Natural Plasmodium infection of Anopheles benarrochi B (Diptera: Culicidae) in native communities of the Province of Condorcanqui, Amazonas-Peru

Abstract

Abstract Background Malaria is a severe health problem in the native communities of Condorcanqui in the Amazonas Department of Peru. Recently, the number of malaria cases has increased considerably following a Plasmodium falciparum outbreak in 2019. However, there is no information on the anopheline species acting as Plasmodium vectors in this area or its insecticide resistance status. This study aims to: i) to molecularly characterize the anopheline population from the district of Rio Santiago; ii) to determine their incrimination in malaria transmission; and iii) to evaluate mutations associated with resistance to pyrethroid insecticides and DDT in the mosquito population. Methods Mosquitoes were collected between March and September 2022, using Shannon traps, CDC light traps, and mouth aspirators. Only those morphologically identified as Anopheles sp. were subjected to molecular confirmation by PCR amplification and sequencing of the COX1 barcode region. Additionally, specimens that were molecularly confirmed as Anopheles were analyzed for the kdr region of the VGSC gene related to insecticide resistance. Likewise, the presence of human blood as a food source was detected using the β-globin marker, and the presence of P. falciparum and Plasmodium vivax was determined through a nested PCR. Results A total of 453 mosquitoes were captured, of which ninety-four were morphologically identified as female anophelines. Of the latter, sixty-six (~ 70%) specimens were molecularly confirmed as anophelines and were grouped into four species: An. benarrochi B, An. triannulatus, An. costai and An. nimbus. The sixty-six anophelines were analyzed for human β-globin and Plasmodium. It was found that twenty-three samples of An. benarrochi B (~ 35%) and one specimen of An. triannulatus were positive for human β-globin. Likewise, six (~ 9%) samples of An. benarrochi B were positive for Plasmodium parasites (four for P. falciparum and two for P. vivax). It is worth noting that four specimens tested positive for Plasmodium parasites and human blood simultaneously, making this a robust outcome to incriminate An. benarrochi B as the main malaria vector. No specimens presented mutations associated with insecticide resistance in the kdr region. Conclusions An. benarrochi B is the dominant anopheline species in this study and plays an important role in malaria transmission. Further studies are needed to understand its feeding behavior and activity during dry and rainy seasons to fully incriminate it with malaria transmission and implement targeted vector control programs.