BMC Malaria Journal (2021) 20 (33) - New assessment of Anopheles

Cécile Nabet, Abdoulaye K. Kone, Abdoulaye K. Dia, Moussa Sylla, Magali Gautier, Mohammed Yattara, Mahamadou A. Thera, Ousmane Faye, Leo Braack, Sylvie Manguin, Abdoul H. Beavogui, Ogobara Doumbo, Frédérick Gay and Renaud Piarroux (2021)
New assessment of Anopheles vector species identification using MALDI-TOF MS
BMC Malaria Journal 20 (33)
Abstract:
Background
Anopheles species identification is essential for an effective malaria vector control programme. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has been developed to identify adult Anopheles species, using the legs or the cephalothorax. The protein repertoire from arthropods can vary according to compartment, but there is no general consensus regarding the anatomic part to be used.
Methods
To determine the body part of the Anopheles mosquitoes best suited for the identification of field specimens, a mass spectral library was generated with head, thorax with wings and legs of Anopheles gambiae, Anopheles arabiensis and Anopheles funestus obtained from reference centres. The MSL was evaluated using two independent panels of 52 and 40 An. gambiae field-collected in Mali and Guinea, respectively. Geographic variability was also tested using the panel from Mali and several databases containing added specimens from Mali and Senegal.
Results
Using the head and a database without specimens from the same field collection, the proportion of interpretable and correct identifications was significantly higher than using the other body parts at a threshold value of 1.7 (p < 0.0001). The thorax of engorged specimens was negatively impacted by the blood meal after frozen storage. The addition of specimens from Mali into the database significantly improved the results of Mali panel (p < 0.0001), which became comparable between head and legs. With higher identification scores, the using of the head will allow to decrease the number of technical replicates of protein extract per specimen, which represents a significant improvement for routine use of MALDI-TOF MS.
Conclusions
The using of the head of Anopheles may improve the performance of MALDI-TOF MS. Region-specific mass spectrum databases will have to be produced. Further research is needed to improve the standardization in order to share online spectral databases.
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Full text of article
Database assignments for author(s): Leo Braack, Sylvie Manguin

Research topic(s) for pests/diseases/weeds:
identification/taxonomy

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Anopheles gambiae		Guinea
	Anopheles gambiae		Mali
	Anopheles arabiensis		South Africa
	Anopheles funestus		Mali