From hospitals in Senegal to pharmaceutical companies in South Africa and street sellers in Cameroon, chloroquine has fired hopes of a medicinal fix against a virus that is set to scythe through Africa's poorly protected countries.

Chloroquine and derivatives such as hydroxychloroquine have been used for decades as cheap and safe drugs against malaria, although their effectiveness in this field is now undermined by growing parasite resistance.

Small-scale tests in China and France -- either unpublished or outside the rigorous framework of mainstream drug trials -- suggest that chloroquine reduces virus levels in people with coronavirus.

On March 24, President Donald Trump said chloroquine could be a "gift from God" -- a comment that sparked strident criticism.

Health watchdogs have issued calls for caution until larger clinical trials are carried out, and there have been several recorded deaths from self-medication because of toxic side effects.