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

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.