found: Fields virology:p. 162 (visna virus, a nononcogenic retrovirus, produces a chronic infection in sheep (Visna) that also behaves like a slow virus disease)
found: Dulbecco virology:p. 377 (visna-maedi virus which causes encephalitis (visna) or pneumonia (maedi) in sheep)
found: Maedi-visna and related diseases, 1990:p. 6 (now maedi and visna are known to be two different manifestations of an infection with the same virus and are therefore referred to as maedi-visna disease ... maedi-visna virus)
found: MESH(Visna-maedi virus)
notfound: Web. 3