Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate's pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite's adaptations and potential implications for host health.
There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.
Blastocystis a single-celled eukaryotic protist, is known to inhabit the intestines of various hosts, including humans, and has been implicated in a wide spectrum of symptoms, ranging from gastrointestinal issues to skin disorders, thereby establishing its status as an emerging infectious agent. In this study, the prevalence of Blastocystis infection was investigated in insects, including cockroaches, houseflies, and crickets, as well as sea turtles. Additionally, the genotypic characteristics of the isolated Blastocystis strains were examined, and the evolutionary relationships between Blastocystis species found in sea turtles, and animals/humans were determined. Microscopic techniques and molecular methods were utilized in this study. The results showed that four out of 90 insects (4.44%) and one out of 13 sea turtles (7.7%) were infected by Blastocystis. Furthermore, detailed observations revealed the presence of characteristic morphological features, such as vacuolar forms in the cockroach, cricket and sea turtle samples and binary fission from cockroach samples, indicative of Blastocystis' mode of reproduction. While the ST8 of Blastocystis in sea turtles were successfully identified, no subtyping was achieved for the infected insects. This study not only establishes the occurrence of Blastocystis infection in sea turtles but also uncovers its ability to infect insects, suggesting a potential reservoir role for these organisms. Overall, this research emphasizes the significance of comprehending the prevalence, genotypic diversity, and evolutionary relationships of Blastocystis across various hosts. Such insights are instrumental in developing effective control measures and public health interventions to mitigate the associated symptoms and prevent future outbreaks.
Blastocystis is a ubiquitous waterborne parasite that has been implicated in some disease conditions including colorectal cancer and irritable bowel syndrome, and its surface coat characteristics have been associated with its pathogenicity. Although the morphology of Blastocystis isolates from human and animal sources have been studied, there is a paucity of data on the surface ultrastructure of Blastocystis isolated from water sources. Therefore, this study aimed to determine the occurrence and the ultrastructural surface of Blastocystis isolates from several water sources in Kedah and Penang, Malaysia. A total of 12 water samples were collected, namely, Pinang River and USM Harapan Lake all in Penang, whereas Lata Bayu Waterfall in Baling and UniSHAMS Lake, Kuala Ketil in Kedah. These were examined for Blastocystis by centrifugation and in vitro cultivation. Scanning electron microscopy (SEM) and light microscopy were employed to study the morphological characteristics and the surface ultrastructure of the parasite. Polymerase chain reaction (PCR) was carried out to obtain the subtypes (ST) of the positive Blastocystis isolates. The result revealed 25.0% (3/12) contamination with Blastocystis in which ST1, ST2, and an unknown ST (with a high similarity to ST1) were detected in water samples from the upstream, downstream, and midstream, respectively of Pinang River. Our study also revealed similarities in the sizes of the isolates from different river points, which were notably more diminutive compared to the sizes of the parasites observed in existing data from human and animal isolates. The surface characteristics showed a collection of single and dividing cells with smooth, folded surfaces enclosed in a film-like layer. Additionally, there were roundish, irregularly shaped cells with rough surfaces, and a woolly appearance. This study has added to our knowledge of the surface ultrastructure of Blastocystis and its possible contribution to the pathogenicity of the parasite.