Parameters of the blood and immune system of Rutilus rutilus lacustris (Cypriniformes: Cyprinidae) during an invasion with pleurocercoids of Ligula intestinalis (Pseudophyllidae: Ligulidae)

The morphological composition of blood and the reaction of the immune system in a Siberian roach Rutilus rutilus lacustris (Baikal, Chivyrkuiskii Bay) both infested and not infested with pleurocercoids of Ligula intestinalis is investigated. An infestation with L. intestinalis renders a negative effect on the morphological and immunological parameters of blood supporting the immunological homeostasis of its host. In comparison with individuals not infested, the following changes are recorded in the infested individuals: a decrease in the count of erythrocytes and leukocytes (due to a decrease in lymphocytes), increase of the quantity of foam cells, inhibition of T- lymphocytic link of immunity, and a decrease in the content of the total protein, albumin, and gamma-globulin fractions of protein. The change of hematological and immune reactions of a host organism ensures a prolonged mutual adaptation of the parasite and host.