At the beginning of the xix th century, the evolution from the miasma theory to the scientific identification of disease vectors for malaria and yellow fever led to the stigmatization of the population who was considered to be responsible for the presence of mosquitoes in Freetown. A double discourse of accusation then appeared: from the colonial authorities towards the African population, but also from the Creoles towards immigrant and neo-urban groups. What was in play was the use of space as well as the frontier between the private, the intimate, and the public.