By Cheryl Pellerin
Washington File Staff Writer

Washington – A 35-year-old woman from a remote subdistrict in Indonesia’s West Java province has become that nation’s 59^th case of human infection with the H5N1 avian influenza virus, and its 46^th death.

The Indonesian Ministry of Health confirmed in an August 21 statement from the World Health Organization (WHO) that the woman, from the Cikelet subdistrict, developed symptoms August 8, was hospitalized with severe respiratory disease August 17, and died shortly after admission.

On August 17, the Indonesian Ministry of Health confirmed the country’s 58th case of human infection with the H5N1 avian influenza virus in a 9-year-old girl from a remote village in the Garut district, also in West Java province.

She developed symptoms on August 1, was hospitalized August 14, and died August 15. Recent chicken deaths were reported in her household.

The most recent death in Indonesia brings to 141 the number of human deaths from the H5N1 virus, and to 240 the number of human cases in 10 countries - Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Thailand, Turkey and Vietnam.

THE CIKELET OUTBREAK

A team of WHO experts is in the Cikelet subdistrict investigating the outbreak and monitoring for further cases. Three hamlets are the focus of investigation.

The Cikelet subdistrict consists of 20 isolated hamlets, each with a population of 200-400 residents, many living in large extended families. The hamlets are in a basin surrounded by steep mountains with rocky winding paths that people travel by foot or on horseback.

In this area, mortality from endemic diseases, especially malaria, is common, access to health care is poor and medical records of deaths are insufficient or nonexistent.

In late June, people from the area bought live chickens from an outside market for a religious feast and integrated the birds into local flocks.

Soon after, chickens began dying in large numbers in an outbreak that continued throughout July and the first week of August, spreading from one hamlet to another.

Local residents who had no experience with H5N1 disposed of carcasses in high-risk ways and ate birds that had been sick. Experts think such exposures are the source of infection for most confirmed or suspected cases.

Deaths from respiratory illness occurred in late July and early August, but no samples were taken and medical records are poor.

Some undiagnosed deaths occurred among family members of confirmed cases but the investigation has found no evidence of human-to-human transmission and no evidence that the virus is spreading more easily from birds to humans.

SOUTHERN BALKANS, CAUCASUS

Despite successful efforts to contain the spread of the deadly H5N1 virus, avian flu poses a threat to a growing number of countries, according to the U.N. Food and Agriculture Organization (FAO), which now considers the Caucasus and southern Balkans “high-risk” areas.

“The region is not only a prime resting ground for migratory bird species,” said Juan Lubroth, head of FAO’s Emergency Prevention System for Transboundary Animal Diseases, in an August 21 statement, “but poultry production is mostly characterized by rural and household husbandry with little in terms of biosecurity and strong regulatory inspection.”

The FAO says bird flu has been confirmed in 55 countries in Africa, Asia and Europe, up from 45 four months ago, though the rate of infection among poultry has slowed in most countries.

“We don’t expect to eradicate the H5N1 virus from possible wild bird reservoirs,” said FAO Chief Veterinary Officer Joseph Domenech, “but we can contain and control it fully in the poultry sector, which is the best insurance we have that it will not mutate into a virus that is easily transmissible among humans.”

However, he says in order to control the virus veterinary and laboratory services must be improved in poorer countries, where a general lack of funds hampers public services.

“Just like a chain with a weak link,” he added, “we need to find the weak links in the global effort to contain H5N1 and strengthen them.”

BIRD-TO-HUMAN TRANSMISSION

In the United States, researchers at the Centers for Disease Control and Prevention (CDC) have developed a new research method that may help identify the types of genetic changes necessary for H5N1 to be more easily transmitted among people.

The research was done in collaboration with Centro Nacional de Biotecnologia, Madrid, Spain; the National Institute of Hygiene and Epidemiology, Hanoi, Vietnam; and the Center for Biomedical and Pharmaceutical Research and Development, Ministry of Health, Jakarta, Indonesia, which provided chemicals and viruses for the study.

After developing the research method, CDC scientists used it to investigate the ability of a laboratory-engineered combination of the avian influenza virus and a more common human virus to spread in lab animals.

H5N1 avian influenza viruses do not yet have the property of efficient and sustained human-to-human transmission needed to cause a pandemic among people.

In the CDC experiments, genes from a human influenza virus were added to genes from a strain of the H5N1 avian influenza virus to create new hybrid viruses.

The new viruses were tested in ferrets because their susceptibility to flu is similar to that of humans.

The animals were then placed near each other to see if infected ferrets passed the new virus to uninfected animals and whether they transmitted it more easily than the original H5N1 virus.

In this model, human viruses transmitted efficiently between the ferrets, but avian H5N1 viruses did not. When the hybrid viruses were tested it was found that they also did not pass easily between ferrets.

“This important science has established a new research method to help us learn more - in advance - about the genetic changes that enable new influenza viruses to spread efficiently and in a continuous manner among people,” said CDC Director Dr. Julie Gerberding.

The findings apply only to the specific viruses used in the study, but the research suggests that significant genetic changes in the H5N1 virus will be needed to create a strain that could cause a pandemic.

Future CDC studies will examine whether combining genes from human strains with more recent H5N1 strains makes the new virus more easily transmissible.

To date, the virus only rarely has passed between humans and does not now transmit easily from human to human.

For ongoing coverage, see Bird Flu (Avian Influenza).