Evaluating Light Trap Efficiency and Leishmania Infection Status in Sand Fly Species from Kousseri, Northern Cameroon

The role of sand flies in Leishmania transmission in Cameroon remains understudied, limiting the implementation of a national control program. To address this, a one-year survey, from September 2020 to August 2021, was conducted in Kousseri a visceral leishmaniasis (VL) endemic focus with the aim to evaluate the efficiency of light traps and detect Leishmania sp. infection in sand fly specimens. The checklist and distribution map of sand fly species from Cameroon are also provided.

Light traps efficiency was evaluated using incandescent and ultraviolet (UV) Centre for Disease Control and Prevention (CDC) miniature light traps. These traps were deployed across the selected sites in Kousseri, and the captured female specimens were morphologically identified to the species level and tested for Leishmania donovani infection by polymerase chain reaction (PCR) targeting the Internal Transcribed spacer 1 (ITS1) region.

Out of 2150 females collected, eleven species across three genera were identified: 81.44% belonged to the genus Sergentomyia, 17.49% to Grassomyia, and 1.07% to Phlebotomus. UV light traps were more efficient in capturing abundant sand fly specimens than incandescent light traps, specifically, Se antennata, Se schwetzi, Se adleri, and Ph. duboscqi were highly captured. None of the tested sand fly species were positive for Leishmania donovani infection. The present study confirms the existence of Ph. duboscqi, a proven vector of cutaneous leishmaniasis (CL) in sub-Saharan Africa foci, including Cameroon. Based on previous reports of Leishmania transmission, this sand fly species could be the likely vector of leishmaniasis in Kousseri. This study underscores the need for further ecological and epidemiological investigations to deepen our understanding of leishmaniasis transmission dynamics and inform the development of effective control strategies in Northern Cameroon.