Zoonotic linkage and variation in Cryptosporidium parvum from patients in the United Kingdom.

Relationships between patient exposure risks and variation within the Cryptosporidium parvum 60 kDa glycoprotein (GP60) gene were explored in samples isolated from human cases of cryptosporidiosis (n=69) in England and Wales. GP60 family IIa predominated (n=56), followed by IId (n=9). One case was IIc, a newly named genotype IIcA5G3j, and isolates from three cases did not amplify with the GP60 primers. Cases with GP60 family IIa were more likely than IId to have visited a farm, or had contact with farm animals or with their faeces in the 2 weeks prior to illness. Within GP60 family IIa, genotypes IIaA15G2R1 and IIaA17G1R1 predominated (22 cases each); nine other IIa genotypes accounted for 12 cases. The IId genotypes were mainly IIdA17G1 and IIdA18G1 (3 each). Cases with IIaA17G1R1 were particularly linked to zoonotic exposures: visiting a farm or having farm animal contact in the 2 weeks prior to illness. These findings provide further evidence of zoonotic pathways for the transmission of C. parvum isolates.