Epidemiology, species composition and genetic diversity of tetra- and octonucleated Entamoeba spp. in different Brazilian biomes

Abstract

Background Entamoeba species harbored by humans have different degrees of pathogenicity. The present study explores the intra- and interspecific diversity, phylogenetic relationships, prevalence and distribution of tetra- and octonucleated cyst-producing Entamoeba in different Brazilian regions. Methods Cross-sectional studies were performed to collect fecal samples (n = 1728) and sociodemographic data in communities located in four Brazilian biomes: Atlantic Forest, Caatinga, Cerrado, and Amazon. Fecal samples were subjected to molecular analysis by partial small subunit ribosomal DNA sequencing (SSU rDNA) and phylogenetic analysis. Results Light microscopy analysis revealed that tetranucleated cysts were found in all the studied biomes. The highest positivity rates were observed in the age group 6–10 years (23.21%). For octonucleated cysts, positivity rates ranged from 1 to 55.1%. Sixty SSU rDNA Entamoeba sequences were obtained, and four different species were identified: the octonucleated E. coli, and the tetranucleated E. histolytica, E. dispar, and E. hartmanni. Novel haplotypes (n = 32) were characterized; however, new ribosomal lineages were not identified. The Entamoeba coli ST1 subtype predominated in Atlantic Forest and Caatinga, and the ST2 subtype was predominant in the Amazon biome. E. histolytica was detected only in the Amazon biome. In phylogenetic trees, sequences were grouped in two groups, the first containing uni- and tetranucleated and the second containing uni- and octonucleated cyst-producing Entamoeba species. Molecular diversity indexes revealed a high interspecific diversity for tetra- and octonucleated Entamoeba spp. (H ± SD = 0.9625 ± 0.0126). The intraspecific diversity varied according to species or subtype: E. dispar and E. histolytica showed lower diversity than E. coli subtypes ST1 and ST2 and E. hartmanni. Conclusions Tetra- and octonucleated cyst-producing Entamoeba are endemic in the studied communities; E. histolytica was found in a low proportion and only in the Amazon biome. With regard to E. coli, subtype ST2 was predominant in the Amazon biome. The molecular epidemiology of Entamoeba spp. is a field to be further explored and provides information with important implications for public health.

High prevalence of protozoan infections: a permanent cycle in a brazilian semi-arid peripheric area

“…Intestinal protozoan infections are closely related to inadequate sanitation and environmental contamination with fecal matter (Calegar et al, 2021). In this study, a parasitic prevalence of 45.9% was detected in children and adolescents, predominantly protozoan infections.…”

“…The differentiation between E. dispar/ E. moshkovskii was not performed because of the need to apply molecular diagnosis. Molecular epidemiological studies showed that E. dispar is the species most commonly found among the tetra-nucleated cysts (Santos et al, 2014, Calegar et al, 2021. The prognosis for patients with nonpathogenic protozoa is excellent, as most patients are asymptomatic (Calegar et al, 2021).…”

“…Molecular epidemiological studies showed that E. dispar is the species most commonly found among the tetra-nucleated cysts (Santos et al, 2014, Calegar et al, 2021. The prognosis for patients with nonpathogenic protozoa is excellent, as most patients are asymptomatic (Calegar et al, 2021). According to Haidar & De Jesus (2021), treatment is not indicated for E. coli infection, supportive care should be provided for patients, and proper hygiene should be maintained.…”

“…Entamoeba species harbored by the human digestive tract have different degrees of pathogenicity and impact on public health. Although some species are considered commensal and non-pathogenic, E. histolytica can cause serious, life-threatening, and invasive infections such as amoebic dysentery and liver abscess (Calegar et al, 2021). E. histolytica produces tetra-nucleated cysts, which are indistinguishable from those produced by E. dispar.…”

Multiplex Serology for Measurement of IgG Antibodies Against Eleven Infectious Diseases in a National Serosurvey: Haiti 2014–2015

“…In this study population, seropositivity to the E. histolytica LecA antigen peaked around 10 years of age, though IgG levels also slowly increased with persons' age. The use of this antigen to assess E. histolytica serology has been very limited but has shown clear increases in seroconversion during the first years of life ( 35 ), which mirrors exposure dynamics to this parasite in children ( 51 , 52 ).…”