Influence of avian reovirus S 1133 strain on the efficacy of ND vaccination in chicks
1991
Artopiou, G.M (Laboratory of Microbiology and Infectious Diseases) | Iordanidis, I.P. | Artopios, V.E. (Aristotelion Univ., Thessaloniki (Greece). Faculty of Veterinary Medicine. Pathological Clinic of Poultry)
It is well known that avian reoviruses have an immunosuppressive action and affect the ND vaccination efficacy. The purpose of the present study was to investigate the effect of a highly attenuated S1133 reovirus vaccine on the efficacy of a live ND vaccine, which is largely in use in Greece. Sixty chicks, without maternal antibodies to avian reoviruses, were divided into 3 groups of 20. The chicks of the first group were served as unvaccinated controls. Two vaccinations were applied on the chicks of the second group. Avian reovirus strain S1133 administered on their 7th day of age, and the ND La-sota strain 10 days later. The chicks of the third group were vaccinated only once, with the ND La-sota strain on their 17th day of age. The presence of ND virus HAI maternal antibodies was checked before vaccination. All chicks were weighed and then slaughtered fifteen days after the ND vaccination. At the same time serum samples were collected. Spleen and bursa of Fabricius were weighed and examined macroscopically. Changes were observed only in chicks of the second group. These were an increase of the spleen and decrease of the bursae of Fabricius weight, but they were considered as not important, statistically (p0.05). The HAI antibody titres were not affected. It is concluded that the efficacy of ND vaccination with live vaccine is not affected by S1133 attenuated vaccine, although slight changes are induced on the lymphatic system of vaccinated chicks.
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