[Seasonal dynamics and the prevention of the meningoencephalitic form of listeriosis in lambs].

The seasonal dynamics of the meningoencephalitic form of listeriosis in lambs was followed up. The peak values in the disease course were found to be in the months of February and March. It is likely that outbreaks coincide with the start in feeding the lambs with roughage. The disease was bacteriologically and histologically shown to run its course primarily in lambs aged up to 6 months. Only in 3 cases the affected lambs were up to ten days of age. The changes in the central nervous system were characterized by leukocytic infiltration and diffuse glial proliferation (in 60.2 per cent of the cases), while in adult sheep predominated the focal glial proliferation. Liver and kidney cells showed necrobiotic changes. The use of the method of antibiotic prophylaxis led to recurrence of the disease, while immunizations with an inactivated vaccine against listeriosis suppressed further outbreaks.