Dados do Trabalho

Título

Neglected gut protozoa: exploring genetic diversity and epidemiologic profiles in distinct Brazilian biogeographic regions

Introdução

Gut protozoan parasites are neglected and not targeted by initiatives such as mass treatments with anthelmintic drugs, leading to a knowledge gap concerning their diversity and epidemiology. Giardia duodenalis is associated with malnutrition in children, and Entamoeba species have different degrees of pathogenicity.

Objetivo(s)

To explore the intra- and interspecific diversity, phylogenetic relationships, prevalence and distribution of G. duodenalis and Entamoeba spp. in different Brazilian regions.

Material e Métodos

Cross-sectional studies were performed to collect fecal samples (n=1728 for Entamoeba spp.; n=1334 for G. duodenalis) and sociodemographic data in communities located in Atlantic Forest, Caatinga, Cerrado, and Amazon. Positive fecal samples were subjected to molecular analysis by partial small subunit ribosomal DNA and β-giardin gene sequencing for Entamoeba spp. and G. duodenalis characterization, respectively.

Resultados e Conclusão

Concerning G. duodenalis, prevalence reached 17.8% (64/360) in the Amazon, 8.8% (48/544) in the Atlantic Forest, 7.4% (22/299) in Cerrado and 2.3% (3/131) in the Semiarid. In the Amazon, assemblage B was the most frequently detected, predominantly BIII, and with two novel sub-assemblages. Assemblage A predominated in the extra-Amazon region, with five novel sub-assemblages. Regarding Entamoeba spp., 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. 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. Conclusions. G. duodenalis is endemic in Brazilian communities in different biogeographic regions, presenting high genetic diversity and a heterogeneous genotypic distribution. Tetra- and octonucleated cyst-producing Entamoeba are also endemic in the studied communities; E. histolytica was found in a low proportion and only in the Amazon biome. Entamoeba coli ST2 was predominant in the Amazon biome. The molecular epidemiology of Entamoeba spp. and G. duodenalis is a field to be further explored and provides information with important implications for public health.

Palavras-chave

Entamoeba spp.; Giardia duodenalis; Genotypes