两株H5N1高致病性禽流感病毒对小鼠的致病力研究

Pathogenicity of two highly pathogenic avian influenza (H5N1) viruses in mice

为比较2株H5N1亚型高致病性禽流感病毒(HPAIV)对哺乳动物的致病力,本研究选取了A/Anhui/2/05(AH/2/05)和A/Sichuan/81/05(SC/81/05)两株病毒,采用低剂量(10 EID50)感染小鼠模型,并就两株病毒对小鼠的致病力差异进行检测。结果表明AH/2/05感染后小鼠出现体重下降和神经症状,并可致死部分小鼠;SC/81/05感染小鼠后,小鼠无任何明显的症状,体重、食欲、精神状态均不受影响。AH/2/05感染后病毒可在小鼠的全身复制,病毒在小鼠体内的存活时间可以长达14 d。SC/81/05感染后病毒仅在小鼠的肺脏中复制,并且仅能够在感染后的3 d和5 d分离到病毒。病理学检测显示,AH/2/05感染后病毒存在于小鼠的各脏器细胞并且引起小鼠脏器组织的严重病理变化,而SC/81/05感染后并未对小鼠组织脏器造成明显的病理变化。本研究结果揭示了人源和禽源H5N1禽流感病毒低剂量感染对小鼠的致病差异,同时为进一步研究H5N1亚型HPAIV在哺乳动物中的感染和致病能力提供了相关的实验依据。

H5N1 high pathogenicity avian influenza virus （HPAIV） has posed great threat to the human public health.In this report,the mice were inoculated by a low dose （101 EID50） of the H5N1 influenza viruses,A/Anhui/2/05 （AH/2/05） and A/Chicken/Sichuan/81/2005 （SC/81/05） to imitate nature infection,respectively.The mice infected with AH/2/05 showed significant clinical signs after infection,including bodyweight descent and neurological symptoms,and the viral replication was detected in all organ tissues of the mice collected on day 3,5,7,10 and 14 post-inoculation （PI）.Whereas,no disease symptoms were observed in the mice after infection with SC/81/05,and the viral replications were only detected in lungs.In addition,histopathological examinations showed that AH/2/05 caused severe lesions to the most organs of the mice; however,the SC/81/05 induced only mild lesion in the lung tissue.These results demonstrated that the two H5N1 viruses had different pathogenic properties in mice with low-dose infection which provided the basis for a better understanding the infection and pathogenesis of H5N1 virus in nature.