While hundreds of truckers have tested positive for the virus in recent weeks, the drivers say they are being stigmatized and treated like criminals, being detained by governments and slowing cargo traffic to a crawl.

Tanzania closed the border there this week, protesting Kenya’s efforts to re-test all incoming truckers, including those who even had certificates showing they had been tested in the previous 14 days.

We are picking many (truckers) who are positive,” said Pontiano Kaleebu, who heads the Uganda Virus Research Institute, the government testing agency.

Feeling harassed, some truckers refuse to cooperate with authorities, switching off phones or giving the wrong contact address if their sample tests positive, said Ndugu Omogo, head of the Uganda Professional Drivers Network.

Ally Akida Samwel of Tanzania, waiting at the Namanga border post to haul maize to Kenya, said some officials refuse even to touch a trucker’s documents, asking they be read aloud instead.