The World Health Organization says it is sending a team of international experts to Iraq to investigate how a 15-year-old girl became ill and died of avian flu. The World Health Organization says it is concerned that bad security in Iraq makes it difficult to move around and properly monitor the presence of bird flu.

The World Health Organization says the team of experts will travel this week to Sulaimaniyah in northern Iraq where the cases of bird flu have been detected. The Iraqi Ministry of Health has confirmed that a 15-year-old girl who died on January 17 was infected with the H5N1 bird flu virus.

WHO spokesman Ian Simpson says samples from the dead girl, as well as from her uncle who died of a severe respiratory illness on January 27, and a suspected third case are being tested in a laboratory in London for the presence of bird flu.

He says the international experts will try to track down the source of the disease. He says they will investigate how the three people could have been exposed and infected by bird flu.

"Looking at, for example, the way that chickens are raised, which is an extremely serious issue in all the countries which have outbreaks of avian influenza," he said. "Because where there is very close contact, particularly between children and chickens, it is clear that children are at great risk of exposure."

An Iraqi villager herds his ducks in Raniya, 350 kilometers north of Baghdad

Sulaimaniyah is near the Turkish border where an avian flu outbreak infected 12 people, including four that died of the disease. Iraq is the seventh country to report human H5N1 infection in the current outbreak. The first human case occurred in Vietnam in December 2003. WHO figures show since then, there have been 160 cases of bird flu, of whom 85 people died, most in Asian countries.

Simpson says the surveillance system in Iraq is weak because security problems make it difficult to move around and get accurate information.

"There clearly is a surveillance system," he said. "At a basic level it is working because it picked up this case. But, we do have concerns about how good the surveillance system is and we particularly have concerns, as in the case of Turkey, about the surveillance system of animals. You can imagine, if the human health surveillance system is relatively basic, then the system for animals surveillance is likely to be even more so."

The World Health Organization warns an avian influenza pandemic could potentially kill millions of people. The number of human cases has been low, but the U.N. agency says that situation could rapidly change if the H5N1 virus in birds mutates into a form that could spread the disease from human to human.