Diversity, geographical distribution, and prevalence of Entamoeba spp. in Brazil: a systematic review and meta-analysis.

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.

TITLE: Diversité, répartition géographique et prévalence d'Entamoeba spp. au Brésil : revue systématique et méta-analyse. ABSTRACT: Le genre Entamoeba comprend une variété d'espèces largement distribuées, adaptées à vivre dans le tube digestif des humains et une grande variété d'animaux de différentes classes. L'objectif de cette étude était d'étudier la prévalence, la distribution et l'épidémiologie moléculaire d'Entamoeba spp. dans différentes classes d'hôtes au Brésil. Les études qui ont analysé les hôtes de plusieurs classes, y compris les humains et les animaux domestiques, sauvages ou captifs, ont été prises en compte. La prévalence combinée d'Entamoeba spp. a été calculée à l'aide du modèle à effets aléatoires. Au total, 166 études sur l'homme et 16 sur les animaux ont été incluses. La prévalence d'Entamoeba spp. dans la population brésilienne était de 22 % (IC à 95 % : 21­24). L'état avec la prévalence la plus élevée était Paraiba avec 72 %, suivi du District fédéral avec 53 % et Rondonia avec 50 %. Chez les patients immunodéprimés, la prévalence était de 18 % et le cancer (36 %) était la cause la plus fréquente d'immunosuppression. La prévalence d'Entamoeba spp. chez les hôtes animaux était de 12 % (IC à 95 % : 7­17). Les animaux sauvages en captivité et les animaux domestiques d'élevage ont affiché la prévalence la plus élevée, avec respectivement 16 % et 15 %. Les espèces trouvées le plus souvent étaient E. coli (86,5 %), E. dispar (7,9 %) et E. histolytica (3,1 %). En conclusion, une prévalence élevée (22 %) d'Entamoeba spp. a été trouvée dans la population brésilienne, allant jusqu'à 50 % principalement dans les régions du nord, du nord-est et du centre-ouest. L'espèce pathogène E. histolytica est répartie dans la plupart des régions du Brésil, avec des pourcentages de prévalence importants. Parmi les animaux, les espèces d'Entamoeba non identifiées étaient les plus répandues chez les mammifères.

Multilocus Genotyping of Giardia duodenalis in Mostly Asymptomatic Indigenous People from the Tapirapé Tribe, Brazilian Amazon.

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 Blastocystis sp. infection in several hosts in Brazil: a systematic review and meta-analysis.

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.