A total of 382 stool samples were examined during a survey of intestinal parasites in members of the Tapirapé ethnic group, who live in the Brazilian Amazon region of Mato Grosso. Fecal DNAs from Blastocystis-positive samples were extracted, polymerase chain reaction amplified using Blastocystis-specific primers targeting the small subunit rRNA gene, and sequenced. Three subtypes (STs) were identified: ST1 (41%), ST2 (32%), and ST3 (17%). Seven mixed infections were found (11%). The subtype distribution was markedly different from that reported in Europe in that ST4 was not detected and ST3 was not the most common subtype. This study is the first to include molecular characterization of Blastocystis in Brazil and in indigenous communities from Latin America.

Background: Blastocystis sp. affects a wide variety of animals and is the most common protozoan in human fecal samples with potential pandemic distribution. In the present study, a systematic review and meta-analysis were conducted to determine the prevalence and distribution of Blastocystis sp. in different classes of hosts in Brazil. Methods: Studies that analyzed hosts of various classes, including humans, domestic animals, wild animals or captive animals, were considered. The pooled prevalence of Blastocystis sp. infection was estimated by random effects models. Results: For humans, similar prevalence rates were found for males (31.0%, 95% CI: 17.0-45.0%; weight 10%) and females (28.0%, 95% CI: 16.0-41.0%; weight 10%); the state of Mato Grosso do Sul showed the highest prevalence, with 41.0% positivity (95% CI: 36.0-46.0%; weight 2.9%). The prevalence among immunocompromised patients was 5.0% (95% CI: 3.0-7.0%; weight 10%), and the most common cause of immunosuppression was hemodialysis, with 23.0% (95% CI: 17.0-29.0%; weight 12.4%). Among classifications according to interaction with humans, wild and domestic animals presented values of 19.0% (95% CI: 7.0-31.0%; weight 42.6%) and 17.0% (95% CI: 13.0-21.0%; weight 29.6%), respectively. Among these animals, mammals (39.0%, 95% CI: 21.0-56.0%; weight 47.3%) and birds (18.0%, 95% CI: 10.0-27.0%; weight 39.3%) exhibited the highest prevalence. Phylogenetic analysis of Blastocystis sp. revealed greater genetic diversity for clades of subtypes (STs) ST1, ST2 and ST3. Conclusions: The overall prevalence of Blastocystis sp. in the Brazilian human population was 24%, which reflects the reality in the South, Southeast and Midwest regions, where prevalence rates of up to 40% were found. Among animals, mammals and birds exhibited the highest prevalence.

During 2009-2012, wild animals were sampled in the Amazon biome of Brazil. Animal tissues and blood were tested by polymerase chain reaction (PCR) assays targeting DNA of the bacterial family Anaplasmataceae (genera Anaplasma, Ehrlichia, Wolbachia) and the genus Borrelia. Overall, 181 wild animals comprising 36 different species (2 reptiles, 5 birds, and 29 mammals) were sampled. All birds and reptiles were negative by all PCR assays, as well as all mammals for the Borrelia PCR assay. Anaplasmataceae agents were searched by PCR assays targeting two different genes, the ribosomal 16S rRNA gene and the protein-coding dsb gene. Three dsb closely related haplotypes were generated from 3 white-lipped peccaries (Tayassu pecari). In a phylogenetic analysis inferred from dsb partial sequences, these haplotypes grouped with previously reported Ehrlichia haplotypes from jaguar (Panthera onca) and horse from Brazil, suggesting that they could all represent a single species, yet to be properly characterized. A unique dsb haplotype was generated from a sloth (Bradypus tridactylus), and could also represent a different Ehrlichia species. All these dsb haplotypes formed a clade sister to the Ehrlichia ruminantium clade. Three distinct 16S rRNA gene haplotypes were generated from a wild guinea pig (Cavia sp.), a woolly mouse opossum (Micoureus demerarae), and two from robust capuchin monkeys (Sapajus sp.). In a phylogenetic analysis inferred from 16S rRNA gene partial sequence, these haplotypes grouped within the Wolbachia clade, and are likely to represent Wolbachia organisms that were infecting invertebrate metazoarians (e.g., filarids) associated with the sampled mammals. Two deer (Mazama americana) samples yielded two distinct 16S rRNA gene sequences, one identical to several sequences of Anaplasma bovis, and an unique sequence that grouped in a clade with different Anaplasma species. Our results indicate that a variety of genetically distinct Anaplasmataceae organisms, including potentially new Ehrlichia species, circulate under natural conditions in the Amazonian wildlife.

Little information is available on the occurrence and genetic variability of the diarrhoea-causing enteric protozoan parasite Giardia duodenalis in indigenous communities in Brazil. This cross-sectional epidemiological survey describes the frequency, genotypes, and risk associations for this pathogen in Tapirapé people (Brazilian Amazon) at four sampling campaigns during 2008–2009. Microscopy was used as a screening test, and molecular (PCR and Sanger sequencing) assays targeting the small subunit ribosomal RNA, the glutamate dehydrogenase, the beta-giardin, and the triosephosphate isomerase genes as confirmatory/genotyping methods. Associations between G. duodenalis and sociodemographic and clinical variables were investigated using Chi-squared test and univariable/multivariable logistic regression models. Overall, 574 individuals belonging to six tribes participated in the study, with G. duodenalis prevalence rates varying from 13.5–21.7%. The infection was positively linked to younger age and tribe. Infected children <15 years old reported more frequent gastrointestinal symptoms compared to adults. Assemblage B accounted for three out of four G. duodenalis infections and showed a high genetic diversity. No association between assemblage and age or occurrence of diarrhoea was demonstrated. These data indicate that the most likely source of infection was anthropic and that different pathways (e.g., drinking water) may be involved in the transmission of the parasite.

Prevalence of Toxoplasma gondii and Neospora caninum antibodies in sera of 325 dogs in 11 villages inhabited by the Tapirapé and Karajá ethnic groups in the south of the Brazilian Amazon was determined by the use of an indirect fluorescence antibody test. Antibodies (cutoff 1:16) to T. gondii were found in 169 (52%) and to N. caninum (cut-off 1:50) in 32 (9.8%) of 325 dogs. Seropositivity for both parasitic infections was widely prevalent in dogs from these villages and was higher in older dogs, indicating post-natal transmission.