Blastocystis sp. Infection: Prevalence and Clinical Aspects among Patients Attending to the Laboratory of Parasitology–Mycology of Fann University Hospital, Dakar, Senegal

Introduction: Blastocystis sp. is a unicellular obligate anaerobic protozoa found in the human intestinal tract. Its role in human health is widely discussed because of the high proportion of asymptomatic carriers. In sub-Saharan Africa, the prevalence of the disease is underestimated. This study was performed to describe the epidemiological, clinical, and parasitological aspects of Blastocystis sp. infection in patients attending to Fann University Hospital. Material and Methods: We carried out a retrospective and descriptive study among patients attending to the laboratory of Parasitology and Mycology of Fann University Hospital from January 2016 to December 2020. All stool samples collected were examined using direct examination, a formal ether concentration method, and a modified Zeilh–Nielsen staining method. A descriptive analysis was performed with Stata MP 16 software. The significance level was set at 5%. Results: Overall, 447 cases of Blastocystis sp. were reported in our study, representing a prevalence rate of 13.7% ((447/3264) (95% CI: 12.5–15.5)). The mean age of the patients was 26 ± 20.7 years. Subjects over 45 years of age were more affected, with a frequency of 14.7%. Blastocystis sp. carriage was more common in males, at 14.6%. The symptomatology was mainly represented by diarrhea, abdominal pain, and dyspeptic disorders. In asymptomatic patients, the frequency of Blastocystis sp. was 33.3%. Mono-infection was found in 78.6% of cases. In total, 96 patients were carriers of at least two parasites (21.5%). Blastocystis sp. was most associated with Entamoeba coli (8.1%) and Endolimax nanus (4.03%). The association with helminths was noted in 5 patients (3 Ascaris lumbricoides, Trichuris trichiura, and Taenia). Conclusion: These results show the frequency of Blastocystis sp. infection with a large proportion of asymptomatic carriers. The presence of the parasite in the stool, associated with digestive disorders or with the association of other intestinal parasites, could justify the initiation of an anti-parasitic treatment.