May 17, 2006 (CIDRAP News) – World Health Organization officials have confirmed five cases of H5N1 avian influenza in an Indonesian family in North Sumatra, plus a fatal case in a woman from East Java, news services reported today.

Additionally, Indonesia"e;s health ministry said local tests revealed the H5N1 strain in a 12-year-old Jakarta boy who died 4 days ago, according to a Reuters report. This case, however, has yet to be confirmed by the WHO.

The North Sumatra case cluster was first reported by Indonesian officials several days ago, sparking concern about the possibility of person-to-person transmission. In today"e;s reports, officials said the situation was still unclear and investigation was continuing. The WHO had not yet published an online update on the situation at this writing.

WHO officials said four of the five infected family members in North Sumatra have died, according to reports. An Agence France-Presse (AFP) story described them as two males, aged 19 and 17, a 29-year-old woman, and an 18-month-old baby. The fifth person, a 25-year-old man, was recovering, according to AFP.

The case in East Java was in a 38-year-old woman who worked as a caterer in Surabaya before her death last week, according to Reuters. She dealt with live pigs and handled pork in her work, the story said.

The five cases in North Sumatra were confirmed by a WHO-accredited laboratory in Hong Kong, Reuters reported. Tests on a sixth family member, a 10-year-old boy who died, are pending, according to AFP. A 37-year-old woman was the first person in the group to fall ill, but she died without any samples being taken.

WHO spokeswoman Maria Cheng in Geneva said it was "too early to draw any conclusions" about whether the virus has acquired the ability to spread among humans, according to Reuters. "I have not heard any suggestion that the virus is any different," she said.

Another WHO spokeswoman, Sari Setiogi, said the agency was carefully investigating the cases, according to AFP. "The current investigation that we have has no evidence of further spread beyond the cluster, so that"e;s quite good news for us because it tells that the virus is not spreading further," she said.

However, Hong Kong virologist Guan Yi told Reuters that the lag reported between symptom onset in the first victim and in the second wave of victims in the extended family was unusual.

"If they were all infected by the same source," Guan said, "their onset time [of illness] would have been closer. . . . They may have infected one another . . . but we have no evidence."

Unofficially, the six new cases—the North Sumatra family and the caterer in East Java—bring Indonesia"e;s case total to 39 and death toll to 30. The WHO had not yet updated its online case count at this writing.

In Laos, H5N1 was found in a duck on a backyard farm, but it appears to be an isolated case, the UN Food and Agriculture Organization reported in a Reuters news story today.

The duck, found 12 miles south of Vientiane in February by researchers, represents the first case in Laos since an outbreak in poultry in early 2004. There have been no human cases in the country, according to WHO data.