One health survey of Enterocytozoon bieneusi in rural Adana (Türkiye) reveals zoonotic genotypes and two novel ITS genotypes in livestock

Enterocytozoon bieneusi is the most frequently detected microsporidian in humans and infects a wide range of animals. Data integrating human, animal, and environmental compartments under a One Health framework remains scarce. We conducted a molecular survey in a rural area of Adana Province, south-central Türkiye (October–November 2023). A total of 394 samples were screened, including stool from apparently healthy individuals (n = 124) from 64 households and livestock such as cattle (n = 75), sheep (n = 95), goats (n = 60) and environmental samples (lake water, n = 24; mud, n = 16). Detection and genotyping targeted the Internal Transcribed Spacer (ITS) region by nested PCR and Sanger sequencing. No human or environmental samples were positive, this result may be influenced by sampling limitations, seasonality, and methodological sensitivity rather than reflecting true absence. Overall E. bieneusi prevalence in livestock was 5.2% (12/230; 95% CI, 2.6–8.6). By host, prevalence was 8.4% in sheep (8/95; 95% CI, 3.7–15.9), 3.3% in goats (2/60; 95% CI, 0.4–11.5), and 2.7% in cattle (2/75; 95% CI, 0.3–9.3); differences were not statistically significant. Sequence analysis identified three known genotypes: BEB6 (6/12), J (1/12), and Type IV (1/12), and two novel genotypes (ShTrEb1, ShTrEb2; 2/12 each). J and Type IV were restricted to cattle; BEB6 and ShTrEb1 occurred in sheep and goats; ShTrEb2 was detected only in sheep. Phylogenetic analysis placed Type IV in Group 1 and BEB6, J, ShTrEb1, and ShTrEb2 in Group 2. Although humans and environmental matrices tested negative in this study, the detection of genotypes in livestock should be interpreted carefully and highlights the need for further studies to clarify potential transmission pathways. Larger, seasonally stratified surveys with standardized environmental methods are warranted to better understand regional transmission dynamics.