Molecular evidence of Bartonella spp. in biting midges of the genus Culicoides Latreille (Diptera: Ceratopogonidae) from Brazil

Abstract

Bartonella spp. are typical vector-borne pathogens, whose transmission has been primarily associated with a wide variety of hematophagous arthropods. These bacteria are responsible for several clinical syndromes in both humans and animals. The present study aimed to investigate the occurrence and molecular identity of Bartonella spp. in 345 specimens of Culicoides Latreille from the Brazilian Amazon. Out of 345 Culicoides specimens collected in the Amazon National Park, state of Pará, northern Brazil, 86.7 % (299/345) were positive for the endogenous cytochrome c oxidase subunit 1 gene. We detected a 24 % (72/299) prevalence rate for Bartonella spp. using a quantitative real-time PCR targeting the 16S-23S rRNA internal transcribed spacer (ITS) region. Culicoides foxi was statistically more associated with Bartonella positivity when compared to C. hylas and C. leopoldoi. Culicoides specimens collected at the ground level were more associated with positivity for Bartonella spp. when compared to those collected at the canopy. Further molecular characterization was performed using conventional PCR assays targeting seven molecular markers (nuoG, gltA, groEL, ftsZ, rpoB, pap31, and ribC). The BLASTn analysis revealed four gltA sequences with 99.72-100 % identity to Bartonella bovis previously detected in cattle from Brazil. One ribC sequence showed 100 % identity to Bartonella henselae previously detected in a cat from Germany. Six pap31 sequences showed 90-91 % identity to a Bartonella sp. sequence previously detected in a bat (Carollia perspicillata) from Brazil. This study represents the first molecular evidence of Bartonella spp. DNA in biting midges and contributes to understanding their role in the epidemiological cycles of these agents.