The effects of seasonality and group size on fecal egg counts in wild Przewalski’s horses (Equus ferus przewalskii, Poljakov, 1881) in the Chernobyl Exclusion Zone, Ukraine during 2014 – 2018

The aim of this study was to investigate the difference in Fecal Egg Counts (FEC) with regard to group size, age, sex and body condition of wild free-roaming Przewalski’s horses in the Chernobyl Exclusion Zone (Ukraine), across different seasons, over a five-year period (2014 – 2018). We hypothesized that horses from larger group sizes would have higher faecal egg counts (FECs). The relationship between FECs and the year and season of sample collection, and age, sex and group size of the horses was analyzed. Generalized linear model using positive strongylid FEC`s as a variable response, was used to investigate the differences in FECs between the groups.

Nematode (Strondylidae, Parascaris spp., Habronematidae) and cestode (Anoplocephalidae) eggs were also identified. Stronglyids were the most prevalent helminth egg, and had the highest FECs.

The model for egg counts of strongylids showed that season and group size of horses were statistically significant. Presence of strongylid eggs was not dependent on age and sex of horses. We suggest that this could be a result of parasite transmission between individuals and groups in places were animals aggregate around water sources or collective farms.

Results obtained in this current study broaden the knowledge of gastrointestinal parasites in free-roaming horses under wild natural conditions.