Rickettsia detection in fleas associated with cricetid rodents in a periurban area of Argentina

Abstract

This study analysed the presence of Rickettsia (Rickettsiales: Rickettsiaceae) in fleas(Siphonaptera) associated with cricetid rodents in periurban localities of Gran La Plata,Argentina. Rodents were captured in three localities and fleas were collected directlyfrom their fur. After DNA extraction, fleas were prepared for microscopic identification.PCR amplification of gltA and ompB genes was performed on each individual flea todetect and identify Rickettsia. The OmpB gene was sequenced and compared usingnBLAST to initially identify its similarity with other sequences from GenBank. A phyloge-netic tree was constructed to evaluate the relationships of the sequences obtained withothers deposited in GenBank. Out of the 253 cricetids (seven species) captured, 87 fleas(four species) were collected. Of them, 10 fleas (11.5%) tested positive for Rickettsia.According to nBLAST and the phylogenetic tree results, sequences of this study wereidentified as R. felis Bouyer et al. Those sequences were obtained only from five of theseven cricetid species and from two of the three localities, as follows: from Street143 and Diagonal 630, Arana neighbourhood, La Plata District: Polygenis (Polygenis) axius(Jordan and Rothschild) (n = 3) and Polygenis (Neopolygenis) atopus (Jordan and Roth-schild) (n = 1); and from Balneario La Balandra, Berisso District: Polygenis (Polygenis) axius(n = 4), Polygenis (Neopolygenis) atopus (n = 1) and Craneopsylla minerva minerva(Rothschild) (n = 1). Our results confirm the presence of R. felis in fleas parasitizing crice-tids in the periurban area of Gran La Plata, which could represent a risk to public health.