Unknown Illness Kills Dozens in Congo as Experts Clash on Cause

The mystery behind an unknown illness that has killed dozens in the Democratic Republic of Congo just 48 hours after they first showed symptoms deepened after the World Health Organization on Friday offered a new theory that seemingly contradicts African medical experts.

At least 60 people have died and more than 1,000 have been sickened in Congo’s Équateur Province by the illness, which is characterized by “fever, headache, chills, sweating, stiff neck, muscle aches, multiple joint pain and body aches, a runny or bleeding nose, cough, vomiting and diarrhea,” according to the latest W.H.O. report issued on Thursday.

At a news conference in London on Friday, Dr. Michael Ryan, director of emergencies for the W.HO., said the illnesses were most likely caused by poisoning, contradicting a theory proposed on Thursday by experts at the African Centres for Disease Control and Prevention who speculated malaria was to blame.

“Based on onset of symptomatology to death,” Dr. Ryan said, “it looks and appears very much more like a toxic type event, either from a biologic perspective like a meningitis or from a chemical exposure.” He added that there was “a very strong level of suspicion,” that the poisoning was related to “a water source.”

Investigators determined the initial outbreak began in the northwestern village of Boloko before spreading to nearby Danda village, the W.H.O. said. A second, larger outbreak occurred in Bomate village.

Preliminary investigations traced the outbreak to three children who in January ate a bat and died. Before death, the children had all bled from their noses and vomited blood.