Animals are mainly infested on pastures, and the first infection of young animals is usually caused by an invasion that has overwintered in ants. Dicrocelium eggs can already be found in their feces 2 months after the pasture of animals on pastures.
Animals become infected with dicroceliasis by swallowing ants containing encysted metacercariae along with grass. The period of development of dicrocelium in the body of sheep during experimental infection is 12 - 85 days. The duration of development of dicrocelia in cattle has not yet been established. Dicroceliosis, which has a large range of definitive and intermediate hosts, is distributed almost everywhere, but in the southern zones of the Soviet Union it is more common than in the northern ones. The intensity of infection can be very high and amount to several thousand copies.
Dicroceliosis. pathogenesis and pathoanatomical changes in dicroceliosis. In the earliest stages of the disease, changes are established only in the bile duct system. In them, phenomena of catarrhal and productive inflammation occur with a predominance of proliferative processes both from the side of the epithelium (papillomatous and glandular growths) and connective tissue. The connective tissue base of the ducts, both large and very small, thickens sharply. Changes in other organs, with the exception ofpancreas are not noted.
In cellular infiltrates, lymphocytes, plasma cells and transitional forms predominate. Macroscopic changes are manifested by diffuse lesions of small ducts in the marginal parts of the hepatic lobes. Large ducts look like evenly thickened strands. Diagnosis of dicroceliasis can be made by finding eggs in the feces of an animal suspected of casino dicroceliasis by sequential washing of faeces, etc. Dicroceliosis control of dicroceliasis in sheep and cattle. A full range of therapeutic and preventive measures cannot yet be recommended, since no therapy has been developed for dicroceliasis.