THE EFFECT OF CONCURRENT INFECTIONS OF HEMORRHAGIC ENTERITIS VIRUS ORMARBLE SPLEEN DISEASE VIRUS AND EIMERIA-MELEAGRIMITIS IN TURKEYS

Turkey poults given the combination of marble spleen disease virus and Eimeria meleagrimitis (EM) exhibited a greater pathogenic effect caus ed by the virus and illustrated by an increased spleen weight:gain ind ex and antigen titre. Poults inoculated with both haemorrhagic enterit is virus (HEV) and EM exhibited an ameliorated pathogenic effect, in t hat the spleen weight:gain index and mean antigen titre were reduced. A reduction in the faecal score of the same birds was also noted when HEV was combined with EM. Poults receiving EM had lower numbers of cir culating heterophils and a higher number of lymphocytes compared to th e controls. These effects, however, were lost when either virus was si multaneously present with EM. Poults receiving both EM and HEV had the highest level of circulating monocytes.