Intestinal parasite infections in a rural community of Rio de Janeiro (Brazil): Prevalence and genetic diversity of Blastocystis subtypes.

Carolina Valença Barbosa,Helena Lucia Carneiro Santos,Ricardo Pereira Igreja,Magali Muniz Barreto,Rosemary De Jesus Andrade,Claudia Masini D’Avila-Levy,Fernando Sodré,José Mauro Peralta,Heloisa Werneck De Macedo

doi:10.1371/journal.pone.0193860

Abstract

BackgroundIntestinal parasitic infections are considered a serious public health problem and widely distributed worldwide, mainly in urban and rural environments of tropical and subtropical countries. Globally, soil-transmitted helminths and protozoa are the most common intestinal parasites. Blastocystis sp. is a highly prevalent suspected pathogenic protozoan, and considered an unusual protist due to its significant genetic diversity and host plasticity.Methodology/main findingsA total of 294 stool samples were collected from inhabitants of three rural valleys in Rio de Janeiro, Brazil. The stool samples were evaluated by parasitological methods, fecal culture, nested PCR and PCR/Sequencing. Overall prevalence by parasitological analyses was 64.3% (189 out of 294 cases). Blastocystis sp. (55.8%) was the most prevalent, followed by Endolimax nana (18.7%), Entamoeba histolytica complex (7.1%), hookworm infection (7.1%), Entomoeba coli (5.8%), Giardia intestinalis (4.1%), Iodamoeba butchilii (1.0%), Trichuris trichiura (1.0%), Pentatrichomonas hominis (0.7%), Enterobius vermicularis (0.7%), Ascaris lumbricoides (0.7%) and Strongyloides stercoralis (0.7%). Prevalence of IPIs was significantly different by gender. Phylogenetic analysis of Blastocystis sp. and BLAST search revealed five different subtypes: ST3 (34.0%), ST1 (27.0%), ST2 (27.0%), ST4 (3.5%), ST8 (7.0%) and a non-identified subtype.Conclusions/significanceOur findings demonstrate that intestinal parasite infection rates in rural areas of the Sumidouro municipality of Rio de Janeiro, Brazil are still high and remain a challenge to public health. Moreover, our data reveals significant genetic heterogeneity of Blastocystis sp. subtypes and a possible novel subtype, whose confirmation will require additional data. Our study contributes to the understanding of potential routes of transmission, epidemiology, and genetic diversity of Blastocystis sp. in rural areas both at a regional and global scale.

Highlights

Intestinal parasitic infections (IPIs) are ubiquitous in humans, both in urban and rural environments from tropical and subtropical countries
We report a high prevalence of intestinal parasitic infections and a wide range of Blastocystis sp
We assessed the prevalence of IPIs and identity of Blastocystis sp. subtypes in a rural community of Rio de Janeiro, Brazil

Summary

Introduction

Intestinal parasitic infections (IPIs) are ubiquitous in humans, both in urban and rural environments from tropical and subtropical countries. In tropical developing countries, rural life is by itself associated with a high risk of infections due to negligible health knowledge, lower socio-economic conditions, inadequate environmental sanitation, insufficient water supply [5, 6] and higher contact rates with wildlife and domestic reservoirs of infection [7,8,9]. Presents pathogenic potential, its virulence mechanisms are not understood They infect a wide range of animals including birds, amphibians, reptiles, insects and mammals, including humans [13,14,15,16,17,18]. Intestinal parasitic infections are considered a serious public health problem and widely distributed worldwide, mainly in urban and rural environments of tropical and subtropical countries. Soil-transmitted helminths and protozoa are the most common intestinal parasites. Blastocystis sp. is a highly prevalent suspected pathogenic protozoan, and considered an unusual protist due to its significant genetic diversity and host plasticity

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Conclusion