Response to Eimeria tenella Infection Among Lines of Fowl Selected for Differential Resistance to Avian Leukosis , ,

THE suggestion of a direct association between coccidiosis and avian leukosis remains controversial. A number of circumstances could result in an apparent association between the two diseases. Those conditions which permit introduction and proliferation of one of the infective agents (leukosis virus or coccidia) would probably be favorable for the introduction of the other. Biggs et al. (1968) concluded that infection with Marek’s disease virus may increase the susceptibility of chickens to coccidial infection. This phenomenon may be partially attributed to the impaired immunological capacity of chickens infected with Marek’s disease which has been demonstrated by Purchase et al. (1968). Edgar et al. (1968) reported evidence of a loss of acquired resistance to coccidiosis at an early age among birds developing lymphoid leukosis or Marek’s disease. On the other hand, damage to the intestinal wall caused by coccidia could provide an easy route of entry for leukosis virus. The possibility…