Molecular and descriptive epidemiology of intestinal protozoan parasites of children and their pets in Cauca, Colombia: a cross-sectional study

Ximena Villamizar,Giovanny Herrera,Juan David Ramírez,Julio Cesar Giraldo,Myriam Consuelo Lopez,Lorena Buitron,Fabiola E Gonzalez-C,Lina Maria Muñoz,Adriana Higuera,Luis Reinel Vasquez-A

doi:10.1186/s12879-019-3810-0

Ximena Villamizar, Giovanny Herrera + Show 8 more

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https://doi.org/10.1186/s12879-019-3810-0

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Abstract

BackgroundParasitic infections, particularly those caused by protozoa, represent a considerable public health problem in developing countries. Blastocystis, Giardia duodenalis, Cryptosporidium spp. and the Entamoeba complex (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) are the most common etiological causes of intestinal parasitic infections.MethodsWe carried out a descriptive cross-sectional study in school-age children attending a daycare institution in commune eight of Popayán, Cauca (Southwest Colombia). A total of 266 fecal samples were collected (258 from children and eight from pets). Blastocystis, G. duodenalis, Cryptosporidium spp. and the Entamoeba complex were identified by microscopy, quantitative real-time PCR (qPCR) and conventional PCR. The concordance of qPCR and microscopy was assessed using the Kappa index. Molecular characterization was conducted to identify Blastocystis subtypes (18S), G. duodenalis assemblages (tpi and gdh) and Cryptosporidium species/subtypes (18S and GP60). Potential associations between intestinal parasitism and sociodemographic factors were examined using bivariate analyses.ResultsA total of 258 fecal samples from children were analyzed by microscopy and 255 samples were analyzed by qPCR. The prevalence of Blastocystis was between 25.19% (microscopy) and 39.22% (qPCR), that of G. duodenalis was between 8.14% (microscopy) and 10.59% (qPCR), that of Cryptosporidium spp. was estimated at 9.8% (qPCR), and that of the Entamoeba complex was between 0.39% (conventional PCR) and 0.78% (microscopy). The concordance between microscopy and qPCR was very low. Blastocystis ST1 (alleles 4, 8, and 80), ST2 (alleles 11, 12, and 15), ST3 (alleles 31, 34, 36, 38,57, and 151), and ST4 (alleles 42 and 91), G. duodenalis assemblages AII, BIII, BIV and D, C. parvum subtype IIa and C. hominis subtype IbA9G3R2 were identified. The only identified member of the Entamoeba complex corresponded to E. histolytica. No statistically significant association was identified between parasitic infection and any sociodemographic variable.ConclusionThis study revealed the usefulness of molecular methods to depict the transmission dynamics of parasitic protozoa in southwest Colombia. The presence of some of these protozoa in domestic animals may be involved in their transmission.

Highlights

Parasitic infections, those caused by protozoa, represent a considerable public health problem in developing countries
Prevalence of intestinal parasitic infection A total of 258 human fecal samples were analyzed by microscopy and 255 were analyzed by PCR
Evaluation of polyparasitism We found that among the stool samples analyzed by quantitative real-time PCR (qPCR) and conventional PCR, approximately 36% of individuals were infected by a single parasite, 11% were infected by two parasites and 1% were infected by three parasites (Fig. 2a)

Summary

Introduction

Those caused by protozoa, represent a considerable public health problem in developing countries. Blastocystis, Giardia duodenalis, Cryptosporidium spp. and the Entamoeba complex (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) are the most common etiological causes of intestinal parasitic infections. Infections by Intestinal parasites occur worldwide, and their high prevalence rates represent a major public health problem. The major pathogens responsible for intestinal parasitic infections are protozoa. These microorganisms can cause significant morbidity in children as well as opportunistic infections in immunosuppressed patients [1]. Blastocystis, Giardia duodenalis ( known as Giardia intestinalis and Giardia lamblia), Cryptosporidium spp. and members of the Entamoeba complex (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) impose major burdens of diarrheal disease in children. The primary modes of protozoan parasite transmission are the fecal-oral route after direct or indirect contact with the infective forms (cysts/oocysts), human to human transmission, animal to human transmission, transmission by water, transmission through contaminated food, and airborne transmission (for Cryptosporidium spp. only) [3, 4]

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