Molecular epidemiological investigation of unicellular parasites of companion animals

Abstract

Since the number of pet animals has increased worldwide in the last decades, and the diagnostic tools in veterinary parasitology also developed – ensuring access to more information on parasites –, the aim of the present study was to reveal the presence of different protozoa of various companion animals, and to examine their genetic diversity depending on the possible ways of their transmission. Therefore, altogether 1039 samples were collected from companion animals and examined for the presence of unicellular parasites with traditional parasitological methods and molecular biological methods including phylogenetic analysis. First, 164 samples were collected from five rodent species and rabbits in five locations in Hungary, to examine the presence of G. duodenalis. Parasitological analysis revealed the presence of cysts in 58.3% of asymptomatic Norway rats and 27.6% of chinchillas. Three degus were also found Giardia-infected (prevalence: 16.7%) using flotation technique. With PCR targeting three genetic markers, 3.2% of the samples showed positivity, whereas a rate of 21.9% prevalence was detected with flotation. The PCR products of five samples could be DNA sequenced. Phylogenetic analysis based on the partial sequences of the beta-giardin gene revealed the presence of assemblages B and G in rats. In addition, assemblage E was detected in a beaver, while assemblage B was present in a chinchilla. The results show that synanthropic rodent species have different epidemiological roles in the study region, depending on the prevalence of shedding Giardia cysts or harboring zoonotic variants of G. duodenalis. Moreover, our findings confirm that pet rodents may pose a risk for zoonotic Giardia-transmission.