TICK-BORNE FEVER IN LAMBS OF DIFFERENT AGES

Four groups of lambs aged 1 week, -4 weeks, 1/2 year and 1 year old re spectively were inoculated with Ehrlichia phagocytophila infected bloo d. Clinical signs, temperature reactions, haematological changes and p arasitaemia were more moderate in lambs inoculated with E. phagocytoph ila at the age of 1 week than those recorded in the older animals. The clinical response to tick-borne fever (TBF) appears to be more severe with increasing age of the lambs. The lymphocyte reactivity to mitoge ns was reduced in the TBF infected lambs, and was most pronounced in l ambs in the 3 older age groups.