| Classical swine fever (CSF or Hog Cholera, HC) is a highly contagious disease in pigs caused by the Classical Swine Fever virus (CSFV) belonging to the Flaviviridae family, the infection can run an acute, subacute, chronic, atypical, or inapparent course.a list A disease of Office International des Epizooties (OIE), and still has a worldwide distribution. In our country, the widely use of hog cholera lapinized vaccine controlled the acute and subacute of classical swine fever effectively. In recent years, epidemic situation of CSF in China have taken great changes, chronic, atypical, or inapparent course were prominent clinical signs,this is more difficult to recognize, and this favors the spread of these strains. To propse new methods for the integrated control of classical swine fever, the quantification detection of virus antigen in hog cholera lapinized vaccine and the immunity proceduce for classical swine fever were peformed in depth.This research consists of three parts as follows:Partâ… : Quantification detection of virus antigen simply and rapidly is one of the technologies difficult to solve in hog cholera lapinized vaccine (HCLV) production process. In this experiment, the classical swine fever antigen/serum ELISA kit (IDEXX HerdCheck Co.) was used to detect the virus antigen quantity of 24 batches of semi-finished HCLV and 21 batches of finished HCLV. The results indicated that high accordance rate (95.83%) was present between the ELISA assay and rabbit heat reaction for the antigen amount detection of semi-finished HCLV. In addition,the sensitivity of the antigen/serum ELISA kit reached to 20 times dosages every bottle(or 109 copys every bottle). However, this method could not distinguish the classical swine fever virus antigen from Bovine viral diarrhea virus antigen. As a result, the classical swine fever antigen/serum ELISA kit (IDEXX HerdCheck Co.) was stably, simply and rapidly used in the detection of the the virus antigen quantity of the HCLV, and it provides a convenient and stable method in the quality control of HCLV production process.Partâ…¡: At present in practice of classical swine fever preventing and controlling, the effect of precolostral vaccination to antibody level change and protection still existence dispute. In this experiment, three nest piglets were used to test precolostral vaccination, these piglets were injected with hog cholera lapinized vaccine 0.5 dose/each 1 to 1.5 hours before intake. Two nest piglets were selected to use the routine immunity procedure, these piglets were were injected with hog cholera lapinized vaccine 1 dose/each at 21 days old. The classical swine fever antibody ELISA kit (IDEXX HerdCheck Co.) was used to detect the serum antibody levels at 0, 20, 40, 60 days old. The results showed that precolostral vaccination can perform a good protection in a low maternal antibody levels, but the routine immunity procedure can not protect piglets from classical swine fever before the second vaccination.Partâ…¢: The present study examines whether such vaccinations have adverse effects on both sows and piglets. The study also aims at determining whether injection of HCLV in pregnant sows would result in maternal antibody levels in their litters. And according to maternal antibody levels of the piglets, the best immunity procedure were established. Experiment 1: pregnant and multiparity sows with similar breed, age and fetus frequency were selected, these sows were injected with hog cholera lapinized vaccine 2 doses/each during mid-gestation (50~59 days, 40~49 days, 30~39 days before childborn), five piglets of each nest were randomly selected, and the classical swine fever antibody ELISA kit (IDEXX HerdCheck Co.) was used to detect the serum antibody levels, these piglets were injected with hog cholera lapinized vaccine at 60days old. In control group, the pregnant sows were not injected with hog cholera lapinized vaccine, their litters were selcected to use the routine immunity procedure (first imminty at 25 days old, second imminty at 60days old). Experiment 2: On the basis of experiment 1, three pregnant sows were injected with hog cholera lapinized vaccine 2 doses/each during mid-gestation (40~49 days before childborn), five piglets of each nest were randomly selected to injected with hog cholera lapinized vaccine at 60 days old, and multiple injectde at 85 days old. In control group, the pregnant sows were not injected with hog cholera lapinized vaccine during gestation, the immunity procedure were established according to maternal antibody levels of the piglets. The results showed that hog cholera lapinized vaccine was safe to pregnant sows and their litters, the survival rate is 91.30% in Experiment group and 90.63% in conrol group,the result was indistinctively difference. To the piglets, once time of immunity at 60 days old is not enough, twice time of immunity can perform a good protection. |
