Toxascaris Leonina in Dogs – A Nematode Species of Little Interest But High Prevalence in Some Regions  : [Preprint]

The aim of this study was to examine free-roaming dogs from the city of Astana and its suburbs to obtain information on the occurrence of Toxascaris (Ts.) leonina and other intestinal parasites. Faecal samples from 500 free-roaming dogs from the city of Astana and its suburbs were collected within 1–2 days of admission to the municipal animal shelter during three time periods (May to October 2019, September 2020, and April 2021). Samples were examined macroscopically followed by the qualitative Fuelleborn flotation method; nematode egg-positive samples were then subjected to a modified McMaster method to determine the number of eggs per gram of faeces (EPG). In total, 66.0% of all dogs examined were shedding faecal stages of at least one parasite species. Ts. leonina eggs were the most common (53.8%), followed by Toxocara spp. eggs (14.8%), taeniid eggs or Taenia proglottids (4.8%), Cystoisospora canis oocysts (2.6%), and Dipylidium egg capsules or proglottids (2.0%); hookworm and whipworm eggs were found only once each. The prevalence of Ts. leonina egg shedding was significantly associated with age class but not with sex: dogs aged between 6 months and 2 years were more likely to be Ts. leonina egg positive than puppies. The intensity of Ts. leonina egg shedding was also age dependent: dogs aged between 6 months and 2 years had significantly higher EPGs compared to younger or older animals. In contrast, the prevalence of Toxocara spp. egg shedding was associated with both age class and sex: dogs older than 2 years were less likely to shed Toxocara spp. eggs than puppies, and females were less likely to be Toxocara spp. egg positive compared to males.