France, July 18 -- In Penhalonga, a gold-rich area in eastern Zimbabwe, George Mutsoka woke up one morning suffering from fatigue, a severe headache and joint aches.

The 43-year-old artisanal miner was too weak to work, so he went to rest at his home in Chishakwe village, just outside Zimbabwe's second-largest city, Mutare.

By late afternoon, his situation had deteriorated and he sought help from a village health worker. He tested positive for malaria and the health worker gave him treatment.

"I took the medicine for three days. After a week, I had recovered," he told RFI.

Mutsoka soon returned to Penhalonga, where he works as an informal miner searching for gold. Ideal conditions for mosquitoes

There are thousands of artisanal miner...