Jan 5, 2006 (CIDRAP News) – The sister of a Turkish teenage boy who died of avian influenza Jan 1 has succumbed to the same disease, the World Health Organization (WHO) announced today.

Turkish officials reported the two cases yesterday, marking the first human cases of avian flu outside East Asia.

The WHO statement said Turkey "has confirmed its first two cases of human infection with avian influenza caused by the H5 virus subtype."

The two victims were 14-year-old Mohammed Ali Kocyigit and his 15-year-old sister Fatma, according to an Agence France-Presse (AFP) report today. They lived in the town of Dobubayazit in Agri province, which borders on Iran and Armenia, the WHO said.

Nine other patients from Dogubayazit have been hospitalized with suspected avian flu in Van province, where the two victims were treated, the WHO said. Most are children between the ages of 6 and 15; two of them are siblings of the two patients who died.

One of the surviving Kocyigit children was in critical condition today, according to AFP and Reuters reports.

The WHO statement did not say that the virus was confirmed to be H5N1, but it implied there was little doubt. "The cases in Turkey bring the number of affected countries to six, from which 144 cases [of H5N1 avian flu] have now been reported," the agency said. The statement said patient samples have been sent to the United Kingdom for further analysis.

Yesterday Michael T. Osterholm, director of the University of Minnesota Center for Infectious Disease Research and Policy, publisher of this Web site, said he was told that tests had detected the H5N1 virus. Also, a WHO spokeswoman quoted in today"e;s AFP report said H5N1 was the likely pathogen.

At Turkey"e;s request, a team of experts from the WHO and European agencies was heading to Turkey today to help investigate the cases, the WHO said.

Echoing previous reports, the agency said it appears that the children fell ill after contact with chickens. "Although no poultry outbreak has been officially reported in the district, a confirmed outbreak of H5N1 avian influenza in chickens and ducks was reported on 27 December in the adjacent province of Igdir," the WHO said.

Turkish authorities have said the Dogubayazit area has been quarantined, with no people or animals allowed to move in or out, the WHO reported. Culling of poultry was reported to be under way.

Turkey"e;s first outbreak of H5N1 in poultry was reported in October in the northwestern part of the country. The WHO said migratory birds are believed to have introduced the virus in Turkey.