Rodents as potential reservoirs for Borrelia spp. in northern Chile / Roedores como potenciais reservatórios de Borrelia spp. no norte do Chile

Abstract Small mammals play an essential role in the transmission and maintenance cycles of Borrelia spirochetes. In Chile, recent studies have characterized novel Borrelia genotypes in ticks collected from small mammals, a fact that suggests these vertebrates are hosts for spirochetes from this genus. Considering this evidence, the goal of this study was to determine the presence of Borrelia DNA in small mammals inhabiting northern Chile. In winter of 2018, 58 small mammals were captured in five localities. Blood samples were collected from rodents and DNA was extracted to determine the presence of Borrelia DNA by PCR targeting the flaB gene and rrs-rrlA intergenic spacer (IGS). From three individuals (5%), belonging to two rodent species of Cricetidae family (Phyllotis xanthopygus and Oligoryzomys longicaudatus), we retrieved three flaB and two IGS Borrelia genotypes. Phylogenetic analyses performed with both Maximum Likelihood and Bayesian inferences showed that our sequences grouped with homologous genotypes from the relapsing fever and Lyme borreliosis groups. Our findings suggest that P. xanthopygus and O. longicaudatus rodents may play a role as reservoirs for borrelial spirochetes in Chile.

Resumo Pequenos mamíferos possuem um papel essencial na transmissão e manutenção de espiroquetas do gênero Borrelia. No Chile, estudos recentes têm descrito novos genótipos de Borrelia em carrapatos, parasitando pequenos mamíferos. Isso sugere que esses vertebrados podem atuar como possíveis reservatórios dessas espiroquetas. Considerando-se essa evidência, o objetivo deste estudo foi determinar a presença de DNA de Borrelia em pequenos mamíferos da região norte do Chile. Durante o inverno de 2018, 58 pequenos mamíferos foram capturados em cinco localidades. Amostras de sangue obtidas a partir dos indivíduos capturados foram submetidas à extração de DNA e ensaios de PCR, para a detecção de Borrelia spp. baseados no gene flaB e espaçador intergênico rrs-rrlA (IGS). A partir de três espécimes (5%) pertencentes a duas espécies de roedores da família Cricetidae (Phyllotis xanthopygus e Oligoryzomys longicaudatus) obtiveram-se três genótipos de Borrelia para o gene flaB e dois para IGS. Análises filogenéticas inferidas, usando-se os métodos Bayesiano e de Máxima Verossimilhança, indicaram que as sequências geradas neste estudo agrupam-se com borrelias do grupo da Febre Recorrente e Borreliose de Lyme. Os achados deste estudo sugerem que roedores P. xanthopygus e O. longicaudatus poderiam atuar como possíveis reservatórios para Borrelia spp. no Chile.

Seroprevalence of Borrelia burgdorferi in occupationally exposed persons in the Belgrade area, Serbia

Lyme disease (LD) is a natural focal zoonotic disease caused by Borrelia burgdorferi, which is mainly transmitted through infected Ixodes ricinus tick bites. The presence and abundance of ticks in various habitats, the infectivity rate, as well as prolonged human exposure to ticks are factors that may affect the infection risk as well as the incidence of LD. In recent years, 20% to 25% of ticks infected with different borrelial species, as well as about 5,300 citizens with LD, have been registered in the Belgrade area. Many of the patients reported tick bites in city’s grassy areas. The aim of this study was to assess the seroprevalence of B. burgdorferi in high-risk groups (forestry workers and soldiers) in the Belgrade area, and to compare the results with healthy blood donors. A two-step algorithm consisting of ELISA and Western blot tests was used in the study. Immunoreactivity profiles were also compared between the groups. The results obtained showed the seroprevalence to be 11.76% in the group of forestry workers, 17.14% in the group of soldiers infected by tick bites and 8.57% in the population of healthy blood donors. The highest IgM reactivity was detected against the OspC protein, while IgG antibodies showed high reactivity against VlsE, p19, p41, OspC, OspA and p17. Further investigations in this field are necessary in humans and animals in order to improve protective and preventive measures against LD.