Molecular Epidemiological Survey Of PRRSV In Henan Province And In Vitro Screening Of Antiviral Traditional Chinese Medicine Unit

Porcine reproduction and respiratory syndrome (PRRS) which caused by porcinereproduction and respiratory syndrome (PRRSV) is an acute highly contagious diseasein pigs. Until now, no drug has shown efficacy, there is only rely on a vaccine toprevent the disease. PRRSV variation field of real-time monitoring and find effectivetreatment for drug prevention and treatment of PRRS of paramount importance. Inrecent years, constantly mutates PRRSV brought greater difficulties to the preventionand treatment of PRRS. The most important in controlling PRRS are surveillance ofPRRS and the effective drug.In this study,82pieces of positive PRRS samples from Henan province weredetected by RT-PCR to looking for the variation characteristics of PRRSV strains.Results showed, Eighty two complete PRRSV ORF5s were amplified successfullyfrom the samples, and the determination for sequences indicated that the similarity ofamong these sequences was between94.2%and100%. Compared to VR-2332I, JXAand LV,the similarity of these sequences was86.9%~89.7%,95.7%~99.7%,60.8%~66.3%respectively. The part of Nsp2gene for masccline samples were alsoamplified, gene homology analysis was performed with Nsp2of VR-2332deposited inGenBank after determination for sequences, and the two points and90bp bases deletedwere found in all of the twenty one Nsp2genes, prompt newly epidemic strain inHenan province were highly pathogenic PRRSV. This study identified the vatiations ofprevalent PRRSV for ORF5gene and Nsp2gene in the western of Henan province,and provided some basis for controlling PRRS in this area.To looking for the effective Chinese herbal monomer on PRRSV and it’s effectiveconcentration, ten Chinese herbal monomer were used in anti-virus experiment in vitro.Anti-virus mechanism of the effective anti-PRRSV was studied in three ways: adding medicine to the cultured Marc-145cell before adding virus, adding virus to thecultured Marc-145cell before adding medicine, and adding medicine and virus to thecultured Marc-145cell after the acted for a while. Antiviral activity against PRRSVwas estimated in terms of Cytopathic effect, viral titre yields and OD values of MTTcolorimetric method to determine the respective effects of anti-penetration activityagainst virus. Results showed: The TCID50of this strain is10-5.5, and screen out foureffective Chinese herbal monomer: chlorogenic acid and baicalin, quinine acids andphillyrin. their highest non-toxic concentration respectively were160μM,20μM,3000μM,100μM. They all have good effect of blocking adsorption (protection rate arein50%above); the anti-virus copy activity of Green original acid and ForsythiaGlycoside also were obviously; the quinine acid and green original acid and ForsythiaGlycoside also have good directly killing effect. The best Chinese herbal monomer inthe three ways was screened out: chlorogenic acid and phillyrin,both of them haveshown better protection on cells.