A Large Survey of Croatian Wild Mammals for Giardia duodenalis Reveals a Low Prevalence and Limited Zoonotic Potential

Abstract

Wild mammals are considered an important source of potentially zoonotic Giardia duodenalis parasites, yet surprisingly little information is available on the actual prevalence and the genetic identity of the species they harbor. A large survey was conducted in Croatia by collecting 832 fecal samples from red deer (Cervus elaphus, n = 374), roe deer (Capreolus capreolus, n = 21), wild boars (Sus scrofa, n = 144), foxes (Vulpes vulpes, n = 66), bears (Ursus arctos, n = 19), wolves (Canis lupus, n = 127), jackals (Canis aureus, n = 8), and hares (Lepus europeus, n = 73). Fecal samples were tested for the presence of Giardia cysts using fluorescent microscopy. The observed prevalence ranged from low (1% in red deer, 1.7% in wild boars, and 4.5% in foxes) to moderate (10% in wolves and 12.5% in jackals) to high (24% in roe deer). No cysts were observed in bears and hares. Polymerase chain reaction was performed on microscopically positive samples to amplify fragments of the small subunit ribosomal gene, the ribosomal 5.8S gene and the two flanking internal transcribed sequences, and the triose phosphate isomerase gene. Sequence analysis showed a predominance of G. duodenalis assemblage A in both ruminants (genotypes A1 and A3) and carnivores (genotype A1). G. duodenalis assemblages B, C, and D, as well as Giardia microti, were also detected in this study. This is the first molecular description of the parasite from the red deer, the wolf, and the jackal. The data point to a minor role of wild mammals as reservoirs of zoonotic assemblages of G. duodenalis, albeit cycling between sylvatic and domestic animals is possible.

Prevalence and molecular typing of Giardia duodenalis in wildlife from eastern Poland

“…The overall prevalence in wild boars was 41%, which is higher than values (0-1.7%) reported in other studies (Paziewska et al 2007, Beck et al 2011, Castro-Hermida et al 2011. We identified assemblage B in wild boars for the first time.…”

“…Epidemiological studies in Poland have shown a similar prevalence (Paziewska et al 2007, Solarczyk 2009). Worldwide, the prevalence among wild cervids ranges between 1 and 24%, with no obvious correlation with the different deer species examined (Rickard et al 1999, Beck et al 2011. So far, only assemblage A has been found among cervid species; therefore this study is the first to report the presence of assemblage B in these hosts.…”

“…We identified assemblage B in wild boars for the first time. While this assemblage has been detected in swine (Farzan et al 2011), only assemblage A was identified in a wild boar from Croatia (Beck et al 2011).…”

Endoparasites of wildcats in Croatia

“…cysts by feeding on rodents. rodents carry Giardia muris, Giardia microti, or Giardia duodenalis assemblage G, which may be unable to establish infection in wildcats, as was described for foxes (BECK et al, 2011a). Still, the true origin of Giardia sp.…”

“…Infection with Giardia sp. in wild carnivores in Croatia, other than wildcats, was described by BECK et al (2011a) and ranged from 4.5% in foxes, 10% in wolves, and up to 12.5% in jackals. also, there is a report of Giardia sp.…”