Immunopathological Disorders in Swine and Equine

Immune system has evolved to protect the living body from the infections, which are themselves are evolving. The disorders of the immune system cause immunopathological diseases. Immunopathology is mainly characterized by the three responses in the body. These are increased response to an antigen, also known as hypersensitivity; decrease response to an antigen, also known as immunodeficiency; and response to self-antigen i.e., autoimmunity. Hemolytic anemia of newborn horse and piglets occurs because of immune-mediated destruction of the red blood cells of neonates by antibodies acquired from the dam in colostrum. Diagnosis of type II hypersensitivity is done by Coomb test and type IV hypersensitivity is mainly done by skin testing. Equine agammaglobulinemia is a primary immunodeficiency occurs due to B cell defect. Equine recurrent uvitis is one of the very common causes of vision loss in horses throughout the world. Autoantibodies are produced against the interphotoreceptor retinoid-binding protein and S-protein. The antibody produced against Leptospira interrogans cross reacts with the retinoid binding protein. Equine polyneuritis is the uncommon disease of the horses characterised by sacral and coccygeal nerve paralysis. Affected horses have circulating antibodies against peripheral myelin protein i.e., P2. Purpura hemorrhagica is an acute, non-contagious, aseptic necrotizing vasculitis, characterized by edema and petechial or ecchymotic hemorrhage of the mucosa and subcutaneous tissue. The M antigen of Streptococcus equi helps in the formation of immune complexes. Recurrent airway obstruction or heaves is a asthma like condition in mature horses following stabling and exposure to dusty hay and straw. Fungus like Aspergillus fumigatus, Faenia rectivirgula and Thermoactinomyces vulgaris are present in the hay or straw act as allergen.