Molecular analysis reveals a high diversity of Anopheles species in Karama, West Sulawesi, Indonesia

Background: Understanding local Anopheles species compositions and bionomic traits are vital for an effective malaria vector intervention strategy. Though eight malaria vectors, including species complexes, have been docu- mented across the island of Sulawesi, Indonesia, a comprehensive survey linking morphological and molecular spe- cies identifcation has not been conducted in this global hotspot of biodiversity.
Results: Eighteen distinct species of Anopheles were molecularly identifed in a 1 km2 area in Karama village, West Mamuju Province, Sulawesi. Known species included An. aconitus, An. karwari, An. peditaeniatus, An. vagus, An. bar- birostris, An. tessellatus, An. nigerrimus, An. crawfordi, An. maculatus, An. favirostris and An. kochi. Of the 18 distinct sequence groups identifed through both ribosomal DNA internal transcribed spacer region 2, and mitochondrial DNA cytochrome c oxidase subunit 1 loci, 8 could not be identifed to species through comparison to published sequences. The comparison of morphological and molecular identities determined that interpretations of local spe- cies compositions for primary and expected species in Karama (An. barbirostris and An. vagus) had the highest rate of accuracy (92.1% and 87.6%, respectively) when compared to molecular analysis. However, the remaining distinct sequences molecularly identifed to species were identifed correctly by morphological methods less frequently, from 0 to 83%.
Conclusions: Karama, Indonesia has a high diversity of Anopheles spp. The unexpected high number of Anopheles species in a small area points to possible complex transmission dynamics and limitations with vector control based on possible varying behaviors and interactions with both humans and interventions. Morphological identifcation of Anopheles spp. in this study was more accurate for primary and expected species than secondary or unexpected spe- cies. Finally, the inability to identify seven sequence groups to species with consensus sequences implies that future studies employing sequencing are required to clarify species compositions in the Nigerrimus Subgroup, amongothers, as well as their distribution and vector status. Use of molecular methods in conjunction with morphological investigations for analysis of species composition, population dynamics and bionomic characteristics is directly implicated in understanding drivers of malaria transmission, intervention efectiveness, and the pursuit of malaria elimination.