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

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.

Enteric parasitic infections in children and dogs in resource-poor communities in northeastern Brazil: Identifying priority prevention and control areas

“…In the last 20 years, several studies have emphasized that protozoan infections are a major challenge for Latin American children, including Brazilian children [12,13,16,38]. Our study confirms and expands upon these earlier efforts.…”

“…As for the risk factors for enteric parasites, children older than one year are at higher risk of infection. By that age children become exposed to more sources of environmental contamination [16,20,38]. There are also social determinants in the transmission of disease.…”

“…Giardia duodenalis and Ascaris lumbricoides are the enteric parasites most frequently found in Brazilian children [13,16], while in Brazilian dogs there is a greater prevalence of Ancylostoma [17,18]. Income level, education, sex and age are the main variables associated with these infections [19,20].…”

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

“…Valença-Barbosa et al [47] Valença-Barbosa et al [44] Faria et al [48] Carvalho-Costa et al [69] Santos et al [53] São Paulo…”

Genetic analysis of Giardia duodenalis isolates from children of low-income families living in an economically successful region in Southeastern Brazil

“…This frequency was lower than those recently reported in daycare and preschool children living in communities of São Paulo State, some of them placed in regions near the study area 8,16,17 . Recently, the examination of one fecal sample has revealed Giardia infection rates ranging from 2.7% to 11% in children of preschool age in some surveys worldwide [18][19][20][21] , including Brazil [22][23][24][25] . Even when the diagnosis is based on the examination of three stool samples, the studies did not report much higher prevalence rates 8,9,16,17 .…”