Comparison Of Four Diagnoses Methods For Classical Swine Fever

Classical swine fever (CSF ) caused by Classical swine fever virus (CSFV) is one of viral diseases with important and economic significance, which has serious effects on pig industry. In 1984 Office International Des Epizooties (OIE ) classified CSF as one of 15 kinds of Type A of animal main strongly infectious diseases. Our country classified this disease as first animal's epidemic disease. New edition "Terrestrial Animal Health Code " released in 2005 listed CSF in disease catalog which is asked to be notified by OIE when it breaks out .To diagnosis of the swine fever because of different virulence between different strains of CSFV, its clinical symptom and pathology change differ significantly during the dissection and examination after death of ill pigs, and generally it is very difficult to make a definite diagnosis for CSF only according to the clinical manifestation and pathology. Setting up effective and accurate laboratory detection method of CSFV is very important to prevent and control CSF.This research using 4 kinds of methods including CSFV separation and identification, fluorescence antibody method, reverse transcription-polymerase chain reaction (RT-PCR), sandwich ELISA, respectively examined and compared strains of CSFV in 23 kinds of tissues .1. The research separated IgG from positive serum of CSF and mark fluorescence was plained on the IgG to get fluorescence antibody of CSFV. This fluorescence antibody can be used to detected CSFV in cells and pathological material with CSFV. PK-15 cell which infected CSFV and pathological material with CSFV were examined by the fluorescence antibody we made, their results are both positive and those of control are both negative. This result indicated that prepared CSF fluorescence antibody can be used to detect CSFV in pathological material and PK-15 cell infected by CSFV. Using straight fluorescence antibody method may confirm the position of CSFV hyperplasia in infecting cells, which has offered practical technique for CSF diagnosing in laboratories.2. The method of the detection for CSFV by RT-PCR has been established, which has advantage with high checkout rate and accuracy. And it is also relatively short in detection time. Generally the result can be gotten in 4- 6 h after getting pathological material of this disease and interest gene E2 cloned by RT-PCR can be regarded as the basic material to study CSFV molecule epidemiology. By determining variation of E2 gene of different pathological materials, variation epidemic trend and molecule evolve the characteristic of CSFV could be known and concluded, which is very significant to understand epidemic characteristic and trend of CSF.3. This research utilized 4 kinds of different methods to examine CSFV in the same pathological material, which indicated that the detection results of CSFV separation and identification and RT-PCR are the same; but the result by the fluorescence antibody method is very unsatisfactory, where there are a large number of samples that can't be judged, and except that a copy of pathological material caused the false negative because of improperly being kept the test results of other pathological material are the same as those of separation and identification of CSFV. So the method of RT-PCR could be used to measure CSFV in conditional laboratories and this method is more easy on operating than that of separation and identification of CSFV, and at the same time it is not restricted by the cell culture and it can deal with a large number of samples needed to be measured. While gauging CSFV in the fresh pathological material of disease, sandwich ELISA method can be selected which operation is more simple and convenient and also is easy to be popularized in the basic unit, and this method can be used as the first-selected method during general survey of the swine fever.