Diversity of Hepatozoon species in wild mammals and ticks in Europe

Background Hepatozoon spp. are tick-borne parasites causing subclinical to clinical disease in wild and domestic animals. Aim of this study was to determine Hepatozoon prevalence and species distribution among wild mammals and ticks in Europe. Methods Samples of wild mammals and ticks, originating from Austria, Bosnia and Herzegovina, Croatia, Belgium and the Netherlands, were tested with PCR to amplify a similar to 670-bp fragment of the small subunit ribosomal RNA gene. Results Of the 2801 mammal samples that were used for this study, 370 (13.2%) tested positive. Hepatozooncanis was detected in samples of 178 animals (3 Artiodactyla, 173 Carnivora, 1 Eulipotyphia, 1 Lagomorpha), H.martis in 125 (3 Artiodactyla, 122 Carnivora), H.sciuri in 13 (all Rodentia), Hepatozoon sp. in 47 (among which Hepatozoon sp. Vole isolate, all Rodentia) and H.ayorgbor in 4 (all Rodentia). Regarding origin, 2.9% (6/208) tested positive from Austria, 2.8% (1/36) from Bosnia and Herzegovina, 14.6% (173/1186) from Croatia and 13.9% (190/1371) from Belgium/the Netherlands. Of the 754 ticks collected, 0.0% (0/35) Hyalomma sp., 16.0% (4/25) Dermacentor spp., 0.0% (0/23) Haemaphysalis spp., 5.3% (24/50) Ixodes and 1.4% (3/221) Rhipicephalus spp. tested positive for Hepatozoon (4.2%; 32/754), most often H.canis (n = 22). Conclusions Hepatozooncanis is most present in mammals (especially in Carnivora such as gray wolves and golden jackals) and ticks, followed by H.martis, which was found merely in stone martens and pine martens. None of the rodent-associated Hepatozoon spp. were detected in the ticks, suggesting the possible implication of other arthropod species or non-vectorial routes in the transmission cycle of the hemoprotozoans in rodents. Our findings of H.canis in ticks other than R.sanguineus add to the observation that other ticks are also involved in the life cycle of Hepatozoon. Now that presence of Hepatozoon has been demonstrated in red foxes, gray wolves, mustelids and rodents from the Netherlands and/or Belgium, veterinary clinicians should be aware of the possibility of spill-over to domestic animals, such as dogs.

Automated summary

The goal of this study was to determine the prevalence and distribution of Hepatozoon parasites in wild mammals and ticks in Europe. The results showed that out of the 2801 mammal samples tested, 370 (13.2%) were positive. Hepatozoon canis was the most common species detected, primarily infecting carnivores such as dogs. These findings are important for monitoring and controlling the spread of these parasites and protecting the health of domestic animals.