Studies On Newcastle Disease Virus ? Activities And Its Mechanisms Of Compound Radix Aristolochiae

Newcastle disease is an avian infectious diseasecaused by Newcastle disease viruswith high death rate, for which there is no effective treatment currently. There are few reports of treatment of the disease with chinese herbal medicine..In order to explores the new way of treating Newcastle disease with compounded Chinese herbal medicine (compound radix aristolochiae), and researches its basic treatment principle. We chooses Aristolochia debilis root, Oxalis corniculata herb, Vitax negundo stem or leaf three kinds of Chinese herbal medicine to formulate "compound radix aristolochiae".Using safe concentration, we performed the antiviral medicine in chicken embryo fibroblast, chick embryo and chicks,respectively.The results are as follows:1.In cell cultrue experiment, the best antiviral effects were archieved when the virus was pretreated for two hours with the compounded medcine prior to the viral inoculation. These results indicate the compounded medicine can direct inactivate the virus.2.In experiments with chicken embryo, the 60% of the protective effect on the viability of the embryo was archieved when the virus was pretreated with medicine for 2 hours. However, if the embryos were pretreated with the compound for two hours before the viral inoculation,36% of the protection could be archived. Finally, no protection was observed when the embroys were pre-infected with virus before the treatment with the compound. These results collectively suggest the antiviral effects of the compound is mainly through direct viral inactivation. Secondarily, as 36% of the protection could be archived through pretreatment with compound, it is also possible the compound may enhance the resistence of embryos to the viral infection.3.In the chicksclinical trials,100% protection to the viral challenge was archieved when the chicks were fed with the feed containing 8.3% of the compound for a week; greater then 40% protection was archieved if the chicks were fed with the compound (8.3%) and viral inoculated at same time; no protection (100% death) by the compound was observed if the chicks became symptomatic. Our results indicate that the compound confers protection against Newcasttle viral disease, but has no therapeutic effects on the viral disease.