W. Homan et al., Characterization of Cryptosporidium parvum in human and animal feces by single-tube nested polymerase chain reaction and restriction analysis, PARASIT RES, 85(8-9), 1999, pp. 707-712
A DNA isolation and purification method is described that produced DNA free
of inhibitory substances in 148 of the 159 analyzed fecal samples. The pol
ymerase chain reaction (PCR) product from a sensitive single-tube nested PC
R that amplifies a part of an oocyst protein was used to characterize Crypt
osporidium parvum genotypes by a simple restriction analysis. Genotype 1 wa
s solely detected in human-derived oocysts, genotype 2 was present in both
animal and human-derived oocysts. The ratio between both genotypes in human
s in The Netherlands varied markedly between samples obtained during a peri
od of augmented cases of cryptosporidiosis in the western part of the count
ry and randomly selected samples from gastroenteritis patients. Sequence an
alysis of a 581-bp fragment from the nested PCR product revealed 12 nucleot
ide substitutions between the two genotypes. Sequences from isolates in eac
h genotype group were identical.