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.

Distribution of Cryptosporidium species in sheep in the UK.

There have been few studies of the distribution of Cryptosporidium species and genotypes in sheep, and the anthropozoonotic potential has been questioned since one of the major human pathogens, Cryptosporidium parvum, is not always found. To investigate the situation in the UK we undertook three studies: a reactive sampling programme of flocks identified as exposures for human cases of cryptosporidiosis; investigation of neonatal cryptosporidiosis in lambs; and a screening programme of lambs at an open farm. C. parvum was the only species found in neonatal lambs with cryptosporidiosis and predominated in flocks sampled reactively to a human case of cryptosporidiosis. C. bovis was also found in the latter study but at a lower frequency than C. parvum. C. bovis and the cervine genotype were found in the orphan lambs under the screening programme. The results of these studies show that C. parvum is important in neonatal lamb diarrhoea and is widespread in sheep flocks in the UK, but that other Cryptosporidium species and genotypes are also present. Sheep, and young lambs in particular, must still be considered as a source of C. parvum infection for humans.

Microscopic and Molecular Tracing of Cryptosporidium Oocysts: Identifying a Possible Reservoir of Infection in Red Grouse.

Infection by Cryptosporidiumbaileyi causes respiratory cryptosporidiosis in red grouse Lagopuslagopusscotica. First diagnosed in 2010, it has since been detected across half of moors managed for grouse shooting in northern England. We hypothesised that contaminated grouse faeces within communal trays visited by grouse containing grit coated with flubendazole, provided to control Trichostrongylustenuis parasites of grouse, is a reservoir of infection. To establish the basis to this hypothesis, contents of 23 trays from a grouse moor were examined for Cryptosporidium oocysts. Contents were subjected to Immuno Magnetic Separation oocyst concentration techniques prior to examination by Immuno Fluorescence Antibody Test microscopy and molecular analysis on the 18S rRNA gene. Seven of 13 (54%) grit trays known to be used by infected grouse were positive for Cryptosporidium by IMS-IFAT, compared to two of 10 (20%) random background trays. Ten of the 13 (77%) trays used by infected birds amplified positive for Cryptosporidium by Polymerase Chain Reaction and three of the 10 (30%) random trays. All PCR amplified products sequenced matched with C.baileyi, with C.parvum also present in one tray. These data suggest that trays used to "worm" grouse may act as reservoirs of Cryptosporidium infection and their future design may need to be reconsidered to minimise contamination.