A/California/7/2009与A/California/4/2009病毒感染力比较

目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009（CA7）与A/California/4/2009（CA4）两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。

Infectivity Comparison between A/California/7/2009 and A/California/4/2009

Objective To compare the infectivity of H1 subtype influenza A viruses A/California/7/2009 and A/California/4/2009,which the nucleotide sequence homology of two subtypes is 99% in BALB/c mice.Methods（A/California/7/2009（CA7）） and A/California/4/2009（CA4） were additionally used in infectivity studies.Female BALB/c mice（15～18 g） were anesthetized by inhalation of ether and inoculated intranasally with 0.03 mL of infectious virus CA4 or CA7.Briefly,mice were infected with ten-fold dilutions of each virus.Mice were observed daily for 8 days for clinical signs of infection and day of survival.Results CA4 and CA7 infected mice in the same TCID50.2 mice of 10 infected by CA4 died in 14 days,on the other hand 10 mice infected CA7 were all dead in 8 days.Severe interstitial pneumonia characterized by necrosis and inflammation cells in mice infected CA7 and mild interstitial pneumonia in mice infected CA4.Conclusion The data demonstrate that the CA7 has more infectivity than CA4 in the same TCID50.