Identification of Three Toxocara species, T. canis in Dogs, and T. cati and T. malaysiensis in cats, in Vietnam by PCR-RFLP Analysis and DNA Sequencing

Abstract

Toxocara canis and T. cati are common roundworms parasitizing dogs and cats, respectively. However, a recent study detected T. malaysiensis, but not T. cati, in cats from some parts of Ha Noi and Nam Dinh Provinces raising the question of whether T. cati is present in cats in Vietnam. This study was conducted to determine the composition of Toxocara species in dogs and cats in Vietnam. One hundred and twenty-seven Toxocara adult worms were collected from dogs and cats and were analyzed by PCR-RFLP assay and DNA sequencing of a partial section of the cox1 gene. As a result, all samples amplified by PCR showed bands about 430 bp in length. PCR products digested by MseI from isolates from cats and dogs showed four and two restriction patterns, respectively. The six different patterns were chosen to sequence. Based on the restriction patterns and sequencing results, two Toxocara species were identified in the cats, namely T. cati (110/111 isolates) and T. malaysiensis (1/111 isolates) collected from Ha Noi and Hai Duong, respectively; and T. canis was identified in the dogs (16/16 isolates). In addition, the present study indicated intra-specific sequence variations of Toxocara spp. in dogs and cats. In conclusion, the study confirmed the presence of both T. cati and T. malaysiensis in cats, and T. canis in dogs in Vietnam, and suggests further large-scale investigations to fully understand the distribution and genetic variations of Toxocara spp. in cats and dogs in Vietnam.