Molecular detection and characterization of Bartonella spp. in rodents from central and southern Chile, with emphasis on introduced rats (Rattus spp.).

Bartonella spp. was screened in 155 rodents from Chile, mainly the invasive rats Rattus norvegicus and Rattus rattus. A total of 155 spleen and 50 blood samples were analyzed through real-time PCR for Bartonella spp. (nuoG gene). Positive samples were subjected to amplification of fragment of loci gltA, rpoB and ITS by conventional PCR (cPCR). Overall, 43 spleen samples (27.7%) and 6 rodent blood samples (12%) were positive for nuoG-Bartonella spp. Positive samples were found in R. norvegicus, R. rattus, Abrothrix olivacea and Oligoryzomys longicaudatus. Bartonella spp. DNA was amplified by cPCR in 16 samples, resulting in 21 sequences (6 gltA, 5 ITS and 10 rpoB). Sequencing and phylogenic analyses identified genotypes from Rattus spp., potentially belonging to Bartonella coopersplainsensis, Bartonella henselae, Bartonella tribocorum, and an undescribed Bartonella sp. From native rodents, one sequence was identified, being related B. machadoae. In conclusion, this work describes diverse and potentially zoonotic Bartonella spp. genotypes in Rattus spp. Additionally, this is the first report of Bartonella in O. longicaudatus, including a potentially novel Bartonella genotype or species.

Cryptosporidium spp. and Giardia spp. in wild rodents: using occupancy models to estimate drivers of occurrence and prevalence in native forest and exotic Pinus radiata plantations from Central Chile.

The conversion of native forest to forestry plantations is a worldwide practice, affecting biodiversity and host-parasite interactions. One of the most common timber plantations in the world are monocultures of Monterey pine (Pinus radiata). Using occupancy models, we analyzed the occurrence and prevalence of Cryptosporidium spp. oocysts and Giardia spp. cysts in fecal samples of wild rodents from a landscape dominated by extensive Monterey pine plantations in central Chile. We aimed to assess drivers of parasite infection such as habitat type, abundance of rodent hosts, species richness, and season. Small mammals were sampled seasonally for two years in three habitat types: native forests, adult pine plantations and young pine plantations. A total of 1091 fecal samples from seven small mammal species were analyzed by coprological analysis. Occurrence probability of Cryptosporidium spp. and Giardia spp. was similar for the most abundant rodent species (Abrothrix longipilis, A. olivacea, and Oligoryzomys longicaudatus) and for all habitat types. For Cryptosporidium spp., variation in prevalence was mostly explained by season with higher prevalence during winter season and lower during spring. For Giardia spp., the prevalence was significantly higher in young pine plantations, followed by adult pine plantations and native forests. In addition, higher prevalence of Giardia spp. was associated with lower host richness, suggesting a possible dilution effect. Our findings reveal that Monterey pine plantations increase Giardia spp. transmission among rodents, but has no clear effect on Cryptosporidium spp., providing evidence that the impact of land use on parasitism can be idiosyncratic. Since both parasites have zoonotic potential, our findings may be useful for land use planning and management considering health issues.

Intestinal Helminths in Wild Rodents from Native Forest and Exotic Pine Plantations (Pinus radiata) in Central Chile.

Native forests have been replaced by forestry plantations worldwide, impacting biodiversity. However, the effect of this anthropogenic land-use change on parasitism is poorly understood. One of the most important land-use change in Chile is the replacement of native forests by Monterey pine (Pinus radiata) plantations. In this study, we analyzed the parasitism (presence and prevalence) of intestinal helminths from fecal samples of wild rodents in three habitat types: native forests and adult and young pine plantations in central Chile. Small mammals were sampled seasonally for two years, and a total of 1091 fecal samples from seven small mammal species were analyzed using coprological analysis. We found several helminth families and genera, some of them potentially zoonotic. In addition, new rodent-parasite associations were reported for the first time. The overall helminth prevalence was 16.95%, and an effect of habitat type on prevalence was not observed. Other factors were more relevant for prevalence such rodent species for Hymenolepis sp. and season for Physaloptera sp. Our findings indicate that pine plantations do not increase helminth prevalence in rodents compared to native forests.