A lack of testing kits that could detect the Bundibugyo strain meant health workers at first struggled to determine an outbreak was underway.
There have also been early indications that the telltale haemorrhaging symptoms seen in the more common Zaire strain have been less frequent in this outbreak, making it easier for medics to confuse the signs with other diseases.
Long-running conflict in north-eastern DRC has added to the difficulties of trying to stop the spread.
“Despite the good progress we have made, we still face major challenges, and the outbreak is continuing to outpace the response,” WHO director-general Tedros Adhanom Ghebreyesus said earlier this week.
The WHO’s Abdirahman Mahamud said health workers continued to face “abduction threats, crimes and being in the wrong place at the wrong time”, citing seven incidents in which they had been targeted.
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