Comparison of two serotype 1 MDV isolates

We compared the RE1B and T. King (TK) serotype 1 isolates of Marek's diseas e virus (MDV) in vivo. Body and organ weights, mortality, and lesions indic ated that the TK inoculum established early infection more efficiently than RB1B and did greater damage to the bursa of Fabricius and thymus. Subseque nt studies showed that the TK inoculum that we used contained chicken infec tious anemia virus (CIAV). Therefore, pathogenicity profiles shown here sho uld be interpreted with the presence of CIAV contamination in the TK stock in mind.