A FIELD-STUDY OF OVINE BACTERIAL MENINGOENCEPHALITIS

Bacterial meningoencephalitis most commonly affected lambs two to four weeks old (median three weeks, range three days to six months) with c linical signs of episcleral congestion, lack of suck reflex, weakness, altered gait and depression extending to stupor, but hyperaesthesia t o auditory and tactile stimuli. Opisthotonos was observed during the a gonal stages of the disease. Analysis of lumbosacral cerebrospinal flu id revealed a highly significant increase in protein concentration (P< 0.01) with a neutrophilic pleocytosis, but bacteriological culture yie lded organisms in only a few cases. A response was achieved with high doses of dexamethasone and chloramphenicol in only one of 20 cases. Po lyarthritis and liver abscesses in a number of lambs provided evidence of a previous bacteraemic or septicaemic episode but no definite sour ce of the central nervous system infection was identified. In common w ith other infectious bacterial conditions which are prevalent during t he early life of sheep, control measures should ensure an adequate tra nsfer of passive antibody, repeated treatments of the navel, and hygie nic conditions is the lambing and rearing environments.