International health and agricultural officials in Djibouti are analyzing blood samples from poultry and people in the area near the Somali border, where a child has tested positive for the first case of the deadly bird flu virus to appear in East Africa.
The United Nation's World Health Organization says three other people in a poor, rural village in Djibouti are under observation for possible infection.
All three are believed to have been in close contact with a two-year-old girl, who began to show symptoms of the disease in late April and has tested positive for the deadly H5N1 virus.
The unidentified girl is said to be receiving medical attention and in stable condition.
In remarks broadcast Thursday on state television, Djibouti's health minister said that the girl's family kept chickens and at least three of the birds have also tested positive.
The news of the first outbreak of the bird flu virus in East Africa has renewed fears that wild migratory birds may be playing a role in spreading the virus to domesticated fowl.
In Africa, bird flu has been reported in Nigeria, Cameroon, Niger, Egypt, and now Djibouti. None of these countries are major migratory bird stopover sites and the World Health Organization's team leader for pandemic and outbreak communication, Dick Thompson, says there is still no conclusive evidence that wild birds are carrying the virus to the continent.
"We believe that some of the virus spread has been through migratory birds but we do not really have a firm grip on that," he said. "It is possible that just simply the commercial movement of birds may have played a role. We just do not know."
Thompson says a concerted effort is under way in Djibouti to try to contain the spread of the disease. He says his organization has sent supplies of Tamiflu antiviral medication, which has proven to be effective against the disease. Protective equipment for doctors and nurses has also been delivered to hospitals.
Although H5N1 can cause death in people, transmission from poultry to humans has so far proven to be difficult, usually involving prolonged and intimate contact with infected animals.
The fear is, though, the virus might evolve into a form that can be easily transmitted and provoke a global pandemic.