A cross - sectional investigation on the molecular infection rate and subtype distribution of Blastocystis among diarrhea patients in Zhuhai, Southern Guangdong Province, China.

INTRODUCTION

Blastocystis sp. is a common zoonotic protozoan found in both humans and animals. Epidemiological investigations seldom concentrate on this parasite, frequently underestimating its medical significance. The current study determined the presence and genetic characteristics of Blastocystis sp. in diarrheal patients from Zhuhai City, China.

METHODS

A total of 283 fecal samples were collected from diarrheal patients for DNA extraction. Blastocystis subtypes (STs) were identified by analyzing the DNA sequences of the small ribosomal subunit of the parasite isolates.

RESULTS

The overall infection rate of Blastocystis among the patients was 4.9% (14/283). The infection rate of Blastocystis was significantly higher in female patients (8.1%) than in male patients (2.9%); it was also higher in the elderly (6.3%) and adults (6.7%) compared to children (2.9%), although the difference was not statistically significant. Additionally, the infection rates of Blastocystis in rural (5.0%) and urban (4.9%) areas were consistent. Three known STs, including ST1 (n = 5), ST2 (n = 1) and ST3 (n = 8) were identified. A total of nine sequences were obtained across the three STs of Blastocystis, including four known and five novel sequences.

CONCLUSIONS

This study is the first to report on the distribution of Blastocystis STs among individuals with diarrhea in Zhuhai, China, revealing potential transmission of the parasite both from human-to-human and from animals to humans. Given the ongoing debate regarding the pathogenicity of Blastocystis, it is recommended that patients suffering from diarrhea be closely monitored to identify and address the underlying causes, thereby enhancing their health outcomes.