first emerged in North Korea in mid-December 2003, it has spread to eight Asian countries, and hundreds of millions of birds have been culled at great cost to poultry producers in the region.

The disease has crossed the species barrier with at least 55 human cases reported, according to the World Health Organization. Of the 55 cases reported, 42 people have died in Vietnam, Thailand and Cambodia.

In January 2004 laboratory tests confirmed the presence of H5N1 avian influenza virus in human cases of severe respiratory disease in the northern part of Vietnam.

As the conference concluded Friday, news came that a 21 year old man from Vietnam's northern Thai Binh province was diagnosed with the avian influenza (H5N1) virus infection, and his younger sister also is suspected of having the virus, reported the local newspaper "Youth." The young man is the third case of bird flu infection diagnosed in Thai Binh this year. Vietnam has experienced three outbreaks of bird flu in humans in the past 18 months, and 32 people have died.

The bird flu virus does not respect borders and needs a strong regional response, the veterinary officers said. Regional cooperation networks recently established by the FAO should be extended, they said, but without proper funding, these networks will cease their activities within the next six months.

Delegates called upon the global community to help with the financing of these costly but essential efforts.

The conference delegates recognized the link between farming systems and the spread of the virus, especially the proximity between chickens and ducks in many backyard households that appears to be contributing to the circulation of the disease.

In addition, the movement and marketing of live animals, not controlled by veterinarians, are a major cause for spreading the disease, they said.

Pigs, ducks and chickens share a farmyard in Laos, a situation that veterinarians say spreads avian flu. (Photo by Ray Webb courtesy FAO)

To protect humans by minimizing the risk of virus transmission between species, delegates recommended that these farmers segregate chickens, ducks, and other animals such as pigs from one another. They said contact between these animals and humans must be kept to a minimum.

The meeting agreed that vaccines can be a strong weapon in the fight against the disease in poultry, and that the possibility of vaccinating ducks should be explored.

Still, delegates acknowledged the need to further study conditions in which vaccines can be delivered with minimum risk to human health.

The U.S. government is preparing to test an avian flu vaccine and stockpiling both vaccine and antiviral drugs as the threat grows that the deadly strain of bird flu will begin spreading from Asia.

Two million doses of vaccine are being stored in bulk form for possible emergency use and to test whether it maintains its potency, officials said Thursday

The new vaccine was prepared in two different concentrations of 4,000 doses each, and it is nearly ready to be shipped to the National Institute for Allergy and Infectious Diseases (NIAID) for clinical trials, said Len Lavenda, a spokesman for the vaccine manufacturer Sanofi Pasteur.

NIAID Director Dr Anthony Fauci said the vaccine will be tested at centers in Rochester, New York, St Louis and in Maryland and Texas to ensure its safety and to determine the proper dosage for the elderly, children and healthy young people.

Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention, told reporters on February 22 during a talk at the National Press Club in Washington, DC, that “it is a worrisome situation,” though she also said the United States “is not immediately on the brink of an avian flu epidemic.”

But the disease may already be more widespread in humans than has previously been recognized. An article published in the journal "Nature" on Thursday indicates that some Vietnamese doctors have been incorrectly clearing patients of the H5N1 virus when they were actually infected.

Reanalysis of samples from Vietnamese patients with flu-like symptoms at the National Institute of Infectious Diseases in Tokyo has shown that some people originally declared free of avian influenza did carry the H5N1 virus.

The article by David Cyranoski, entitled "Tests in Tokyo reveal flaws in Viet Nam's bird flu surveillance," could prompt experts to re-evaluate the severity of the avian flu in humans. To date, the death rate for infected patients has been high - 10 of the 11 cases identified in Vietnam since December 2004 have died. But if more cases exist although unidentified, the mortality rate could be lower, but the disease could be recognized as more prevalent.

Workers disinfect a poultry farm in Cambodia after avian flu was discovered there in 2004. (Photo by Stéphanie Desveaux courtesy FAO)

Migratory waterfowl, especially wild ducks, are the natural reservoir of avian influenza viruses, and these birds are also the most resistant to infection, according to the World Health Organization (WHO). Domestic poultry, including chickens and turkeys, are particularly susceptible to epidemics of rapidly fatal influenza.

Direct or indirect contact of domestic flocks with wild migratory waterfowl has been implicated as a frequent cause of epidemics. Live bird markets have also played a role in the spread of epidemics.

Influenza A viruses, such as H5N1 virus, are particularly dangerous, health experts say, because they can swap, or reassort, genetic materials and merge. This reassortment process, known as antigenic shift, results in a new subtype different from both parent viruses.

"As populations will have no immunity to the new subtype, and as no existing vaccines can confer protection, antigenic shift has historically resulted in highly lethal pandemics," WHO says.

For this to happen, the novel subtype needs to have genes from human influenza viruses that make it readily transmissible from person to person for a sustainable period.

Conditions favorable for the emergence of antigenic shift are thought to involve humans living close to domestic poultry and pigs. Because pigs are susceptible to infection with both avian and mammalian viruses, including human strains, they can serve as what the WHO calls a “mixing vessel" for the "scrambling of genetic material from human and avian viruses," resulting in the emergence of a new viral subtype.

But, WHO says, evidence is mounting that, for at least some of the 15 avian influenza virus subtypes circulating in bird populations, "humans themselves can serve as the mixing vessel."