Dolhin O. Canine trichuriasis (distribution, prevention and control measures)

The dissertation theoretically summarizes and experimentally solves the scientific problem regarding the distribution, laboratory diagnosis, control and prevention measures for canine trichuriasis in the territory of Poltava city, Ukraine. The average extensiveness and intensity of trichuriasis infestation in Poltava was 19.8 % and 78.7±8.60 eggs/g, respectively. The associative course of trichuriasis in dogs with helminthiasis and protozoa of the gastrointestinal tract has been clarified in detail. In 59.0 % of infested dogs trichuriasis occurs in the form of monoinvasion, in 41.0 % as mixed infection. Altogether six types of mixed infections were identified, where two-component associations were more often diagnosed (88.1 %). Three-component and four-component associations accounted for a smaller share (10.1 and 1.8 %, respectively). The most frequent co-members of Trichuris vulpis were the nematode Toxascaris leonina (48.6 %) and the protozoan Cystoisospora canis (41.3 %). Nematodes Toxocara canis (19.3 %) and cestodes Dipylidium caninum (4.6 %) were found rarer. Sandboxes and their adjacent areas in Poltava were highly contaminated with Trichuris nematode eggs: 61 out of 90 sandboxes contained Trichuris eggs with an average extensive contamination index of 67.78 % and an intensive contamination index of 195.79±18.41 eggs/kg. The territory of the Kyiv district of Poltava was the most contaminated with nematode eggs. There, 25 out of 30 sandboxes were contaminated with propagative stages of Trichuris development, and the level of parasite contamination was 83.33 % and 218.91±17.27 eggs/kg, respectively. The territory of Podilsky district was less contaminated with nematode eggs: 22 out of 30 sandboxes were contaminated with Trichuris eggs, and the level of parasite contamination was 73.33 % and 189.95±17.27 eggs/kg, respectively. The least contaminated was the territory of the Shevchenkiv district, where 14 out of 30 sandboxes were contaminated with Trichuris eggs, and the level of parasite contamination was 46.67 % and 163.70±21.04 eggs/kg. Peculiarities of age, seasonal dynamics and breed susceptibility to trichuriasis in dogs have been clarified. Dogs aged 6 to 12 months were most infested with Trichuris vulpis, the extensiveness and intensity of infestation were 31.2 % and 112.3±3.4 eggs/g, respectively. Half-breeds and non-breed animals were the most infected with causative agent of trichuriasis (EI – 42.2%, II – 106.7±9.4 eggs/g). Hunting dogs (EI – 20.7%, II – 95.8±9.1 eggs/g) and service and working dogs (EI – 19.6 %, II – 67.8±1.4 eggs/g) were somewhat less infested with Trichuris. The smallest rates of extensiveness and intensity of trichuriasis were found in dogs of decorative breeds (EI – 19.6%, II – 67.8±1.4 eggs/g). Among animals of hunting breeds, the most infested dogs were Labrador Retriever (EI – 25.2 %), Kurtzhaar (27.8 %) and Jagterrier (22.5 %). Among service and working dogs, the highest prevalence of trichuriasis was recorded in Rottweiler (EI – 41.4 %) and Belgian Shepherd (75.0 %). Pekingese (33.3 %) and toy terriers (38.9 %) were the most susceptible to the causative agent of trichuriasis among ornamental dogs. Seasonal dynamics of canine trichuriasis is characterized by the peak of infestation in summer (EI – 20.4 % and II – 103.86±4.72 eggs/g) and autumn (EI – 25.6 % and II – 105.72±4.13 eggs g). Declines in the indicators of the extensiveness and intensity of trichuriasis infestation were established in winter (EI – 10.1 % and II – 73.14±2.49 eggs/g) and spring (EI – 18.9 % and II – 93.05±3.41 eggs/g). It was established that in laboratory conditions, depending on temperature fluctuations (23 °C – 29 °C), the development period of Trichuris eggs to the invasive stage ranged from 15 to 27 days. At a temperature of 23 °C, 74.0 % of invasive T. vulpis eggs were formed in 27 days, and 26.0 % of eggs died during embryogenesis. At a temperature of 25 °C, the egg development to the invasive stage lasted 24 days, and 77.7 % of viable eggs were formed. At this temperature, 22.3 % of Trichuris eggs died. As the temperature rises, the egg development period gradually shortens to 18 days at a temperature of 27 °C, and 15 days at a temperature of 29 °C. In these conditions, formation of viable invasive eggs decreased and amounted to 81.0 and 64.3 %, respectively, and the percentage of egg death increased to 19.0 and 35.7 %. The timing of the formation of various stages of embryogenesis depended on the temperature, shortening as it rose.