Borrelia burgdorferi sensu lato infecting Ixodes auritulus ticks in Uruguay.

In the southern cone of South America different haplotypes of Borrelia burgdorferi sensu lato (Bbsl) have been detected in Ixodes spp. from Argentina, southern Brazil, Chile, and Uruguay. So far, Lyme borreliosis has not been diagnosed in Uruguay and the medical relevance of the genus Ixodes in South America is uncertain. However, the growing number of new genospecies of Bbsl in the southern cone region and the scarce information about its pathogenicity, reservoirs and vectors, highlights the importance of further studies about spirochetes present in Uruguay and the region. The aim of this study was to determine the presence of Bbsl in Ixodes auritulus ticks collected from birds and vegetation in two localities of southeastern Uruguay. In total 306 I. auritulus were collected from 392 passerine birds sampled and 1110 ticks were collected by flagging in vegetation. Nymphs and females were analyzed for Borrelia spp. by PCR targeting the flagellin (fla) gene and the rrfA-rrlB intergenic spacer region (IGS). The phylogenetic analysis of Borrelia spp. positive samples from passerine birds and vegetation revealed the presence of four fla haplotypes that form a clade within the Bbsl complex. They were closely related to isolates of Borrelia sp. detected in I. auritulus from Argentina and Canada.

Borrelia infection in Ixodes pararicinus ticks (Acari: Ixodidae) from northwestern Argentina.

The aim of this work was to describe for the first time the presence of Borrelia burgdorferi sensu lato infecting ticks in Argentina. Unfed specimens of Ixodes pararicinus collected from vegetation in Jujuy Province were tested for Borrelia infection by PCR targeting the gene flagellin (fla), the rrfA-rrlB intergenic spacer region (IGS) and the 16S rDNA (rrs) gene. One male and one female of I. pararicinus collected in Jujuy were found to be positive to Borrelia infection with the three molecular markers tested. Phylogenetically, the Borrelia found in I. pararicinus from Jujuy belongs to the B. burgdorferi s.l complex, and it was similar to one of the genospecies detected in I. aragaoi from Uruguay. Also, this genospecies is closely related to two genospecies known from USA, Borrelia americana and the Borrelia sp. genospecies 1. The epidemiological risk that implies the infection with Borrelia in I. paracinus ticks from Argentina appears to be low because the genospecies detected is not suspected of having clinical relevance and there are no records of Ixodes ticks biting humans in the southern cone of South America. Further studies are needed to assess accurately if there is risk of borreliosis transmitted by ticks in South America.

Borrelia burgdorferi sensu lato infecting ticks of the Ixodes ricinus complex in Uruguay: first report for the Southern Hemisphere.

The Borrelia burgdorferi sensu lato (s.l.) group comprises genetically related spirochetes, mostly associated with tick species belonging to the Ixodes ricinus complex in the Northern Hemisphere. The present study evaluated borrelial infection in the tick Ixodes pararicinus, which is the only representative species of the I. ricinus complex in Uruguay. A total of 137 I. pararicinus ticks were collected from deer, cattle, or vegetation in 2 Uruguayan Departments. A part of these ticks was tested directly by PCR targeting the borrelial gene flagellin (fla), whereas another part of the ticks was inoculated into Barbour-Stoenner-Kelly (BSK)-H medium in an attempt to isolate Borrelia. Overall, Borrelia infection was detected in 9 males and 1 nymphal tick pool. These ticks were found to be infected by unique fla haplotypes, which were shown through phylogenetic analysis to represent possibly 2 new B. burgdorferi s.l. genospecies, 1 associated with B. bissettii, the other phylogenetically closest to B. americana. These results were reinforced by PCR and DNA sequencing analyses of portions of 2 additional borrelial genes, rrfA-rrlB intergenic spacer region (IGS) and 16S rDNA (rrs). Weekly examinations of BSK cultures by dark-field microscopy failed to demonstrate live Borrelia through a 100-day incubation period. However, Borrelia DNA was detected by fla-PCR in culture media from 2 vials up to 90 days after inoculation. To the best of our knowledge, this is the first report of B. burgdorferi s.l. infecting ticks in South America.

First report of the isolation and molecular characterization of Rickettsia amblyommii and Rickettsia felis in Central America.

During 2010, 15 adult ticks, identified as Amblyomma cajennense, were collected from horses in Cahuita and Turrialba districts, whereas 7 fleas, identified as Ctenocephalides felis, were collected from a dog in San Jose city, Costa Rica. In the laboratory, three A. cajennense specimens, two from Cahuita and one from Turrialba, were individually processed for rickettsial isolation in cell culture, as was a pool of seven fleas. Rickettsiae were successfully isolated and established in Vero cell culture from the three ticks and from a pool of seven fleas in C6/36 cell culture. The three tick isolates were genotypically identified as Rickettsia amblyommii, and the flea isolate was identified as Rickettsia felis through DNA sequencing of portions of the rickettsial genes gltA, ompA, and ompB of each isolate. In addition, other seven ticks were shown to contain rickettsial DNA. Polymerase chain reaction products of at least two of these ticks were sequenced and also showed to correspond to R. amblyommii. Overall, 66.7% (10/15) of the A. cajennense adult ticks were found to be infected with rickettsiae. This is the first report of a successful isolation in cell culture of R. amblyommii and R. felis from Central America.