| Summary |
Twenty-two hog cholera antibody free secondary SPF pigs with 5-7 weeks of age were divided into 5 groups. Pigs of 1 and 2 were injected intramascularly with one dose of the live vaccines of the cell culture-adapted LPC-TS strain and LPC-China strain, respectively. Pigs of groups 3 and 4 were injected with the inactivated oily vaccines of LPC-TS strain and HC-TD field strain twice at an interval of 4 weeks. Geometric mean neutralizing antibody titer at 4 weeks after vaccination of the pigs of groups 1, 2, and 3 were 1 : 363, 1 : 436, and 1: 38, respectively. No antibody response was detected in the pigs of group 4.
After challenge with 1040 MLD of the virulent ALD virus, mild febrile reaction (<41 ·c) and symptoms were found in all pigs which were vaccinated with 2 live vaccines (groups 1 and 2) and survived without shedding. Over 41 ·c fever was found in the pigs vaccinated with 2 inactivated vaccines and all pigs vaccinated with the inactivated HC-TD strain and controls developed severe symptoms and died after challenge. However, 2 pigs which were vaccinated with the inactivated LPC-TS strain survived.
Gross lesions, such as spleen infarction, peripheral hemorrhage of lymph nodes and petechial hemorrhage of kidney were observed in the pigs vaccinated with the inactivated vaccines (excluded 1 pig vaccinated with the LPC-TS strain). However, nothing happened in the pigs vaccinated with the live vaccines. Results imply that promotion of the quality of inactivated vaccine is needed.
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