Background: Bovine anaplasmosis is a haemolytic disease of cattle caused by an obligate intra-erythrocytic bacterium Anaplasma marginale and is characterized by high fever, dyspnoea, anaemia, icterus, decreased milk production and death. The present study was undertaken to study the gross and histopathological changes caused by naturally occurring A. marginale infection in cattle. Methods: History and clinical examination of animals revealed inappetance/anorexia, presence of tick infestation, high fever, pale or icteric mucous membranes, tachycardia, dyspnoea and lymphadenomegaly. The diagnosis of A. marginale infection was done by blood smear examination and further confirmed by polymerase chain reaction and sequencing analysis. During the present study, two animals did not respond to treatment and were succumbed to A. marginale infection. A systematic post-mortem examination was performed on the animals and gross lesions were recorded. The tissue samples from various vital organs such as heart, lungs, liver, spleen and kidneys were collected in 10% neutral buffered formalin and processed for histopathological examination. Result: The post-mortem examination revealed emaciated carcass with yellowish discoloration of serosal surfaces of the abdominal organs, haemorrhagic heart, congestion of lungs, hepatomegaly, distension of the gallbladder and splenomegaly. The major histopathological changes noticed included myocardial degeneration and necrosis, interstitial pneumonic changes, degenerative changes in hepatocytes and renal tubular epithelial cells, enlargement of red pulp area of spleen with histiocytic proliferation and hemosiderosis. Histopathology also revealed inflammatory process characterized by infiltration of mononuclear cells in various organs. Very few reports are available on the pathological aspects of A. marginale infection and thus the outcome of the present study can yield valuable information to aid in the diagnosis of bovine anaplasmosis under field conditions.
Whole-Genome Sequencing of Mexican Strains of Anaplasma marginale: An Approach to the Causal Agent of Bovine Anaplasmosis
