Bartonella spp. and Yersinia pestis Reservoirs, Cusco, Peru

To the Editor: Bartonella spp. are gram-negative alphaproteobacte-ria that are transmitted between the reservoir and mammal host by he-matophagous insects (1). The genus Yersinia comprises 11 species, of which Y. pestis is the causative agent of plague, a deadly rodent-associated, fleaborne zoonosis (2). Despite the large number of plague cases reported in humans and the large amount of data about human-infecting Bartonel-la spp. in Peru (3), no data have been published about which rodent species are reservoirs of these pathogens in this country. La Convención Province, where cases of bartonellosis occurred during 1998 (4), is located in the northeastern part of Cusco, Peru. Although, to our knowledge, no human cases of plague have been reported in this province, a plague outbreak was recently detected in Junin Province (M.A. Quispe-Riclade, pers. comm.), which is located northwest of La Con-vención Province. A total of 28 rodents were captured during 2010–2011 in 3 villages (Alto Ivochote, Aguas Calientes, and Yomentoni) in the Echarate District, La Convención Province. Traps had been set in intradomiciliary, peridomi-ciliary, and extradomiciliary settings. Spleens of animals were obtained, and DNA was isolated by using the Illustra Tissue and Cells Genomic Prep Mini Spin Kit (GE Healthcare, Little Chal-font, UK). Rodents were examined for Bar-tonella spp. DNA by using a PCR and primers CS443f and CS1210r specific for a 767-bp fragment of the citrate synthase gene (5). Screening for plague was performed by using PCR primers Yp1 and Yp2 specific for a plasminogen activator protein (pla) encoded by the Y. pestis–specific pPLA plasmid (6). New and published Bartonella spp. and Y. pestis sequences were obtained from GenBank and compared by using the nucleotide-nucleotide basic local sequence alignment tool (BLAST) (blastn) program (www. 2 test was used to determine statistical differences in the prevalence of both pathogens among host species and villages. Overall prevalences for Y. pes-tis and Bartonella spp. were 17.9% and 21.4%, respectively (Table). Co-infections with both bacteria were found in 3 (10.7%) rodents: 2 Hylaeamys perenensis rodents and 1 Oecomys spp. rodent. Bartonella prevalence was higher in H. perenen-sis rats than in Rattus rattus rodents (p<0.001). Rodents positive for Bar-tonella spp. were found in the 3 study villages, and prevalence for Aguas Calientes was higher than that for Alto Ivochote (p<0.001). One of 8 rodents trapped inside houses and 1 of 2 rodents trapped at peridomestic sites were positive for Bartonella spp. Sequence analysis identified 3 citrate synthase …