Asian Bird Flu Flare Up Kills Mother and Daughter

BANGKOK, Thailand, September 30, 2004 (ENS) - Thai health officials are investigating the first possible human-to-human transmission of a highly virulent form of avian influenza, and countries across Asia are scrambling to prepare for another outbreak of the deadly virus. An 11 year old girl and her mother both died since early September. Officials believe the mother was infected while caring for her daughter, and that this is a probable case of human-to-human transmission.

"Such a situation would be cause for alarm, as it might signal the start of an influenza pandemic," warned the Ministry of Public Health in Thailand. Still, evidence to date indicates that transmission of the virus among humans has been limited to family members and that no wider transmission in the community has occurred.

Altogether, Thailand has reported 15 cases, of which 10 were fatal, since the first human cases were detected in January of this year. Health officials confirm that these people were infected with the avian influenza A (H5N1) virus, the same viral strain that caused 23 deaths and the slaughter of at least 100 million birds in an outbreak across Asia last winter and spring.


Infected chickens are consumed in fire to keep the virus from spreading. (Photo courtesy CIAI)
The avian influenza epidemic in Asia is a "crisis of global importance" and will continue to demand the attention of the international community, the UN Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE) are warning.

Recent outbreaks in China, Vietnam, Cambodia, Malaysia and Thailand show that the virus continues to circulate in the region and will not probably be eradicated in the near future, the two organizations said in a joint statement on Monday.

On Monday, the Ministry of Health of Vietnam has confirmed that the death of a 14 month old boy early this month was caused by the same viral strain. This is the third death from the virus in Vietnam since August. The baby in Hanoi had typical symptoms of avian influenza virus infection, including fever and cough.

China has required all localities to strengthen preventive efforts against a possible outbreak of the highly pathogenic bird flu, during autumn 2004 and winter 2005, according to a new circular issued by the Ministry of Agriculture.

"Since the autumn and winter period is a key period for birds to migrate, the bird flu is quite likely to break at any time," warns the circular, which cites the ongoing bird flu in other Asian countries as a threat to China.


The H5N1 strain of avian influenza under a microscope (Photo courtesy CSIRO)
More research is urgently needed as the role of wildlife, domestic ducks and pigs in transmitting the virus among animals is still not fully understood, the FAO and OIE warned. "A permanent threat to animal and human health continues to exist," they said.

While much progress has been made in early detection and reaction, countries still need to step up proactive surveillance and control measures. Major investments are required to strengthen veterinary services, in particular for surveillance, early warning, detection, reporting and response and for the rehabilitation and restructuring of the poultry sector, the agencies said.

The newly published FAO Recommendations on the Prevention, Control and Eradication of Highly Pathogenic Avian Influenza in Asia, prepared in close collaboration with the OIE, review the factors that should be taken into account in designing and implementing control programs and explain how countries can adopt a strategy appropriate to their individual situation.

In response to recent controversies on vaccination against bird flu, the two agenices reiterated that the slaughter of infected animals is the best way of controlling and ultimately stamping out the disease.

But officials acknowledged that this policy may not be practical or adequate in certain countries because of social and economic reasons or because of high viral challenge due to infection in villages, wild birds or domestic waterfowl. In such cases, countries wishing to eradicate the disease may choose to use vaccination as a complementary measure to the stamping out policy.


Sick chickens on an Indonesian farm (Photo courtesy FAO)
China's bird flu control policy is based mainly upon mass preventative vaccination. "Authorities should also prepare and improve their emergency plans and ready vaccine and sterilizing drugs," says the Ministry of Agriculture circular.

The two agencies stressed that vaccines, if used, should be produced in accordance with the international guidelines prescribed in the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.

The OIE Terrestrial Code states that a country may be considered free from highly pathogenic avian influenza based on the absence of virus irrespective of whether vaccination has been carried out. The two organizations confirmed that the use of vaccines does not imply automatic loss of export markets.

It has been shown that the use of such vaccines does not only protect healthy birds from disease but also reduces the load of viruses excreted by infected birds and cuts the likelihood of transmission of the virus to other birds and to humans.

The decision on whether to use vaccines has to be made by each country based on its own situation, the two agencies said.


Workers disinfect a Cambodian poultry farm (Photo courtesy FAO)
The factors countries should consider in making their decision include their ability to detect and react to the disease as early as possible and the need for transparent and timely notification. This will have to be supported by a good institutional framework and sound legislation underpinning veterinary services.

Any vaccination strategy should be developed in consultation with all stakeholders, including the private sector. The types of poultry and production sectors to be vaccinated must be determined and clearly documented. Infected poultry and those in contact with the virus should not be vaccinated.

The two agencies said vaccination should be carried out under the supervision of official veterinary services and be accompanied by a parallel surveillance strategy.

This would include the capacity of the veterinary services to identify and monitor the circulating virus as well as the response to vaccination, by means including the use of non-vaccinated sentinel birds and the application of serological tests capable of differentiating infected from vaccinated animals.

The World Health Organization's Southeast Asia Regional Office says, "The risk of emergence of a new influenza virus due to genetic modifications, which could trigger an outbreak with pandemic potential, remains real as long as the avian influenza virus continues to circulate in the environment."

It appears that the virus will continue to stay in the environment in the foreseeable future so WHO officials emphasized the need for enhanced and sustained surveillance.