Studies on the immune response of foot and mouth disease vaccine type Asia-1 in pregnant ewes, lambs and evaluation of type O vaccine by challenge.
1994
Nair S.P. | Sen A.K.
Seven pregnant ewes at the 10th to 12th week of pregnancy were vaccinated with foot-and-mouth disease (FMD) vaccine type Asia-1. All pregnant animals responded well with antibody production without any adverse effects. The maximum antibody titre was noted 3 to 4 weeks after the vaccination. In the colostrum a high level of maternal antibodies persisted from 12 hrs to 6 weeks after birth. Irrespective of the presence of the maternal antobodies, the vaccinated lambs responded with antibody production within the first week of vaccination. The antibodies persisted up to the 12th week of vaccination. In another experiment five sheep were vaccinated with FMD type O vaccine and challenged with 10,000 TCID50 of virulent type O cell culture-adapted virus. The antibody titres in the vaccinated animals prior to challenge ranged between 1.26 to 1.65, while the four control sheep remained free from detectable antibody against virus type O. Pyrexia and viraemia developed present in all the control sheep but were absent in the vaccinated ones. Characteristic primary lesions on the dorsum of the tongue were observed after 48 hrs of virus challenge in the control sheep but were absent in the vaccinated ones.
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