Giardiasis is a parasitic infection that affects around 200 million people worldwide. This parasite presents a remarkable genetic variability observed in 8 genetic clusters named as 'assemblages' (A-H). These assemblages are host restricted and could be zoonotic where A and B infect humans and animals around the globe. The knowledge of the molecular epidemiology of human giardiasis in South-America is scarce and also the usefulness of PCR to detect this pathogen in fecal samples remains controversial. The aim of this study was to conduct a cross-sectional study to compare the molecular targets employed for the molecular diagnosis of Giardia DNA and to discriminate the parasite assemblages circulating in the studied population. We analyzed 181 fecal samples from Children at La Virgen, Cundinamarca, Colombia that were DNA-extracted and analyzed by SSU rDNA, tpi and gdh loci. We observed positivity by microscopy of 13% and by PCR around 76-80% depending on the molecular marker. Additionally, a lack of statistical concordance between microscopy and PCR was detected. Regarding the genetic assemblages, we detected assemblage A (3%), assemblage B (90%) and mixed infections assemblages A+B (7%). Hence, the sub-assemblages were typed as AI, AII, BIII and BIV across the population. This study represents a reliable attempt to understand the molecular epidemiology of giardiasis in Colombia and the use of PCR to detect cryptic infections. The epidemiological implications are herein discussed.

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We conducted an observational study to determine the prevalence of Entamoeba spp., in samples collected in a waste water treatment plant that provides water for agricultural irrigation. Samples were collected weekly over a period of 10 weeks at representative contamination stages from within the treatment plant. Protozoan identification was performed via light microscopy and culture. PCR amplification of small subunit rRNA gene sequences of E. histolytica/dispar/moshkovskii was performed in culture positive samples. Light microscopy revealed the presence of Entamoeba spp., in 70% (14/20) of the raw waste water samples and in 80% (8/10) of the treated water samples. PCR amplification after culture at both 24 and 37°C revealed that 100% (29/29) of the raw waste water samples and 78.6% (11/14) of the treated waste water were positive for E. moshkovskii. We report the first isolation of E. moshkovskii in Colombia, confirmed by PCR. Recent reports of E. moshkovskii pathogenic potential suggest this finding could constitute a public health risk for people exposed to this water.

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