Exploring Blastocystis genetic diversity in rural schoolchildren from Colombia using next-generation amplicon sequencing reveals signifcant associations between contact with animals and infection risk

Authors: HERNÁNDEZ, PAULA - El Bosque University; Maloney, Jenny; Molokin, Aleksey; George, Nadja; MORALES, LILIANA - El Bosque University; CHAPARRO-OLAYA, JACQUELINE - El Bosque University; Santin-Duran, Monica

Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2023
Publication Date: 5/9/2023
Citation: Hernández, P.C., Maloney, J.G., Molokin, A., George, N.S., Morales, L., Chaparro-Olaya, J., Santin, M. 2023. Exploring Blastocystis genetic diversity in rural schoolchildren from Colombia using next-generation amplicon sequencing reveals signifcant associations between contact with animals and infection risk. Parasitology Research. 122(7):1451-1462. https://doi.org/10.1007/s00436-023-07841-3.
DOI: https://doi.org/10.1007/s00436-023-07841-3

Interpretive Summary: Blastocystis is a common intestinal protist found in humans and many other animals globally. However, many questions about the status of Blastocystis as a pathogen, the risk factors associated with its transmission, and its zoonotic potential have yet to be answered. In the present study, we explored subtype (ST) diversity and potential risk factors for Blastocystis infection in children from a rural area of Colombia. Ninety-eight samples were tested for Blastocystis via PCR, and ST identification was performed through next generation amplicons sequencing (NGS). Logistic regression analyses were used to test for associations between the presence of Blastocystis and individual STs and sociodemographic variables. Overall, 72.4% of samples were Blastocystis-positive. Among positive samples, five STs (ST1-ST5) were observed with ST1, ST2, and ST3 found in nearly equal proportions (~ 40%) and ST4 (1.4%) and ST5 (5.6%) less commonly observed. Mixed ST infection was also common and observed in 28.2% of positive samples. Children living within the same household were found to share ST profiles in some cases, but diverse ST profiles within the same household were also observed. Significant associations were observed for several risk factors. However, the presence of animals was one of the most common factors associated with Blastocystis in this study. The data from this study are important for understanding the routes of infection and risk factors that may influence Blastocystis transmission and can help to define how different between STs may differ in pathogenicity and zoonotic transmission potential.This study provides beneficial information to other scientists, physicians, and public health agencies concerned with this widespread parasite.

Technical Abstract: Blastocystis is a common intestinal protist with a global distribution in humans and many other animals. Yet, the status of Blastocystis as a pathogen, the risk factors associated with its transmission, and its zoonotic potential remain ill-defined. Here, we explored subtype (ST) diversity and potential risk factors for Blastocystis infection in 98 children from Apulo, Colombia. Samples were screened for Blastocystis via PCR, and ST identification was performed through next generation amplicons sequencing (NGS). Associations between the presence of Blastocystis and individual STs and sociodemographic variables were assessed via logistic regression analyses. Seventy-one samples (72.4%) were Blastocystis-positive, and NGS revealed the presence of five STs (ST1-ST5). ST1, ST2, and ST3 were common and observed in nearly equal proportions (~ 40%), while samples with ST4 (1.4%) and ST5 (5.6%) were comparatively rare. The presence of mixed STs in the same sample was also common (28.2%). Comparisons among children within the same household identified that shared ST profiles were common, but diversity within family units was also observed. Logistic regression analyses returned significant associations between the presence of Blastocystis, individual subtypes, or mixed subtypes for several variables. Intriguingly, the presence of animals was one of the most common significant associations. Taken together these data represent an important inroad in understanding both the potential routes and risk factors that may influence Blastocystis transmission and will be useful in shaping future studies which seek to clarify the relationships between STs, pathogenicity, and zoonotic transmission.