(Associated Press) Attacks on Ebola treatment centers in eastern Congo threaten to reverse the gains being made against the current outbreak of the deadly virus, the director-general of the World Health Organization said Thursday as a fourth assault on a health center was reported.

Nearly 600 people have died from Ebola in the volatile region, making it the second most deadly in history.

Tedros Adhanom Ghebreyesus, who has just returned from a visit to the affected areas in Congo, insisted that efforts to contain Ebola are succeeding. He said that the WHO hopes the outbreak will be brought to an end in the next six months.

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