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目的 了解水环境的理化因素对国内新城疫病毒流行株感染力的影响,以及新城疫病毒强、弱毒株对理化因素耐受性差别.方法 测定3株NDV强毒株和3株弱毒株在不同温度(20、37和54℃)、盐度(0、15和30 g/L)和pH(4.4、5.4和7.4)条件下保存时,病毒的鸡胚半数感染量(EID50)随时间的动态变化.使用线性回归方程分析不同理化条件下病毒的感染持续期.结果 对照组用磷酸盐缓冲液(pH7.4和20℃)保存时,病毒EID50保持相对稳定,RT(病毒感染力降低90％所需天数)可达26.25～64.52d;在30 g/L NaC1条件下,病毒RT为5.78～24.51 d;在pH4.4条件下病毒的EID50下降较快,RT在4.54～10.66 d之间;在57℃条件下,病毒的EID50迅速下降,RT＜1 d.NDV强、弱毒株RT值相似.结论 酸度增加和盐度增高可一定程度上缩短病毒在水中的存活时间,而水温增高则导致病毒感染力的迅速降低.病毒对理化因素的耐受力因毒株而异,但与病毒的毒力无关.因此可利用不利于病毒存活的理化因素如高温或化学品进行消毒,减少禽舍或环境中新城疫病毒的存在,阻断病毒传播.“,”Objectives To study the effects of physiochemical factors on the infectivity of Newcastle disease viruses (NDVs) and to compare the tolerance of NDVs with varying levels of virulence to different physiochemical conditions.Method The EID50 of 3 virulent viruses and 3 avirulent viruses was determined with a phosphate buffer solution under different conditions:a pH of 4.4,5.4,and 7.4,a salinity of 0,15,and 30 g/L,and a temperature of 20,37,and 54℃.The duration of viral infection was then analyzed using linear regression analysis.Results The 6 viruses had a relatively similar EID50 at a pH of 7.4 and a temperature of 20℃,and the RT values (the time required for the infectivity of each virus strain to decrease by 90％) ranged from 26.25 to 64.52 days.When 30g/L of NaC1 was added to the solution,RT ranged from 5.78 to 24.51 days.When viruses were kept at a pH of 4.4,RT ranged from 4.54 to 10.66 days.When viruses were kept at a temperature of 57 ℃,the EID50 decreased quickly and RT dropped sharply to less than 1 day.In addition,virulent and avirulent NDV strains had a similar RT.Conclusion In conclusion,an increase in acidity or salinity moderately decreased the persistence of viral infectivity in water,while an increase in temperature resulted in a quick decrease in the duration of viral infectivity.Different NDV strains reacted differently to physicochemical factors,regardless of their level of virulence.Results indicated that a high temperature and/or chemicals are effective disinfection measures to inhibit the prevalence,infection,and transmission of NDVs in chicken coops and their surroundings.