Location: Animal Disease ResearchTitle: Chapter 60: Visna-maedi
|MURPHY, BRIAN - University Of California, Davis|
|KNOWLES, DONALD - Washington State University|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/17/2018
Publication Date: 10/1/2018
Citation: Murphy, B., Knowles, D., Highland, M.A. 2018. Visna-maedi. In: Coetzer, J.A.W., Thomson, G.R., Maclachlan, N.J., Penrith, M.L., editors. Anipedia-Infectious Diseases of Livestock. Anipedia. Available: https://www.anipedia.org/resources/visna-maedi/1035.
Interpretive Summary: This is an informational chapter on Visna meadi, a viral disease of sheep, written for Infectious Diseases of Livestock by ANIPEDIA. This chapter provides current/updated information on this virus and the disease entities that it causes. This chapter describes aetiology,epidemiology,pathogenesis,clinical signs, pathology,diagnosis,differential diagnosis,and control of infection.
Technical Abstract: Visna-maedi, one of the so-called slow viral diseases of sheep, is caused by a non-oncogenic retrovirus of the Lentivirus genus. The Icelandic name denotes the two most common forms of the disease, maedi referring to the respiratory form of the disease (“breathlessness”, chronic interstitial pneumonia) and visna referring to the neurologic form of the disease (“wasting”, demyelinating leukoencephalomyelitis). Two other disease syndromes, arthritis and chronic mastitis, are more rarely seen. The disease is also known as ovine progressive pneumonia or Montana sheep disease in the USA, ovine lentivirus, zwoegersiekte in the Netherlands, la bouhite in France, and Graaff-Reinet disease in South Africa. It was first described in 1915 in South Africa by Mitchell, who regarded the condition as an aberrant form of jaagsiekte disease, followed by reports of disease in the state of Montana (USA). The confusion with pulmonary adenomatosis (jaagsiekte) caused by Mitchell’s report was resolved by De Kock, who was the first to realize that they were two distinct diseases, often coexisting in the same animal. The chronic pneumonia, named Graaff-Reinet disease after the town in which the experimental station was located, and where the diseased animals were located. In Iceland, the introduction of visna-maedi virus (VMV) was traced to the importation in 1933 of Karakul rams from Germany, one of which carried both visna-maedi and jaagsiekte viruses. Sigurdson and collaborators first isolated VMV in 1960. Most of the early work on visna-maedi was done in Iceland, where it was initially considered to be two separate diseases. This is an informational chapter on Visna maedi, written for Infectious Diseases of Livestock by ANIPEDIA. This chapter provides current/updated information on this virus and the disease entities that it causes. The chapter describes the aetiology, epidemiology, pathogenesis, clinical signs, pathology, diagnosis, differential diagnosis, and control of infection. The chapter also provides a long list of relevant references.