Investigating the potential sibling species status of Anopheles fluviatilis in Gadchiroli (Maharastra).

Background objectives: India has made significant progress in combating malaria and reducing malaria-related mortality and morbidity. Yet, local transmission and malaria hotspots are important hurdles as India looks to achieve malaria elimination by 2030. Gadchiroli district is a highly malaria-endemic area in Maharashtra, India. It accounts for more than 50% of the reported malaria cases in the state. An. culicifacies and Anopheles fluviatilis are the primary malaria vector in the area. However, the status of vector sibling species is unknown in the district In this study, we aimed to identify the sibling species of Anopheles fluviatilis present in the district.

Methods: An. fluviatilis were collected from the human dwelling of the Dhanora block of the Gadchiroli district. The anopheline mosquitoes were identified morphologically and dissected for detachment of the head and thorax. Sibling species, Incrimination investigations, and analyses of blood meal sources were conducted using polymerase chain reaction (PCR).

Results: Two sibling species of An. fluviatilis S and U were present in the study area. Sibling species S was more prevalent than sibling species U. An. fluviatilis S was found to ingest human blood meal. An. fluviatilis U was feeding on cattle. Nevertheless, none of the samples were found positive for sporozoites or oocysts.

Interpretation conclusion: The propensity for malaria transmission varies across sibling species of An. fluviatilis. An. fluviatilis sibling-species S is more prevalent in the Gadchiroli district than sibling species U. The sibling species S was reported to play a major role in malaria transmission in central India. An. fluvilitilis S feeds on humans and sibling species U was found to be more zoophilic. The resting behaviour of both the species was in human dwelling, and it can enhance interaction with the sprayed walls. Consequently, to achieve the objective of malaria elimination, it is imperative to conduct a study of vector bionomics at the sibling species level to designate the most suitable vector control tools.