As clouds gather and humidity rises across west Africa, whose annual rains bring an uptick of deadly, malaria-carrying mosquitoes, Musa Adamu Ibrahim, a nurse, is sitting at home, unemployed.

In Nigeria — home to 30% of the world's annual 600,000 malaria deaths — clinics that once served 300 people a day in the conflict-hit Borno state have abruptly shut down, Ibrahim and other laid-off workers said, following the withdrawal of American funding by President Donald Trump.

"The clinics have been closed and (there are) no more free drugs or mosquito nets," said Ibrahim.