Exposure of Domestic Cats to Distinct Ehrlichia canis TRP Genotypes.

Cats naturally exposed to Ehrlichia canis have been described in different regions of the world, but little is known about the genotypes associated with infection in these animals. To detect E. canis-specific antibodies and investigate the E. canis TRP genotypes in cats, serum samples from 76 domestic cats reactive to crude E. canis antigens by the indirect fluorescence antibody test (IFAT) were analyzed by ELISA, using E. canis-specific peptides (i.e., TRP19 and TRP36 /BR/US/CR). Of these, 25 (32.9%) cats reacted to at least one TRP peptide, confirming their specific exposure to E. canis. Eighteen (23.7%) cats reacted to TRP19, 15 (19.8%) to BRTRP36, and 11 (14.5%) to USTRP36, but none of them reacted to CRTRP36. Eight (10.5%) cats reacted to TRP19 but not to any TRP36 genotype, demonstrating the possible existence of a new E. canis genotype infecting felines. Nevertheless, this study provides the first report of anti-E. canis-specific antibodies in domestic cats.

A new pathogen spillover from domestic to wild animals: Plasmodium juxtanucleare infects free-living passerines in Brazil.

Habitat modification may facilitate the emergence of novel pathogens, and the expansion of agricultural frontiers make domestic animals important sources of pathogen spillover to wild animals. We demonstrate for the first time that Plasmodium juxtanucleare, a widespread parasite from domestic chickens, naturally infects free-living passerines. We sampled 68 wild birds within and at the border of conservation units in central Brazil composed by Cerrado, a highly threatened biome. Seven out of 10 passerines captured in the limits of a protected area with a small farm were infected by P. juxtanucleare as was confirmed by sequencing a fragment of the parasite's cytochrome b. Blood smears from these positive passerines presented trophozoites, meronts and gametocytes compatible with P. juxtanucleare, meaning these birds are competent hosts for this parasite. After these intriguing results, we sampled 30 backyard chickens managed at the area where P. juxtanucleare-infected passerines were captured, revealing one chicken infected by the same parasite lineage. We sequenced the almost complete mitochondrial genome from all positive passerines, revealing that Brazilian and Asian parasites are closely related. P. juxtanucleare can be lethal to non-domestic hosts under captive and rehabilitation conditions, suggesting that this novel spillover may pose a real threat to wild birds.

Molecular detection of tick-borne protozoan parasites in a population of domestic cats in midwestern Brazil.

Some tick-borne pathogens that infect domestic cats have been considered emergent in veterinary medicine. Occurrences of Hepatozoon spp., Babesia spp. and Cytauxzoon spp. have been described in several regions of Brazil. This paper offers a comprehensive analysis of the 18S rRNA gene of a Hepatozoon sp. strain detected in domestic cats in the metropolitan area of Cuiabá, in Midwestern Brazil. Based on a molecular analysis, we detected the presence of Hepatozoon species circulating among cats in this region. The aforementioned strain is closely related to other isolates of H. felis detected in wild felids. Moreover, a phylogenetic analysis indicates that this genotype is grouped into a clade of 18S rRNA sequences previously described for the genus Hepatozoon in wild felids around the world. Hepatozoon felis strains detected in cats from Spain and Israel showed, respectively, 98% and 97% identity to our sequence and are clustered on a separate branch of the phylogenetic tree. This finding suggests a high diversity of Hepatozoon genotypes occurring in cats in Europe and South America. None of the analyzed cats were positive for Babesia spp. or Cytauxzoon spp. by PCR analysis.

Detection of Ehrlichia canis in domestic cats in the central-western region of Brazil.

Ehrlichiosis is a worldwide distributed disease caused by different bacteria of the Ehrlichia genus that are transmitted by arthropod vectors. Its occurrence in dogs is considered endemic in several regions of Brazil. Regarding cats, however, few studies have been done and, consequently, there is not enough data available. In order to detect Ehrlichia spp. in cats from the central-western region of Brazil, blood and serum samples were collected from a regional population of 212 individuals originated from the cities of Cuiabá and Várzea Grande. These animals were tested by the Immunofluorescence Assay (IFA) and the Polymerase Chain Reaction (PCR) designed to amplify a 409 bp fragment of the dsb gene. The results obtained show that 88 (41.5%) cats were seropositive by IFA and 20 (9.4%) cats were positive by PCR. The partial DNA sequence obtained from PCR products yielded twenty samples that were found to match perfectly the Ehrlichia canis sequences deposited on GenBank. The natural transmission of Ehrlichia in cats has not been fully established. Furthermore, tick infestation was not observed in the evaluated cats and was not observed any association between age, gender and positivity of cats in both tests. The present study reports the first serological and molecular detection of E. canis in domestic cats located in the endemic area previously mentioned.