Senegal has among the lowest rates of HIV in Sub-Saharan Africa, at less than one percent. But the most vulnerable group is men who have sex with men (MSM), nearly 22 per cent of whom are HIV-positive. Prisons are high-risk environments for the transmission of the disease, due to the prevalence of hard drugs, violence and sexual relations. There is no mandatory testing in prison, and for those prisoners who, either knowingly or unknowingly, are living with HIV, the stresses of living in prison – including overcrowding, unsanitary conditions, and poor nutrition – mean their health is even more compromised.