Rickettsia in fleas of rodents from Arana (ARA), La Balandra (BLB) and Estación Experimental Julio Hirschhörn (EEJH) between 2017–2019

Abstract

This study analyzed 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 directly from their fur. After DNA extraction, fleas were prepared for microscopic identification. PCR amplification of gltA and ompB genes were performed on each individual flea to detect and identify Rickettsia. OmpB gene was sequenced and compared using nBLAST to initially identify their similarity with other sequences from Genbank. A phylogenetic tree was constructed to evaluate the relationships of the sequences obtained with others deposited in GenBank. Out of the 253 cricetids (seven species) captured, 87 fleas (four species) were collected. Of them, ten fleas (11.5%) tested positive for Rickettsia. According to nBLAST and the phylogenetic tree results, sequences of this study were identified as R. felis (Bouyer et al. 2001). Those sequences were obtained only from five of the seven cricetid species and from two of the three localities, as follows: from Street 143 and Diagonal 630, Arana Neighborhood, La Plata District: Polygenis (Polygenis) axius axius (Jordan & Rothschild, 1926) (n=3) and Polygenis (Neopolygenis) atopus (Jordan & Rhotschild, 1922) (n=1); and from Balneario La Balandra, Berisso District: Polygenis (Polygenis) axius axius (n=4), Polygenis (Neopolygenis) atopus (n=1), and Craneopsylla minerva minerva (Rothschild, 1903) (n=1). Our results confirm the presence of R. felis in fleas parasitizing cricetids in the periurban area of Gran La Plata, which could represent a risk in public health.