Infection and replication of avian influenza H5N1 virus in an infected human.
The highly pathogenic avian influenza H5N1 viruses usually cause severe diseases and high mortality in infected humans. However, the tissue tropism and underlying pathogenesis of H5N1 virus infection in humans have not been clearly elucidated yet. In this study, an autopsy was conducted to better understand H5N1 virus distributions in tissues of infected humans, and whether H5N1 virus can replicate in extrapulmonary tissues. We found that the lungs had the higher viral load than the spleen, whereas no detectable viruses in tissues of heart, liver, kidney, large intestine, small intestine, or brain. Specifically, the viral load was higher in the left lung (7.1 log10 copies per ml) in relation to the right lung (5.7 log10 copies per ml), resulting in more severe pathological damage in the left lung, and lung tissues contained both positive- and negative-stranded viral RNA. However, there existed a low level of H5N1 viruses in the spleen (3.8 log10 copies per ml), with the absence of positive-stranded viral RNA. Our results indicate that replication of H5N1 viruses mainly occurs in the lungs, and the degree of lung damage is highly correlated with the viral load in the lungs. The low-load viruses in the spleen might be introduced through blood circulation or other ways.
Zhou
Jing-Jiao
JJ
Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, People's Republic of China.
Fang
Dan-Yun
DY
Fu
Jie
J
Tian
Jiang
J
Zhou
Jun-Mei
JM
Yan
Hui-Jun
HJ
Liang
Yu
Y
Jiang
Li-Fang
LF
D001344:Autopsy; D002681:China; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000473:pathology* / Q000821:virology*; D008168:Lung / Q000473:pathology / Q000821:virology; D013154:Spleen / Q000821:virology