Maria Isabel Botelho Vieira

Rangelia vitalii, Babesia spp. and Ehrlichia spp. in dogs in Passo Fundo, state of Rio Grande do Sul, Brazil

Pathogens transmitted by ticks are an emerging problem worldwide, this study aimed to diagnose the causal agents of infection in dogs presenting suspected hemoparasitoses. Fifty-eight dogs with clinical signs such as depression, hemorrhagic diathesis and fever were evaluated regarding clinical presentation, hemogram, blood smears and serological tests, using the indirect immunofluorescence method for the agents Babesia vogeli and Ehrlichia canis and conventional PCR for Babesia spp. (gene 18S rRNA), Rangelia vitalii (gene 18S rRNA) and Ehrlichia spp. (gene dsb). Five (8.6%) of the 58 dogs were serologically positive for Babesia spp. and three (5.1%) for E. canis. Four dogs (6.8%) were positive for R. vitalii through the molecular diagnosis. The PCR products were sequenced and the DNA from R. vitalii was found to be 99% genetically identical to samples of R. vitalii that had been isolated in Brazil. No presence of Babesia spp. or E. canis was observed through PCR on the dogs evaluated here. The results indicate the presence of R. vitalii and exposure to Babesia spp. and Ehrlichia spp. among the dogs analyzed.Pathogens transmitted by ticks are an emerging problem worldwide, this study aimed to diagnose the causal agents of infection in dogs presenting suspected hemoparasitoses. Fifty-eight dogs with clinical signs such as depression, hemorrhagic diathesis and fever were evaluated regarding clinical presentation, hemogram, blood smears and serological tests, using the indirect immunofluorescence method for the agents Babesia vogeli and Ehrlichia canis and conventional PCR for Babesia spp. (gene 18S rRNA), Rangelia vitalii (gene 18S rRNA) and Ehrlichia spp. (gene dsb). Five (8.6%) of the 58 dogs were serologically positive for Babesia spp. and three (5.1%) for E. canis. Four dogs (6.8%) were positive for R. vitalii through the molecular diagnosis. The PCR products were sequenced and the DNA from R. vitalii was found to be 99% genetically identical to samples of R. vitalii that had been isolated in Brazil. No presence of Babesia spp. or E. canis was observed through PCR on the dogs evaluated here. The results indicate the presence of R. vitalii and exposure to Babesia spp. and Ehrlichia spp. among the dogs analyzed.

Serological detection and molecular characterization of piroplasmids in equids in Brazil

Equine piroplasmosis is a disease caused by the hemoparasites Babesia caballi and Theileria equi and is considered to be the most important parasitic infection affecting Equidae. The objective of the present study was to carry out an epidemiological molecular and serological survey for the presence of these two protozoal organisms in equids from the northwestern region of the State of Rio Grande do Sul (RS), south Brazil. For this purpose, blood samples were collected from 90 equids in the city of Passo Fundo, RS, Brazil. Those were animals used for sport activities, outdoor recreational riding, and work including cattle herding and mounted patrol. Anti-T. equi and anti-B. caballi IgG antibodies were detected in the sera of those animals by commercial ELISA kits. The molecular diagnosis of equine piroplasmosis due to T. equi or B. caballi (or both) consisted in the amplification of the 18S rRNA gene by nested PCR followed by sequencing of the amplified PCR product and sequence comparison and phylogenetic analysis of the isolates; 17 (18.9%) and 5 (5.55%) out of the 90 serum samples tested in this study were positive for T. equi and B. caballi, respectively. Piroplasmid 18S rRNA gene fragments were detected by PCR in 24.4% (22/90) of the samples analysed and shared 99-100% identity with sequences of T. equi by BLASTn. Samples for the phylogenetic analysis were divided into 2 groups. In group A, there was close phylogenetic relationship between 4 sequences and sequences previously reported along the US-Mexico border, in South Africa, and in Brazil. There was a phylogenetic proximity between 5 samples from group B and samples tested by other authors in the US and Spain. Variation of the 18S rRNA gene allowed the identification of 9 new T. equi genotypes in the geographical region studied.

Role of Immunohistochemistry in the Diagnosis of Leptospirosis in Neotropical Primates

Background: Leptospirosis is considered the most widespread zoonosis worldwide, occurring more frequently in tropical and developing regions. The aim of the present study was to detect the presence of Leptospira spp. in different primate tissues, using immunohistochemical (IHC) assays, taking advantage of the considerable number of necropsies compatible with a diagnosis of leptospirosis in neotropical primates at the Animal Pathology Laboratory (APL) of the University of Passo Fundo (UPF) in the northern region of Rio Grande do Sul. Materials, Methods & Results: Paraffin-embedded primate tissue samples were selected from necropsy examinations and subjected to IHC. The streptavidin-biotin-peroxidase method was used with diaminobenzidine chromogen (DAB) to verify immunostaining. Of the101 primates tested for Leptospira spp., 51.48% were positive; taining was distributed between lung (76.92%), liver (44.23%), and kidney (32.69%) tissue. Analysis of the combined anatomopathological verification data of the studied organs revealed a high frequency of lesions commonly observed in the tissues of animals exposed to the pathogen. For complementary diagnosis, an anti-Leptospira spp. antibody test was performed in primates at the UPF-Zoo, from which a population of the necropsied animals originated. The microscopic agglutination test (MAT) was utilized, which demonstrated 90.47% positivity in 21 individuals; sejroe and panama were the most frequent serovars. Discussion: Different intensities of tissue immunostaining were observed. Areas of fragmented or diffuse staining were considered to indicate equal positivity to that indicated by areas of staining with preserved morphology. Of 52 Leptospirapositive primates, most presented some degree of staining in lung samples, which shows a high level of involvement for this organ in primate leptospirosis. Conventional pathological diagnostic methods do not allow fort issue antigen recognition, thus making the IHC technique important to facilitate conclusive antigen sample verification. In the liver, leptospires were detected mostly between the sinusoids, hepatocytes, and Kupffer cells. In kidney tissues, staining indicated small agglomerates in the tubular lumen, interstitium, and glomeruli. All these forms of presentation have been previously reported. Considering that we detected the highest number of positive samples in lung tissue, followed by those from liver and kidney tissue, we argue that the IHC technique, when applied to samples of these three tissues, decreases the chance of false negatives. Anatomopathological studies of primate leptospirosis are scarce. In dogs, renal lesions are characterized by the necrosis and degeneration of tubular epithelium, cellular debris, and hyaline cylinders. In the liver, hepatocyte cord dissociation and biliary pigment accumulation within the canaliculi and hepatocellular necrosis are observed. These findings are similar to those from our study. In the lung, diffuse alveolar lesions are reported, with hemorrhage and edema, in addition to capillaritis. The high frequency of Leptospira-positive animals determined by serological examination was consistent with the IHC findings, thus confirming the pathogen’s high prevalence in neotropical primate populations in the studied region. Serological surveys on primate populations have already been carried out and have revealed frequency and serovar variations between regions. Immunohistochemical examination allows the detection of leptospires in various tissues and should be used based on the characteristics of the investigated case.

Re-emergence of Chorioptes bovis (Acari: Psoroptidae) in cattle in the state of Rio Grande do Sul, Brazil

Here we describe an outbreak of chorioptic mange in cattle, 56 years after its first identification in Brazil. Between the months of June and July 2011, dermatitis characterized by alopecia and crusted and thickened skin at the insertion of the tail and in the ischiorectal fossa was recognized in 40 (35.7%) out of 112 Holstein cows on a farm in the northeastern mesoregion of the state of Rio Grande do Sul, Brazil. After diagnosing mange caused by Chorioptes bovis, the cows were weighed and treated with 0.5% ivermectin, as a pour-on single dose, and were separated into two groups: cows in early lactation and those in late lactation. The survival rate of C. bovis and the healing rate in the two groups of infested cows were monitored every seven days through skin scrapings. After 28 days of evaluation, the cure rate through treatment was greater among cows in early lactation (p <0.0001). The survival rate of C. bovis was higher in cows in late lactation.