The Study Of Effects Of Mimic Environmental Contamination Factors On IBV M41

Avian infectious bronchitis virus (IBV), the prototype species of the family Coronaviridae, causes ahighly contagious respiratory disease of chickens. In twenties years, scientists have found that IBVserotype is complicated and easy to vary, and its strains are more and more, the propagative rangeof IB becomes larger, too. People have realized these changes had some matter with environmentalpollution. Scientists indicate that the breakdown in ecological balance induces new contagiousdiseases. Four species of chemical materials(Roxarson, Erinitrit, NB, GE) that are factors ofenvironmental pollution. The effects of drugs on IBV was studied in three ways: adding medicineto the cultured CEK cell before adding virus, adding virus to the cultured CEK cell before addingmedicine, and adding medicine and virus to the cultured CEK cell after they acted for a while. Theeffect was estimated in terms of Cytopathic effect, viral titre yields and OD values of MTTcolorimetric method to determine the respective influence on virus penetration and viruspropagation. And study variation in M41 IBV S1 gene by sequence analysis.In the CEK cell culture experiment in vitro, the cytotoxic influence of different drugs diluted atmultiple proportions was studied to determine the highest non-toxic concentration. The resultsindicated that high dose could inhibit the proliferation of CEK and made CEK survive shorter time.At middle dose, Roxarson, Erinitrit, NB made CEK survive shorter time and GE had not cytoxicity,while low dose of four drugs hadn't cytoxicity.The effects of Roxarson, Erinitrit, NB, GE on IBV were studied by observation of cytopathiceffect (CPE) and agglutination titer. The results showed that Roxarson and NB facilitatedproliferation of IBV when they were added into the CEK ahead of IBV, and they did not when theaddition after than IBV and after incubation. Erinitrit and GE didn't affect the proliferation of IBVno matter how to add into the CEK.The results of sequence analysis showed that only one drug didn't enhance genovariation inIBV,while the mixture of four drugs can promote the variation in S1 gene.