Accurate identification of Anopheles gambiae Giles trophic preferences by MALDI-TOF MS

The determination of the trophic preferences of the Anopheles gambiae Giles (Diptera: Culicidae) is a decisive parameter for the monitoring and the prevention of malaria risk transmission. Currently, arthropod blood feeding sources are identified using immunological or molecular biology traditional techniques. Despite the effectiveness of these methods, they present several limitations, and notably, they are time-consuming and costly techniques. A recent study demonstrated that MALDI-TOF MS could be a useful tool for the identification of blood meal origins in freshly engorged mosquitoes. However, the limited number of blood vertebrate species tested to date, did not allow an assessment of the efficiency of MALDI-TOF MS in distinguishing blood MS spectra among close host species, such as humans versus primates. Therefore, in the present study, blood from ten distinct vertebrate host species, including four domestic species, four wild species, and two primates, was selected to control the reliability of MALDI-TOF MS based identification. Host blood species-specific MS profiles, up to 24h post-feeding in engorged Anopheles abdomens, were confirmed. Blind tests underlined the high specificity of MS spectra for the recognition of each host species, preventing misidentification. Nevertheless, an accurate analysis of the results from MS spectra queried against the MS database revealed that the reliability of identification is directly linked to the comprehensiveness of the MS reference database. Finally, the rapidity, the low-cost reagents, the simplicity of data analysis, and the accuracy of the tool for blood origin determination, make this proteomic strategy a promising complementary method for the elucidation of host/vector interactions.