Unusual Cryptosporidium species recovered from human faeces:: first description of Cryptosporidium felis and Cryptosporidium 'dog type' from patients in England

DNA was extracted from faecal samples collected from 1680 patients in which Cryptosporidium oocysts were recognised by light microscopy. DNA from faeces from five of these patients failed to amplify by PCR three gene fragments - the Cryptosporidium oocyst wall protein (COWP) gene, the thrombospondin-related adhesive protein of Cryptosporidium-1 (TRAP-C1) gene and the thrombospondin-related adhesive protein of Cryptosporidium-2 (TRAP-C2) gene - with primers designed from C, parvum sequences. However, DNA from these five patients did amplify cryptosporidial 185 rDNA gene fragments and a heat-shock protein (HSP70) gene fragment was also amplified from four of them. The purpose of this study was to characterise further the Cryptosporidium associated with infection in these patients. DNA sequence analysis of 18S rDNA genes showed that four of these patients were infected by C, felis, and the remaining one by an as yet un-named Cryptosporidium. species designated the 'dog type' (C, dt), Infection by C, felis was further confirmed in ail four patients by DNA sequence analysis of the HSP70 gene. Oocysts present in all five samples reacted strongly with two anti-cryptosporidial oocyst monoclonal antibodies, except for the C,dt, which was tested with only one of the antibodies. Two of the patients infected by C. felis had underlying illness; one 8-year-old male had an undefined severe inherited underlying condition, and the second patient, a 32-year-old male, was HIV positive. Two of the remaining three patients (two females aged 1 and 2 years, respectively) were apparently immunocompetent tone infected with C. felis and one with the C,dt), No information was obtained for the fifth patient. The patient infected by C. dt had a recent history of travel to Africa. This is the first report of infection with these two Cryptosporidium species in immunocompetent patients, and in any patient in the UK.