Genotyping of Giardia intestinalis from domestic and wild animals in Japan using glutamete dehydrogenase gene sequencing

Abstract

To determine the genotypes of Giardia intestinalis from domestic and wild animals in Japan, Giardia isolates obtained from feces of 24 dogs kept in households and breeding kennels, three companion cats, five dairy calves and three wild monkeys, Macaca fuscata, were genotyped using the 177 bp sequence of the glutamete dehydrogenase gene (gdh). The genotypes were assemblages A, C, D or A/D for dog isolates, Assemblage F for cat isolates, assemblages A or E for calf isolates and assemblage B for monkey isolates. This is the first report on the genotypes of Giardia isolates from cats, calves and wild monkeys in Japan.

Introduction

Giardia intestinalis (syn. G. duodenalis, G. lamblia) is the most common intestinal parasite of humans as well as of domestic and wild animals. Although G. intestinalis isolates from different host species are morphologically indistinguishable from each other, they have been grouped into genotypes on the basis of molecular characteristics. Giardia isolates from humans have exclusively shown one of two major genotypes referred as to assemblages A and B (Mayrhofer et al., 1995, Monis et al., 1996), which coincide with the formerly used terms Polish and Belgian in Europe (Homan et al., 1992) and groups 1–3 in North America (Nash, 1995), respectively. Assemblages A and B have also been found in isolates from domestic and wild animals, such as dogs, cats, cattle, pigs, slow loris, siamang, beavers, white-tailed deer and so on, suggesting that these assemblages have zoonotic potential. On the other hand, Giardia isolates from animals revealed some genotypes that differed from assemblages A and B. Assemblages C and D in dogs isolates, assemblage E in cattle isolates and assemblages F and G in cat and rat isolates, respectively (Monis et al., 1996, Monis et al., 1999). These animal-derived genotypes seem to be each host-specific and non-zoonotic (Thompson, 2000).

In Japan, Giardia infection has been found in 14.6–22.9% of dogs kept in households and breeding kennels (Itoh et al., 2001, Itoh et al., 2004) and 31.2% of companion cats (our unpublished data). Further, Giardia infection has also been found in 26.7% of wild monkeys, Macaca fuscata, in Shimokita Peninsula, and in 13.8% in wild serows, Capricornis crispus, in the north part of Japan (our unpublished data). There is only one report on the genotype of Giardia isolated from four dogs (Abe et al., 2003), though genotyping is of importance in view of public health for the above-mentioned reasons. In the present study, we clarified the genotypes of G. intestinalis isolated from domestic dogs and cats, dairy calves and wild monkeys in Japan using glutamete dehydrogenase (gdh) gene sequencing.