Subgenotype analysis of Cryptosporidium isolates from humans, cattle, and zoo ruminants in Portugal

Abstract

Cryptosporidium parvum and Cryptosporidium hominis isolates from human immunodeficiency virus-infected patients, cattle, and wild ruminants were characterized by PCR and DNA sequencing analysis of the 60-kDa glycoprotein gene. Seven alleles were identified, three corresponding to C. hominis and four corresponding to C. parvum. One new allele was found (IId), and one (IIb) had only been found in Portugal. Isolates from cattle and wild ruminants clustered in two alleles. In contrast, human isolates clustered in seven alleles, showing extensive allelic diversity.

FIG. 1.

Amino acid sequence diversity among seven GP60 alleles of Cryptosporidium in humans and animals from Portugal. Sequences are labeled as alleles followed by sample identifications. Dots denote sequence identity to the allele IIa sequence in isolate BI.344, dashes denote nucleotide deletions, and ∼ indicates that sequence information was unavailable. IIa, IIb, IId, and Ic are C. parvum alleles, and Ib, Ie, and If are C. hominis alleles.

FIG. 2.

Distribution of GP60 alleles of C. parvum and C. hominis from humans, calves, and wild ruminants as revealed by a neighbor-joining analysis of nucleotide sequences. Isolates from calves are named BI, BM, IF, and B.fmv. Human isolates are named CH and CT; isolate CH.60 is from a sporadic case of a non-HIV-infected person.