Desordens hemostáticas em ovinos parasitados por Haemonchus contortus

Abstract

Hemonchosis remains, to this day, the main disease found in sheep farming around the world. It is characterized by the parasitemia of sheep by the hematophagous agent Haemonchus contortus. The parasite causes damage to the gastrointestinal tract of infected animals. These lesions, together with the secretion of anticoagulant factors and proteins, facilitate the parasite's feeding through the bleeding induced in these locations. Blood loss generated by the parasite leads to anemia and excessive loss of proteins such as albumin, resulting in clinical symptoms of weight loss, increased morbidity and reduced production efficiency, which causes significant economic losses to the industry and affects well-being. affected animals. This study aims to highlight and point out the hemostatic changes that Haemonchus contortus infection causes in sheep. 19 sheep of both sexes and ages ranging between 7 and 8 months were used, which experimentally received 10.000 infective strongyloid larvae. After 30 days, the animals were subjected to hemostatic tests to evaluate possible changes in the coagulation cascade generated by parasites. The results showed a statistically significant difference (p < 0.05) between experimentally parasitized sheep and parasite-free sheep for all diagnostic tests, which included: Activated Coagulation Time (p = 0.0001), Activated Partial Thromboplastin Time (p = 0.0045) and Prothrombin Time (p = 0.0325), using ANOVA as a comparative test. Furthermore, significant differences (p < 0.05) were observed in hematocrit (p < 0.0001) and platelet count (p < 0.0001) values. Infection by gastrointestinal parasites brings hemostatic changes related to the intrinsic pathway, which are harmful to sheep production and the well-being of affected animals.