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.

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.

O papel do cão como um hospedeiro definitivo de parasitoses intestinais com potencial zoonótico tem sido largamente reconhecido como um problema de saúde pública. Este trabalho analisou a prevalência e distribuição de enteroparasitas em fezes de cães de rua de oito cidades dos diferentes biomas nordestinos, com interesse de investigar a contaminação ambiental por enteroparasitas zoonóticos. 340 amostras fecais foram coletadas nos municípios de João Lisboa e Raposa (Maranhão), Piripiri e Domingos Mourão (Piauí), Fortaleza (Ceará), Petrolina (Pernambuco), Paulo Afonso e Salvador (Bahia). Deste total 43,2% resultaram positivas para alguma espécie de parasita intestinal. Maiores prevalências foram encontradas por ancilostomídeos com 43,5%, seguidos por Toxocara canis com 15%, Neospora sp. com 10,2% e Cryptosporidium sp. com 8,2%. Analisando a porcentagem de positividade por enteroparasitas nos quatro biomas da região Nordeste, o bioma Mata Atlântica foi o que apresentou maior prevalência (54,9%), seguido da Amazônia (54,3%), Caatinga (40,2%) e Cerrado (31,8%). O estudo da ocorrência e distribuição desses parasitas contribui com a vigilância epidemiológica das doenças enteroparasitárias e na aplicação de programas de saúde pública e veterinária para minimizarem a possibilidade de infecção e reinfecção dos animais e a transmissão para seres humanos.

The genus Entamoeba includes a variety of widely distributed species adapted to live in the digestive tracts of humans and a large variety of animals of different classes. The objective of this study was to investigate the prevalence, distribution, and molecular epidemiology of Entamoeba spp. in different classes of hosts in Brazil. Studies that analyzed hosts from several classes, including humans and domestic, wild, or captive animals, were considered. The pooled prevalence of Entamoeba spp. was calculated using the random-effects model. A total of 166 studies on humans and 16 on animals were included. The prevalence of Entamoeba spp. in the Brazilian population was 22% (95% CI: 21–24). The state with the highest prevalence was Paraiba with 72%, followed by Federal District with 53%, and Rondonia with 50%. In immunocompromized patients, the prevalence was 18%, and cancer (36%) was the most prevalent cause of immunosuppression. The prevalence of Entamoeba spp. in animal hosts was 12% (95% CI: 7–17). Captive wild animals and domestic farm animals showed the highest prevalence, with 16% and 15%, respectively. The species found more often were E. coli (86.5%), E. dispar (7.9%), and E. histolytica (3.1%). In conclusion, a high prevalence (22%) of Entamoeba spp. was found in the Brazilian population, with a prevalence of up to 50% mainly in the northern, northeastern, and central-western regions. The pathogenic species E. histolytica is distributed in most Brazilian regions, with significant prevalence percentages. Among animals, unidentified Entamoeba species were most prevalent in mammals.

Este trabalho teve por objetivo avaliar o percentual de positividade de Blastocystis spp. na população de quatro municípios de dois biomas do estado de Mato Grosso. As coletas de fezes foram realizadas nos municípios de Barão de Melgaço, Cáceres, Nova Xavantina e Cuiabá, nos biomas Pantanal e Cerrado. Foram coletadas 708 amostras fecais, o grupo amostral foi dividido em duas categorias sendo 350 provenientes do grupo I, o qual compreendia uma população composta por integrantes com idade entre 5 a 15 anos e 358 provenientes do grupo II, composto por integrantes com idade de 16 anos acima, destas 17,93% estavam positivas para Blastocystis spp, sendo que 11,15% eram amostras de pertencentes ao primeiro grupo e 6,77% referentes ao segundo grupo. Barão de Melgaço foi o município que apresentou a maior positividade (25,5%), e Cáceres a menor (7%). O bioma Cerrado apresentou um percentual maior de amostras positivas na população geral (21,10%) em relação ao Pantanal (15,5%). Houve diferença significativa para o percentual de positividade com relação à faixa etária, não havendo diferença entre os indivíduos por sexo ou por biomas. Este trabalho possibilitou um maior conhecimento sobre a realidade mato-grossense quanto à infecção por Blastocystis spp.