1. . A total of 355 eligible cases (from 542 questionnaires) were identified which were not from an outbreak, not associated with foreign travel and had no other household members with diarrhoea. Permission was sought to follow up farm animal or environmental exposures. The contact animal and environmental samples were analysed for the presence of Cryptosporidium oocysts by immunomagnetic separation and immunofluorescence microscopy (IFM), PCR-RFLP at the 18s rRNA locus, PCR at the dhfr locus and analysis of part of the GP60 gene. Sequencing was used to confirm speciation results and for GP60 subtyping. ZOONOTIC TRANSMISSION OF CRYPTOSPORIDIUM - A 2-YEAR EPIDEMIOLOGICAL STUDY Smith, R.P. 1, Chalmers, R.M. 3, Elwin, K. 3, Hadfield, S. 3, Mueller-Doblies, D. 2, Clifton-Hadley, F.A. 2, Watkins, J. 4 and Giles, M. 2 (1) Centre for Epidemiology and Risk Analysis (CERA), Veterinary Laboratories Agency Weybridge (VLA), New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom (2) Food and Environmental Safety (FES), Veterinary Laboratories Agency Weybridge (VLA), New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom (3) UK Cryptosporidium Reference Unit, NPHS Microbiology Swansea, Singleton Hospital, Swansea, SA2 8QA, United Kingdom (4) CREH Analytical, Leeds, LS18 4RS. Method: Between Nov 2004 and Nov 2006, 28 diagnostic laboratories, in 41 local authorities within the study areas of South West and East England and Wales, submitted 1030 human Cryptosporidium-positive faecal samples to the UK Cryptosporidium Reference Unit for species/subtype identification by PCR-RFLP and sequencing. Human cases were asked by the Local Authority Environmental Health Department to complete questionnaires, to identify cases reporting farmed animal contact or key environmental exposures (manure, slurry, private water supply). Introduction: Cryptosporidium is an important protozoan parasite which can cause diarrhoeal disease in humans. In healthy individuals it is usually self- limiting, but can be fatal in immunocompromised patients. There are two principal species which cause human disease in the UK:Cryptosporidium parvum and Cryptosporidium hominis, which between them account for 96 per cent of cases in approximately equal proportions. C. parvum is considered to be a zoonotically acquired infection, while C. hominis is generally considered to be primarily spread within human populations. Both species can be transmitted directly or indirectly e.g. waterborne. The relative risk of human infection through direct or indirect contact with animals or animal faeces during occupational or recreational activities is largely unknown. Results: 88/355 (24.8%) eligible human cases reported farm/ environment contact and 38 gave permission to contact the farmers for further sampling. 144/371 (38.8%) farm animal samples were positive for Cryptosporidium by IMS-IFM and/or PCR analysis. Of those tested and positive by PCR, 47/63 (74.6%) were C. parvum, 4 were C. bovis, 1 C. andersoni, 1 unusual type and 10 unclear patterns. Sampling consent was given by the farmers in 22/38 cases. 371 samples were collected from the 22 contact farms Of the 22 human cases which were followed up by a farm visit, 18 were positive for C. parvum (predominantly GP60 allele IIa) The 5 matched GP60 subtypes were all IIaA17G1R1, originating from 1 farm dog, 10 cattle and 2 sheep. In 5 of the human cases, the human subtype matched the animal subtypes Conclusion: Our data provides molecular evidence of matched species and subtypes in humans and animals, who had recent contact, to support the evidence of a zoonotic transmission pathway of C. parvum through direct or indirect contact with farm animals Acknowledgements: The authors would like to thank collaborating colleagues at VLA and CRU. This study was funded by Defra under project OZ0407 Cryptosporidium species in subset of eligible human cases Farm animal sampling results Cryptosporidium species comparison Aim: This study investigated the relationship between Cryptosporidium isolates of human origin and isolates from animal and environmental contacts in the two weeks prior to the onset of symptoms. By analysing the Cryptosporidium species and subtypes present in the human cases and their animal contacts we addressed the question of whether the human infection could have been caused by zoonotic transmission. For further information contact Centre for Epidemiology and Risk Analysis An Executive Agency of the m.giles@vla.defra.gsi.gov.ukm.giles@vla.defra.gsi.gov.ukVeterinary Laboratories Agency-Weybridge, Department for Environment, Food & r.smith@vla.defra.gsi.gov.uk r.smith@vla.defra.gsi.gov.uk Addlestone, Surrey KT15 3NB, UK. Rural Affairs Tel. 01932 34111 www.defra.gov.uk/corporate/vla Figure 1: Cryptosporidium species from eligible human cases The table below shows the speciation results of all human cases and those that were eligible for the study, with or without risk exposure. Figure 1 shows the percentage breakdown of species for eligible cases. Human cases reporting either farm animal or environmental contact were significantly more likely to have C. parvum than the rest of the study population (Chi-squared test P<0.001).