MALDI-TOF MS as an innovative tool for detection of Plasmodium parasites in Anopheles mosquitoes

Background: Malaria is still a major public health issue worldwide, and ă one of the best approaches to fight the disease remains vector control. ă The current methods for mosquito identification include morphological ă methods that are generally time-consuming and require expertise, and ă molecular methods that require laboratory facilities with relatively ă expensive running costs. Matrix-Assisted Laser Desorption Ionization ă Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) technology, routinely ă used for bacterial identification, has recently emerged in the field of ă entomology. The aim of the present study was to assess whether MALDI-TOF ă MS could successfully distinguish Anopheles stephensi mosquitoes ă according to their Plasmodium infection status. ă Methods: C57BL/6 mice experimentally infected with Plasmodium berghei ă were exposed to An. stephensi bites. For the determination of An. ă stephensi infection status, mosquito cephalothoraxes were dissected and ă submitted to mass spectrometry analyses and DNA amplification for ă molecular analysis. Spectra were grouped according to mosquitoes' ă infection status and spectra quality was validated based on intensity ă and reproducibility within each group. The in-lab MALDI-TOF MS arthropod ă reference spectra database, upgraded with representative spectra from ă both groups (infected/non-infected), was subsequently queried blindly ă with cephalothorax spectra from specimens of both groups. ă Results: The MALDI TOF MS profiles generated from protein extracts ă prepared from the cephalothorax of An. stephensi allowed distinction ă between infected and uninfected mosquitoes. Correct classification was ă obtained in blind test analysis for (79/80) 98.75% of all mosquitoes ă tested. Only one of 80 specimens, an infected mosquito, was ă misclassified in the blind test analysis. ă Conclusions: Matrix-Assisted Laser Desorption Ionization Time-Of-Flight ă Mass Spectrometry appears to be a promising, rapid and reliable tool for ă the epidemiological surveillance of Anopheles vectors, including their ă identification and their infection status.