Study of the effect of vaccination with the homologous SG33 strain of myxomatosis virus on the immune system development in rabbits under field conditions representative of the Epizootic Rabbit Entheropathy Syndrome (ERE).



The immunodepressive effect of a homologous live attenuated vaccine against myxomatosis SG33 strain was assessed under field conditions. A comparison between vaccinated and unvaccinated control rabbits was done. The animals were reared in three different farms: a first one in which no case of rabbit epizootic enteropathy (ERE) in fattening rabbits had been diagnosed, and two other ones in which an ERE syndrome had been diagnosed during the last three months. Lymphoid tissue of the thymus had been developed between birth and 30 days of age. The method implemented in the study did not allow to show qualitative nor quantitative differences between studied groups, vaccinated or unvaccinated. Lymphoid tissue of the thymus of the appendix wass well developed in 30 and more day-old animals. No differences in histopathological studies between vaccinated and unvaccinated were shown. Nevertheless, immunodepression had been assessed regarding only one parameter. lt cannot be definitively concluded whether the SG33 has an influence or not.