Contamination of the environment by strongylid (Nematoda: Strongylidae) infective larvae at horse farms of various types in Ukraine.

Analysis of the influence of horse-keeping conditions by contamination of the environment (pastures, paddocks, and stalls) by the strongylid infective larvae (L(3)) was carried out at various types of horse farms, hippodromes, and riding clubs in Ukraine. A total of 1,237 horses from three types of horse-keeping conditions were examined. Epidemiological studies of stall and grazing area (pasture and paddocks) contamination by L(3) were performed at hippodrome (stalled horse-keeping) and horse farms with stall/paddock-keeping and stall/pasture-keeping conditions. Grass and stall litter samples were examined by the Baermann procedure. It was found that horses of stall-keeping conditions had the lowest level of strongylid infection (prevalence 46.4-77.8%, average infection 25.6-92.9 eggs per gram of feces (EPG)) and lowest proportion of large strongyle L(3) in coprocultures (1.6-11.3%). Horses of stall/pasture-keeping conditions were the most infected (prevalence 95.1-100%, average infection 198.2-453.7 EPG), and the proportion of large strongyle L(3) was 17.3-24.7%. Strongyle L(3) were found in litter of all parts of individual stalls; areas at the stall center, "toilet", and entrance were the most contaminated. The highest L(3) number in stall litter was registered in summer. Contamination of permanent pasture grass by L(3) was notably lower than grass in paddocks (86.3-161.4 L(3)/kg compared with 305.9-409.1 L(3)/kg). The highest level of pasture grass contamination was observed in the middle of summer (July)--up 970.7 L(3)/kg. The results obtained confirmed importance of environmental contamination in epidemiology of horse strongylidosis at various types of horse-keeping conditions.