This inflammation is nonsuppurative, with massive accumulations of mononuclear cells in a perivascular location, as well as throughout the involved parenchyma, where necrosis is extensive. Although the initial action of the virus is to cause a primary demyelination, this phase is rapidly followed by an extensive inflammatory response that is considered to be a cell-mediated immunopathologic response. The caudal brainstem is occasionally affected but rarely the prosencephalon. Lesions can be focal, multifocal, or diffuse in the CNS, with the spinal cord most commonly affected. The neurologic disease usually occurs between 1 and 6 months of age, is acute in onset, and is rapidly progressive. The virus is transmitted not only from an infected doe to her kid in the colostrum and milk, but also by direct contact transmission. 17–21, 77 In addition to causing a demyelinating leukoencephalitis of young goats, this virus causes pneumonitis, arthritis, and mastitis of older adult goats.
Secondary bacterial bronchopneumonia is common in affected animals.Īlexander de Lahunta DVM, PhD, DACVIM, DACVP, Eric Glass MS, DVM, DACVIM (Neurology), in Veterinary Neuroanatomy and Clinical Neurology (Third Edition), 2009 CAPRINE ARTHRITIS ENCEPHALITIS VIRUSĬaprine arthritis encephalitis (CAE) is a multisystem viral disease of goats caused by a lentivirus, a type-C retrovirus that is related to the visna virus of sheep. The encephalitic or arthritic signs tend to obscure the respiratory signs, which are only evident on exertion. The pulmonary form of CAE can be mistaken for parasitic pneumonia ( Muellerius capillaris) because these two diseases have lymphocytic interstitial pneumonia and can coexist in the same goat.Ĭlinically, goats are active and afebrile but progressively lose weight despite normal appetite. One important difference between the pneumonias of CAE and maedi is that in CAE the alveoli are filled with proteinaceous eosinophilic material (alveolar proteinosis), which in electron micrographs has structural features of pulmonary surfactant. Microscopically, the alveolar walls are thickened by lymphocytes and conspicuous hyperplasia of type II pneumonocytes ( Fig. The tracheobronchial lymph nodes are consistently enlarged. The lungs are gray-pink and firm in texture with numerous, 1- to 2-mm, gray-white foci on the cut surface.
Grossly, the interstitial pneumonia is diffuse and tends to be most severe in the caudal lobes. It can take several months before serum antibodies can be detected in infected goats. Like maedi, there is some evidence that the recruitment of lymphocytic cells results from dysregulation of cytokine production by infected macrophages and lymphocytes in affected tissues. Infected macrophages are disseminated hematogenously to the central nervous system, joints, lungs, and mammary glands. After coming into contact with mucosal cells at the portal of entry, the virus is phagocytized by macrophages, which migrate to the regional lymph nodes. Horizontal transmission between infected and susceptible goats via the respiratory route has also been described. Similar to maedi, CAE infection presumably occurs during the first weeks of life when the doe transmits the virus to her offspring through infected colostrum or milk. The lentivirus of CAE, caprine arthritis and encephalitis virus (CAEV), is closely related to visna/maedi virus and, in fact, cross infection with CAE virus in sheep has been achieved experimentally. In addition, infection with CAE virus can cause chronic lymphocytic interstitial pneumonia. This disease has two major clinicopathologic forms: One involves the central nervous system of goat kids and young goats and is characterized by a nonsuppurative leukoencephalomyelitis the other form involves the joints of adult goats and is characterized by a chronic, nonsuppurative arthritis-synovitis. It was first described in the United States in the 1970s, but it also occurs in Canada, Europe, Australia, and probably elsewhere. Martinson, in Pathologic Basis of Veterinary Disease (Sixth Edition), 2017 Caprine Arthritis-Encephalitis.Ĭaprine arthritis-encephalitis (CAE) is a retroviral disease of goats (small ruminant lentivirus) that has a pathogenesis remarkably similar to that of visna/maedi in sheep.
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