March 10 (Bloomberg) -- Bird flu's spread in Germany to a second animal species heightens concern the lethal virus may be adapting to mammals, including people, scientists said. In Azerbaijan, 11 possible human cases are being investigated.

German officials confirmed H5N1 infection in a stone marten, a type of weasel, which showed severe illness when found on the Baltic island of Ruegen on March 2, the World Health Organization said yesterday. As with three dead domestic cats found on the island, the marten is presumed to have contracted the virus from feeding on an infected bird, WHO said.

``It's a property of this virus that it can go into these animals,'' Hugh Pennington, who has studied viruses for more than 40 years, said yesterday by telephone from Aberdeen, Scotland. ``One just has to watch and see what happens because the virus has the property to evolve.''

The rate of H5N1 infections in humans is increasing as the virus spreads to more parts of Asia, Africa, Europe and the Middle East. Georgia yesterday became the 23rd country to report an initial outbreak in birds since February.

The virus has killed at least 97 of 176 people infected since late 2003, including a 3-year-old boy who died last week in Indonesia.

Samples from the boy, from Semarang in central Java, were positive for the H5N1 strain in tests verified by the U.S. Centers for Disease Control and Prevention, Hariadi Wibisono, director of vector-borne disease control with the Health Ministry in Jakarta, said today.

Azerbaijan Patients

Eleven suspected cases, three of them fatal, are under investigation in the former Soviet republic of Azerbaijan, Agence France-Presse reported yesterday, citing World Health Organization spokeswoman Maria Cheng.

The patients in Azerbaijan, who include eight members of a single family, all came from the same village near the capital Baku, AFP reported. The virus infected poultry in neighboring areas and flocks belonging to the patients were sickened, the cause of which hasn't yet been confirmed, the report said.

In almost all human cases, infection was caused by close contact with sick or dead birds, such as children playing with them, or adults butchering them or taking off the feathers, Lee Jong Wook, director general of the WHO, said in a speech yesterday in the Kenyan capital, Nairobi.

The virus is reported to have infected an average of three people a week this year, killing an average of two a week. Last year, 23 cases, including 14 fatalities, were reported in the first 10 weeks. Indonesia, with nine confirmed fatalities, and China, with five, reported the highest number of deaths this year.

Drug Option

Laboratory tests on the generic drug amantadine showed it is effective in stopping the replication of strains of H5N1 isolated in Indonesia and China, indicating the older class of antiviral medicine may be a cheaper option to Roche Holding AG's Tamiflu in fighting the virus in humans, the WHO's Cheng said yesterday.

China's Health Ministry today called for heightened regional efforts to prevent domestic fowl from coming into contact with migratory birds, as a precaution against avian flu in the approaching spring months when the wild birds travel.

Health officials in regions through which migratory birds pass are stepping up efforts to reduce the birds' contact with domestic poultry, ministry spokesman Mao Qun'an said, without elaborating. Human cases of the deadly H5N1 strain of bird flu in areas where no poultry outbreaks have occurred may indicate contact with migratory birds is the source of infection, he said.

Some residents of Indonesia's capital, Jakarta, moved their pet birds to a nearby resort area to avoid house checks for diseased fowl, Koran Tempo reported. The checks are part of the Indonesian government's program to slow the virus's spread.

Georgia Swans

Nine swans found dead on a lake in the former Soviet republic of Georgia tested positive for an H5 subtype of avian flu, a government official said in a statement yesterday to the World Organization for Animal Health. About 1,700 domestic fowl were culled in five nearby villages to contain the spread.

Since Feb. 16, German authorities have confirmed H5N1 infection in 125 wild swans, ducks, geese, and birds of prey on Ruegen Island, pointing to considerable opportunities for exposure to occur in small mammals that feed on birds, the WHO said yesterday in a statement on its Web site.

In July, tests on three rare Owston's palm civets that died in captivity in Vietnam found H5N1 infection, marking the first known infection in this mammalian species. Large cats, including tigers and leopards, kept in capacity and fed on infected poultry carcasses, have also been infected and developed severe disease.

To contact the reporter on this story: Jason Gale in Singapore at j.gale@bloomberg.net

Last Updated: March 10, 2006 01:59 EST