The molecular characterisation of Cryptosporidium species in relinquished dogs in Great Britain: a novel zoonotic risk?

Surveillance was conducted to investigate the occurrence of protozoan parasites of the genus Cryptosporidium in dogs newly admitted to a dog rehoming charity in London, Great Britain. Voided faecal samples were collected from all new admissions between 2011 and 2012 during six separate 4-week sampling periods. Information on host signalment, including age, breed and reason for submission and faecal consistency, was collected. Polymerase Chain Reaction (PCR) targeting the 18S ribosomal RNA gene, confirmed by sequencing, was conducted on the faecal samples to detect Cryptosporidium genomic DNA and determine Cryptosporidium identity. In total, 677 dogs were included in the study. The prevalence of Cryptosporidium-positive faecal samples was 4.6% (31/676). There were positive samples in all of the six sampling periods. Cryptosporidium canis (n = 28), C. parvum (n = 2) and C. andersoni (n = 1) were identified. Sixty KDa glycoprotein (gp60) gene amplicon sequencing of the C. parvum samples identified genotypes IIaA17G1R1 and IIaA15G2R1 for the first time from a dog. There were no significant associations between signalment data and Cryptosporidium status. While this was a study of one rehoming shelter, the presence of the potentially zoonotic C. parvum and C. canis in dogs highlights a public health concern. Further research is needed to better understand the epidemiology and potential impacts of Cryptosporidium infection in dogs.