Multi-centric histiocytosis: Experimental induction in broiler and specific pathogen-free leghorn chickens

Seventy-five 3-day-old broiler chicks and twenty specific pathogen-free leghorn chicks were injected with 0.5 ml of a homogenate, prepared from organs from broilers diagnosed with naturally-occurring multicentric histiocytosis (MH). Equal numbers of uninjected broiler and leghorn chicks (controls) were maintained in adjacent pens. Ten weeks later, nine broilers had well-developed gross and microscopic MH lesions. The distribution and histological appearance of lesions in these experimental chicks was similar to lesions described in naturally occurring field cases. Six leghorns had gross lesions similar to those found in their broiler counterparts; however, in the leghorns, the cellular masses contained more lymphocytes and, additionally, masses were found in the gizzard musculature. One gizzard contained a sarcoma. Broiler chickens with MH weighed less than their control counterparts and were more likely to be anaemic. Sequences specific for reticuloendotheliosis viruses (REV) were found in the MH homogen...