Resumo Este estudo teve como objetivo investigar a diversidade genética de Hepatozoon spp. em roedores de Valdivia, Chile. Um total de 74 roedores (sinantrópicos n=38; selvagens n=36) foram capturados. PCR convencional foi realizada para organismos Apicomplexa, visando dois fragmentos sobrepostos do gene 18S rDNA (600 bp e 900 bp), seguida pelo sequenciamento de amplicons selecionados. A ocorrência de Hepatozoon spp. foi de 82,43% (61/74). Doze sequências obtidas dos fragmentos de 18S rDNA de 600 pb e dez dos fragmentos de 18S rDNA de 900 pb foram identificadas como Hepatozoon sp. Seis sequências obtidas, a partir de protocolos de PCR sobrepostos, foram usadas para análises filogenéticas (1.400 bp), de haplótipos e de distância. Sequências concatenadas 18S rDNA do presente estudo foram detectadas em Oligoryzomys longicaudatus, Rattus norvegicus, Mus musculus e Abrothrix longipilis e agrupadas com Hepatozoon descrito em roedores e répteis do Chile e do Brasil. A análise de polimorfismos das seis sequências deste estudo, junto com outras sequências chilenas de roedores e carrapatos de roedores, mostrou alta diversidade com um total de nove haplótipos no Chile. Três haplótipos detectados em Valdivia foram identificados pela primeira vez neste estudo, sugerindo que novos haplótipos circulam em roedores do sul do Chile.

Abstract This study aimed to investigate the genetic diversity of Hepatozoon spp. in rodents from Valdivia, Chile. A total of 74 rodents (synanthropic n=38; wild n=36) were trapped in Valdivia. We performed conventional PCR assays for Apicomplexa organisms targeting two overlapping 18S rDNA gene fragments (600 bp and 900 bp) followed by sequencing of selected amplicons. Hepatozoon spp. occurrence was 82.43% (61/74). Twelve sequences obtained from the 600 bp and ten from the 900 bp 18S rDNA fragments were identified as Hepatozoon sp. Six sequences obtained from 18S rDNA-based overlapping PCR protocols were used for concatenated (1,400 bp) phylogenetic, haplotype and distance analyses. Hepatozoon spp. 18S rDNA concatenated sequences from the present study were detected in Oligoryzomys longicaudatus, Rattus norvegicus, Mus musculus, and Abrothrix longipilis grouped with Hepatozoon species earlier described in rodents and reptiles from Chile and Brazil. Nucleotide polymorphism of the six 18S rDNA sequences (1,400 bp) from this study, and other Chilean sequences from rodents and rodent’s ticks, showed high diversity with a total of nine Chilean haplotypes. Three haplotypes from Valdivia were identified for the first time in this study, suggesting the circulation of novel haplotypes in rodents from southern Chile.

ABSTRACT: The aim of the present study was to assess the performance of routinely used diagnostic tests to detect M. bovis infection in cattle populations with very low infection prevalence. A cross-sectional study was performed using 609 animals from 17 herds that were sampled for blood interferon, and tested with the caudal fold tuberculin test (CFT). It was planned that animals which showed CFT positive results were sent to the slaughterhouse for post mortem confirmation testing. However, not all the animals considered in the initial sampling were culled. Paired population proportions of positive results for the different diagnostic tools were compared. Apparent sensitivity and specificity was also estimated. Overall, intradermal tuberculin based diagnostics showed better performance in comparison to interferon based test, even though interferon was slightly more specific. From these results, it may be suggested that specific cut-off lines for interferon based techniques for certain areas with particular low bTB prevalence should be considered, as well as the modification of more specific antigens and the use of better combinations of PPDs if in vitro testing is intended must be taken into consideration. The uncertain role of interference bacteria that could be affecting the results of the in vitro analysis must be considered, and perhaps this could explain the apparent lack of consensus of the results obtained in Chile versus the ones obtained elsewhere. More studies must be performed in order to assess this issue.

ABSTRACT: A cross-sectional study using 99 serum samples of dogs from southern Chile was conducted to determine the diagnostic utility of a rapid immunochromatography assay for the detection of Leptospira specific IgM antibodies as screening test and as a potential aid in the diagnosis of leptospirosis in animals with and without clinical suspicion of the disease. The Microscopic Agglutination Test (MAT) was used as reference assay. Anti-Leptospira antibodies were detected in 37.3% of the dogs with MAT. Using the immunochromatography test, specific IgM antibodies were found in 13.1% of sampled dogs. The sensitivity of the rapid test as screening assay was 29.7% (95% Confidence Interval=16.4-47.2) and the specificity was 96.7% (95% Confidence Interval=87.8-99.4). 40.0% of the canines with clinical suspicion of leptospirosis and 37.1% of dogs without clinical signs were serological reactors to MAT, but none of MAT reactive dogs with clinical suspicion tested positive in the rapid test. Rapid and user-friendly diagnostic procedures for canine leptospirosis such as this immunochromatography assay could be important tools to use in clinical practice, however, further studies are needed to obtain more information about their utility, considering that diagnostic tests could not have similar performances in different geographic locations, clinical and epidemiological contexts.