Most of Malawi's estimated 7, 500 prisoners live in appalling conditions, often contracting contagious diseases like tuberculosis and scabies.

BBC: Malawi president frees 880 prisoners

The hospital has also been hit by a number of cases of scabies, a skin disorder caused by tiny insects burrowing under the skin.

BBC: Salmonella outbreak hits hospital

Other kinds of vermin such as lice and scabies can get into the mattress as well, although they are less common than mite and bedbug problems.

CNN: Meet the critters inside your mattress

Last year storms prompted an outbreak of scabies.

ECONOMIST: Prisons in Latin America

Specifically they discovered that Pythium ultimum, a fungus that attacks aubergines, peppers, lettuces, tomatoes and cucumbers as seedlings, Clavibacter michiganensis, a bacterium that kills young plants and deforms fruits, and Streptomyces scabies, a second bacterium, which causes potatoes to develop revolting scabs and for which no treatment currently exists, all stopped growing in the presence of the oil.

ECONOMIST: Tobacco extracts protect plants from pests and pathogens