Investigations into the pH stability of bluetongue virus and its survival in mutton and beef

Abstract

Experiments are reported in which the in vitro pH stability of bluetongue virus as well as the survival of this virus in muscle of mutton and beef carcasses, have been investigated. (a) A marked loss of infectivity occurred between pH 6·1 and pH 6·3 under laboratory conditions when bluetongue virus was subjected to those hydrogen ion concentrations normally encountered in carcass meat. (b) The survival of bluetongue virus in carcass meat appears to be dependent upon the post-mortal pH changes. The virus was shown to persist for a period of 30 days at 4⁰C in an ovine carcass, where the pH failed to drop below pH 6·3. On the other hand, meat with a pH in the region of 5·4, did not contain infective virus. (c) A bovine carcass was shown to contain infective bluetongue virus on the tenth day after artificial infection, although no clinical signs of disease were encountered. (d) There appeared to be a greater tendency for bluetongue virus to be present in the M. gluteus than in the M. longissimus dorsi.