Using MALDI-TOF MS to Identify Mosquitoes from Senegal and the Origin of Their Blood Meals.

Simple Summary: Mosquitoes are capable of transmitting numerous diseases to humans and animals. However, not all mosquitoes are vectors. It is therefore very important to identify mosquitoes in order to distinguish vectors from non-vectors. Our aim was to evaluate the ability of MALDI-TOF MS to identify mosquitoes collected in Senegal and stored for several months in silica gel, and to determine the origin of their blood meal. We have identified 12 different species, most of which are vectors of human disease. We also found that these mosquitoes fed mainly on humans. Our results confirm that MALDI-TOF MS is a promising and rapid technique for identifying mosquitoes and the origin of their blood meal. However, the percentage of good-quality spectra was low, demonstrating that mosquitoes should be pre-treated before being preserved in silica gel. Transferring the MALDI-TOF MS database to Senegal will enable mosquitoes to be identified on the spot as quickly as possible. Mosquitoes are arthropods that represent a real public health problem in Africa. Morphology and molecular biology techniques are usually used to identify different mosquito species. In recent years, an innovative tool, matrix-assisted desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), has been used to identify many arthropods quickly and at low cost, where equipment is available. We evaluated the ability of MALDI-TOF MS to identify mosquitoes collected in Senegal and stored for several months in silica gel, and to determine the origin of their blood meal. A total of 582 mosquitoes were collected and analysed. We obtained 329/582 (56.52%) MALDI-TOF MS good-quality spectra from mosquito legs and 123/157 (78.34%) good-quality spectra from engorged abdomens. We updated our home-made MALDI-TOF MS arthropod spectra database by adding 23 spectra of five mosquito species from Senegal that had been identified morphologically and molecularly. These included legs from Anopheles gambiae, Anopheles arabiensis, Anopheles cf. rivulorum, Culex nebulosus, Anopheles funestus, and three spectra from abdomens engorged with human blood. Having updated the database, all mosquitoes tested by MALDI-TOF MS were identified with scores greater than or equal to 1.7 as An. gambiae (n = 64), Anopheles coluzzii (n = 12), An. arabiensis (n = 1), An. funestus (n = 7), An. cf rivulorum (n = 1), Lutzia tigripes (n = 3), Cx. nebulosus (n = 211), Culex quinquefasciatus (n = 2), Culex duttoni (n = 1), Culex perfescus (n = 1), Culex tritaeniorhynchus (n = 1), and Aedes aegypti (n = 2). Blood meal identification by MALDI-TOF MS revealed that mosquitoes had fed on the blood of humans (n = 97), cows (n = 6), dogs (n = 2), goats (n = 1), sheep (n = 1), and bats (n = 1). Mixed meals were also detected. These results confirm that MALDI-TOF MS is a promising technique for identifying mosquitoes and the origin of their blood meal. [ABSTRACT FROM AUTHOR]