The World Health Organization has confirmed an outbreak of the deadly Ebola virus in Kasai province, a remote area of the Democratic Republic of the Congo.
But the number of deaths directly related to the virus is unclear.
WHOsays 372 people have fallen ill in the regionsince the end of April,and at least 166 of them have died.
Gregory Hartl, a WHO spokesman for Pandemic Diseases, said health experts don't know how many of these deaths are from Ebola because only five cases of the fatal disease have been confirmed. About 40 more samples are pending.
Hartl said it's possible two or more diseases could be causing these illnesses.
Some of the patients have improved after being given antibiotics, which would have no impact on Ebola, WHO experts said. The experts said that led them to suspect that shigella, a diarrhea-like disease, or typhoid has broken out in the same area. Symptoms for the three diseases are similar in early stages.
"There's no way we can be sure at this time how many cases are shigella and how many cases are Ebola," said Hartl."
Hesaid an emergency response team of clinicians, and water and sanitation experts is going to the area.
Ebola is spread through direct contact with the blood or secretions of an infected person, or objects that have been contaminated with infected secretions.
There is no cure for thehighly contagious disease, which has afatality rate as high as 90 per cent.
Congo's last major Ebola outbreak struck in Kikwit in 1995, killing 245 people. Kikwit is about300 kilometresfrom the site of the current outbreak.