- Lurigancho is the biggest prison in Lima, Peru. It is grossly overcrowded; around 6000 men are detained, although it was built for only 1600 inmates. Inside the perimeter walls the prisoners are in charge. Criminality, the use of illicit drugs, alcoholism and prostitution are rife. Unprotected sex, with prostitutes and amongst the prisoners themselves, is the norm. Furthermore, tatooing and a lack of general (medical) hygiene favour the transmission of HIV. The potential rapid spread of HIV in the prison is also a concern for society. There are strong links between the prison and society. Prisoners are discharged on average after one year and prostitutes from the neighbourhood pay regular visits, at times having 40 contacts a day. Another issue of concern is the spread of tuberculosis, favoured by overcrowding and a lack of rigid control measures. Médecins sans Frontières is starting an HIV prevention project.