Officials from the World Health Organization are traveling to northern Congo-Brazzaville to investigate reports of an outbreak of the Ebola virus that has killed more than a dozen people.

The World Health Organization's spokesman on infectious diseases, Ian Simpson, says a medical team is headed to the villages of Kele and Mbou, which are about 800 kilometers north of Brazzaville, near the border with Gabon. But Mr. Simpson emphasized that his organization is not yet ready to say an Ebola outbreak has occurred.

"There is no proof at this point that this is an outbreak of Ebola," said Mr. Simpson. "We do know that there have been reports of hemorrhagic fever and that some of the symptoms reported are consistent with hemorrhagic fever."

But health officials in Congo-Brazzaville say they believe it is an Ebola outbreak. Last January, more than two dozen people died of the virus in a nearby village in Gabon before the outbreak was contained.

In Congo-Brazzaville, at least 16 people have died since early last month, displaying classic signs of Ebola infection: high fever and headaches followed by nausea, vomiting, and internal bleeding.

Authorities fear the death toll could be much higher. The villages are in a remote area, and health officials have had difficulty determining how many people have been infected.

Doctors say outbreaks in the region are difficult to contain because tradition requires family members to wash the body of the deceased before burial. The Ebola virus is transmitted through contact with infected blood, saliva, and other bodily fluids.

The virus began spreading among the villagers after they butchered and ate the meat of infected gorillas. More than 80 percent of a clan of gorillas in nearby forests have recently died of Ebola.

During the past 30 years, there have been periodic outbreaks throughout Central and East Africa. But as bad as they are, Ebola and a few other hemorrhagic fevers have been responsible for a tiny number of deaths compared to HIV, the virus that causes AIDS.

Nevertheless, the devastating speed at which Ebola strikes, and its easy transmission from person to person, make the virus one of the most feared in the world. Ebola kills between 50 and 90 percent of those who contract it.