Blastocystis is one of the most common protozoa found in the human gut and are genetically diverse and widely distributed around the world. Nonspecific and inconsistent symptoms have been associated with this protozoon; thus, its clinical importance remains controversial. Our aim was to estimate the relative frequency of Blastocystis subtypes 1, 2, and 3, which are the predominant subtypes reported in South America, based on conserved regions of SSU rDNA sequences and determine the factors associated with them. A total of 116 Blastocystis-positive stool samples were processed using conventional PCR with Blastocystis-specific primers. We identified subtype 1 (10.3%), subtype 2 (7.8%), subtype 3 (25.0%), and mixed subtype infections (8.7%). However, we could not identify any Blastocystis subtypes in 48.3% of the samples; therefore, it is likely that other subtypes were present in the area. No association was found between any gastrointestinal symptom and single or mixed Blastocystis subtypes. We found a statistically significant association between Blastocystis subtype 2 and irritable bowel syndrome (OR = 17.8, 95% CI = 1.5–408.4, p = 0.039); however, the number of samples with IBS was small (n= 4). There was no association between the Blastocystis subtypes and any epidemiological variable studied. In rural populations, we only identified subtype 1, while in urban and periurban populations, we identified subtypes 1, 2, and 3.

Blastocystis is one of the most common protozoa in the human gut and a zoonotic organism related to unsanitary living conditions. This protozoon shows a broad distribution, unclear symptomatology, and undefined pathogenicity. In Peru, studies report the presence of Blastocystis in many regions, but the highest prevalence levels are reported in Arequipa. The aim of this study was to link Blastocystis infection with social determinants of health. We recruited and surveyed 232 infected and uninfected participants from houses with at least one Blastocystis-infected person. All samples were concentrated by spin concentration method in saline solution, examined by wet mount under light microscopy and confirmed with methylene-stained stool smear. We found a human Blastocystis prevalence of 51.3% in the study sample. We also found statistical associations between Blastocystis infection and peri-urban location in the city as well as the use of alternative non-domiciliary water supplies, suggesting these are risk factors for human Blastocystis infection.

Blastocystis is one of the most common protozoa in the human gut and is a zoonotic parasite related to unhealthy living conditions. This parasite shows a broad distribution, unclear symptomatology, and undefined pathogenicity. In Peru, studies report the presence of Blastocystis in many regions, but the highest prevalence levels are reported in Arequipa. The aim of this study was to link Blastocystis infection with social determinants of health. We recruited and survey 232 participants from infected and uninfected homes. All samples were analyzed by direct microscopy and confirmed with methylene-stained stool smear. We found a human Blastocystis prevalence of 51.3% in the study sample. We also found statistical associations between Blastocystis infection and the use of alternative non-domiciliary water supplies as well as the use of latrine for body-waste disposal, suggesting these are risk factors for human Blastocystis infection.

Blastocystis is one of the most common parasites found in the gut of humans and other hosts. It has a wide genetic diversity distributed around the world, predominating subtypes 1, 2 and 3 in South America countries. Nonspecific and inconsistent symptoms associated with this parasite made it controversial. The aim of this study was to estimate the prevalence of subtypes and determinate the epidemiological conditions associated with them. A total of 116 Blastocystis positive stool samples were processed by conventional PCR with Blastocystis-specific primers for subtypes 1 to 3. We identified subtype 1 (10.3%), subtype 2 (7.6%), subtype 3 (25.0%) and mixed infections (8.6%). We did not identify these Blastocystis subtypes in 48.7% of stool samples, assuming the presence of other subtypes in the zone. Any association was found between gastrointestinal symptoms and single subtype infections neither with mixed subtypes coinfections. However, our results suggest an association of Blastocystis subtype 2 and Irritable Bowel Syndrome (IBS, p=0.039). Besides, there was not an association between Blastocystis subtypes 1, 2 and 3 nor-mixed infections with epidemiological variables such as gender, age, presence of animals or vectors, places of food consumption, type of water consumption and water supply.