These are stronger , more invasive viruses which are not recommended unless you have this highly virulent form of ibd 这些都是毒力强些的疫苗，不建议使用毒力再强些的疫苗除非有这种高致病力的ibd存在。
Especially the highly pathogenic avian influenza virus , which can cause up to 100 % outbreak rate with / or death rate and even can infect mankind and kill them 尤其是高致病力禽流感可导致高达100发病率和或死亡率。并可直接感染人并致人死亡。
In other words , people would be infected with a very weak form of hsv , one that is sufficient to trigger a sustained immune response but too frail to trigger disease outbreaks 即人们需要感染一种致病力弱的hsv ，这种病毒足以激发持久的免疫反应，但又不足以致病。
Halford is specifically investigating a protein in hsv called icp0 . " if i take away the gene that codes for that protein , the virus is really weakened , " he said Halford专门研究hsv中的一种称为icp0的蛋白。他说： “如果我去除编码这种蛋白的基因，病毒的致病力的确会被削弱。 ”
Signs of high mortality and loss of productivity characterized ai . the avian immune function was inhibited , and then was infected by other bacterium and virus 禽流感主要表现为，高致病力毒株致鸡只的大量死亡，非高致病力毒株引起产蛋量下降，免疫功能障碍而继发细菌或病毒的感染。
This result indicated that the virus pd70344v derived from the infectious molecular clone is a highly virulent strain which had inherited main characters from its parental virus dv 这一结果说明本文所构建的感染性分子克隆株pd70344v具有其亲本dv株的基本生物学性状，是一株具有高致病力的衍生病毒。
There is minor variation in some nucleotide sequences . and the results indicate by analysis that the deduced amino acid sequence contains characteristic sequence of splitting site of high pathogenic ai strain 同时分析表明该核苷酸含有强毒株裂解位点的特征性序列，从而从分子水平证明了该病毒分离株为高致病力毒株。
Based on the host reaction and cluster analysis of disease severity , the 57 isolates of venturia inaequalis could be divided into three categories : strong ( pathotype ) , intermediate ( pathotype ) and weak pathogenicity ( pathotype ) respectively 根据寄主对病菌的反应类型并结合病害严重度的聚类分析结果，可将57株苹果黑星病菌菌株划分为3个类群：强致病力型、中等致病力型、弱致病力型。
In order to explicit the pathogenicity differentiation of venturia inaequalis in fields , three apple cultivars were individually inoculated with 57 representative single spore isolates of venturia inaequalis collected respectively from different apple producing areas in china , england and india 摘要为了明确田间苹果黑星病菌致病力的分化情况，选取中国、英国、印度3个国家不同苹果产区的57株有代表性的苹果黑星病菌株，分别接种嘎啦、富士、秦冠3个寄主品种进行致病力测定。
