Background: Contact between wild (saiga) and domestic (sheep) animals on pastures result in a composite community of helminths. Wild animals like saigas are vulnerable to parasites and the diseases they transmit are fatal. Adults may be less susceptible to infection than their offspring, but remain a dangerous source of parasite spread. Aim: The aim of the article is to determine the environmental factors influencing the spread of helminthiasis (echinococcosis, coenurosis, and moniziosis) in animals. Methods: Epizootological indicators of the saigas helminth fauna have been studied to assess the epizootic state of the area, and the causes of invasive foci appearance (caenurosis, moniziosis, and echinococcosis) in farms in the Kaztalov and Zhanybekov districts of Western Kazakhstan region. The diagnosis of saiga helminth infections was confirmed by well-grounded helminthological and pathological anatomical examinations of dead saigas. Results: Climatic, natural and anthropogenic factors of the seasonality of infestation are considered. The climatic factors of helminth infestation in animals were described, based on the influence of environmental factors, which include favourable conditions for the survival of helminth larvae. The main source of helminth infestation is the animals' watering places; therefore, it is necessary to green and create a large number of watering places, which will reduce the disease rate and improve the health of the animals from infestation. Conclusion: Regular helminthological and ecological monitoring in animal populations is necessary to ensure and preserve natural biocenoses.