Synergy of subgroup J avian leukosis virus and Eimeria tenella to increase pathogenesis in specific pathogen free chickens.
To investigate the effects of co infections of subgroup J avian leukosis virus (ALV J) and Eimeria tenella on the pathogenesis in specific pathogen free (SPF) white leghorn chickens, groups of chickens were infected with ALV J strain NX0101 at one day of age or with E. tenella at 14 days of age or both. The control group was left uninfected and was mock inoculated with phosphate buffer saline (PBS) Mortality rates, body weights, cecal lesions, and viremia of infected chickens in each group were evaluated. Immune status was evaluated by measuring several parameters: immune organ weight/body weight index, specific humoral responses to inactivated NDV vaccine and to inoculated E. tenella, proportions of blood CD3+CD4+ and CD3+CD8a+ lymphocytes and transcriptional levels of cytokines in blood and cecal tonsils. The results show that co infections of ALV J and E. tenella induced a higher mortality rate and a lower body weight in SPF chickens compared to single pathogen infection. In co infected chickens, ALV J accelerated the disease symptoms induced by E. tenella, and the E. tenella extended the ALV J viremia. Thymus atrophy, decrease in the humoral response levels to pathogens and the NDV vaccine, modifications in the blood lymphocyte sub populations and transcriptional cytokine disorders were found in co infected chickens compared to chickens infected with one pathogen alone and to controls. We underline a synergy between ALV J and E. tenella that results in increasing pathogenesis in SPF chickens.
Veterinary immunology and immunopathology