In the study of hog cholera virus multiplication in experimentally incculated pigs, the writers have aheaxly descriEei that the patterns of virulent ALD virus infection can ke divided into 3 phases; the lymphatic viremia and visceral phases. Only the lymphatic phase was present in the infection with attenuated GPE-virus.
In this rarer, infection of lapinized hog cholera virus in vathnatd 20 SPF pigs, 2 pigs killer! daily over a reriorl from the first through 10th thy pctincculation, was carefully studied by the FAOCT 2-step methcd. The classification of patterns of hog cholera infection as well as the immunizaton mechanism of the attenua virus vaooine was further elucidated. The data axe summaril as follows:
1 ,The lapinizrd hog cholera virus was initially dette1 from the tonsils, or spleen, mandibular lymph nc&s on the 3rd thy pstinoculation. Tonsil was the only organ, from which the virus was constantly isolated and exhibited the highest virus titer among the virus-pceitive organs. Spleen and various lymph nodes showed inconsistently poGitive virus isolation from 3rd day through 8th day postincoilation. The rest except lung and trachea, each pvo€itive case, were all negative virus deation. Thus, only the lymphatic phase was present in the infection with the lapinb!d virus. The establishment of immunity in vaccinand pigs with the attenuat! hog cholera virus must ie completed mainly at the lymphatic phase of infection.
2.The forms of multiplication of the lapinil virus in tonsils, spleen and mandibular lymph nodes indicated distinct curve shapes, Of them, the curve of tonsils was the mcct di inci and tothehighest virus titer of l(Y’3.5 TCIDSCVgon the?-8th day pDstincculation while spleen and mandibular lymph nodes reacher! the highest virus of 10”2.5 TCE)SWg on the 4thor5th day postinccilatioa The other pothtive ones showed low titer of 1CN TCIDSCVg.
3.lnterferon and neualization antibody were not demonstxai from the serum of pigs incxulatl with the lapinid live vaccine in all cases of this experiment, (In the
previous experiment, the neutralization antibcdy was demonstratl as early as 10 days after vaccination in some cases.)