Helminth fauna of sympatric Przewalski’s Equus przewalskii Poljakov, 1881 and domestic horses E. caballus L. in the Chernobyl exclusion zone, Ukraine

In 1998 Przewalski’s horses have been introduced in the Chernobyl exclusion zone (CEZ), N Ukraine. They live in the zone under natural conditions. No anthelminthic treatment to these introduced horses has been applied to date. In this same area, 19 domestic horses were also stabled by some peasants. Eighteen years after the Chernobyl nuclear disaster, and five years after this introduction, the diagnostic dehelminthisation method has been applied both to the Przewalski’s horses (n = 21) and the domestic horses (n = 6). In addition, in one Przewalski’s and one domestic horse helmith fauna was surveyed using the post-mortem method. A total of 29 and 19 helminth species has been recorded in the Przewalski’s and domestic horses respectively. Only six helminth species were common for the two horse species compared. Species from the family Strongylidae constituted the dominant helminth group. Four cyathostomine species (Cyathostomum catinatum; Cylicostephanus minutus, C. longibursatus, Cylicocyclus nassatus) formed the majority of helminth parasites both in the Przewalski’s and domestic horses. Our findings suggest that the CEZ has no effect on the species diversity of helminth fauna parasiting Przewalski’s horses, neither it has an effect on the prevalence and intensity of parasite infestation. Behavioural and ecological studies also support the lack of such effect.