Recurrent zoonotic Cryptosporidium parvum transmission at an animal-contact visitor attraction: insights into infection prevention and control, South West England (2023-2025).

Between 2023 and 2025, four outbreaks of zoonotic Cryptosporidium parvum infection involving 39 laboratory-confirmed cases occurred at a single animal-contact visitor attraction in South West England. A retrospective outbreak investigation, incorporating elements of a descriptive case series, was undertaken to identify factors associated with repeated transmission and to draw insights for infection prevention and control. The study integrated epidemiological, veterinary, environmental, and molecular data, including exposure questionnaires, animal faecal testing, environmental sampling, observational assessments, and genotyping of human and animal isolates. Zoonotic gp60 subtype IIaA15G2R1 predominated across outbreaks. In the fourth outbreak, identical gp60 subtypes and shared multiple-locus variable-number tandem-repeat analysis alleles in lamb and human samples supported zoonotic transmission. Environmental sampling identified faecal indicator organisms and Shiga toxin-producing E.coli on high-touch surfaces. An observational assessment identified frequent opportunities for faecal-oral exposure during close contact with young ruminants. Despite compliance with industry standards, persistent environmental contamination, in-pen contact, and child behavioural factors were identified as plausible contributors to transmission. These findings highlight the challenges of preventing zoonotic infection in this setting and support refinement of existing guidance.