PCR analysis of the ITS gene identified E. bieneusi in four samples (). DNA sequencing of the PCR products identified the presence of three genotypes. Two of the genotypes were known ones, D (in two isolates) and K (in one isolate), and one had two nucleotide substitutions comparing to genotype K (in one isolate). Among the four E. bieneusi-positive children, three had diarrhoea and one did not have diarrhoea ().
Showing the prevalence of Enterocytozoon bieneusi isolates from Nigerian children.
While in this pilot study, only a small number of children were found positive for E. bieneusi
, the genotype and subtype diversity of the parasite was high, suggesting that there was intensive transmission of microsporidiosis in this area. The source of E. bieneusi
in the studied children is not known. However, both genotypes D and K identified in the study have been previously detected in both immunocompromised and immunocompetent patients and domestic animals. [1
] While, these genotypes could be of animal origin, a data from Cryptosporidium
investigation conducted on the same group of patient [8
] suggests a strong possibility of anthroponotic transmission of these two E. bieneusi
genotypes in the study area. More systematic collection of epidemiological data and sampling of animals, drinking water, and fresh produce are needed to clarify the source of E. bieneusi
in Nigerian children.
Geographically isolated E. bieneusi genotypes/subtypes are probably circulating in Nigerian children, and even one of the E. bieneusi genotypes represents a new genotype.
In conclusion, our study reports high genotype and subtype diversity of E. bieneusi and also suggests that anthroponotic transmissions may play a significant role in the epidemiology of microsporidiosis. More studies are needed on the source and transmission of microsporidiosis in Nigeria and in other developing countries.