Molecular characterization of Danish Cryptosporidium parvum isolates

Abstract

The genetic polymorphism among 271 Danish Cryptosporidium isolates of human and animal origin was studied by partial amplification and sequencing of the Cryptosporidium oocyst wall protein (COWP) gene, the 18S rDNA, and a microsatellite locus.The nucleotide sequence data reported in this paper are available in the GenBank database under the accession number AF469174. Furthermore, the microsatellite locus was studied directly using fragment analysis. A comparative analysis of DNA sequences showed the presence of 3 different subgenotypes (C1, C2 and C3) in C. parvum isolates from Danish cattle, with prevalences of 16.7, 17.2 and 73.1% including 13 (7.0%) mixed infections. Subgenotype C1 was significantly more prevalent (P<0.001) in the southern part of Denmark. In Cryptosporidium isolates of human origin the anthroponotic subgenotype H1 was identified, in addition to the zoonotic subgenotypes C1, C2, and C3. Of 44 human samples, 56.8% were anthroponotic, whereas 40.9% were zoonotic genotypes. One human isolate was characterized as C. meleagridis. The porcine Cryptosporidium isolates (N = 4) revealed a pattern which was genetically distinct from human and bovine isolates. Cryptosporidium in a hedgehog (Erinaceus europaeus L.) was identified for the first time. By microsatellite sequencing the hedgehog isolate showed a subgenotype distinct from the previously detected types. The assignment to subgenotype by microsatellite sequencing and fragment typing was 100% identical in samples where results were achieved by both methods. In addition, the fragment analysis proved more sensitive, easier, faster, and less expensive compared to sequencing.