The World Health Organization has expressed concern about a new strain of the Ebola virus that has appeared in Uganda’s Bundibugyo District. The last outbreak of the virus was in 2000, when 426 people were diagnosed and 173 died.

The strain is more difficult to find and isolate than those seen previously.

Recent efforts to isolate patients have suffered a setback. “Some people refuse to come out of their home to seek treatment, but our social mobilization team is trying to convince them to come out,” said Samuel Kazinga, who heads the district’s Ebola Taskforce. He described the phenomenon as “psychological” (The Monitor).

Ebola is a highly contagious virus that spreads through contact with bodily fluids of infected persons and by airborne particles. It has no cure or treatment and has a fatality rate of approximately 80%.

Typical symptoms have included fever, muscle pain and nausea. However, patients with the new strain show few or none of these symptoms. While Ebola generally causes massive blood loss through ruptured blood vessels, killing through shock and nonstop internal and external bleeding, the latest strain causes high fever without a great deal of hemorrhaging.

Samples from isolated patients who have died are awaiting screening from the Uganda Virus Research Institute.

Eight health workers—two physicians and six senior clinical officers—contracted Ebola, causing medical personnel to abandon their jobs for fear of infection. However, pathogen experts, international health experts and experienced doctors from international bodies such as WHO, Unicef and Afrinet have been sent to Bundibugyo.