甲型流感

病毒也不仅仅只有坏处，有时候还能帮助我们。很奇怪吧？来看看这个故事就明白了!

A Review on 2009 Influenza A Virus

[Objective] The paper was to introduce the research progress of 2009 influenza A virus. [Method] 2009 influenza A virus was introduced from the aspects of classification and host, virology, molecular characteristics and vaccine. [Result] A novel influenza A/H1N1 virus emerged in early April 2009 quickly spread worldwide through human-to-human transmission. The virus contained a group of novel gene segments, the nearest known precursor was the virus found in swine. The virus appeared to retain the potential to infect swine again and thus continued reassort with swine viruses. All registered 2009 influenza A vaccines were tested for safety and immunogenicity in clinical trials on human volunteers, and all vaccines were found to be safe, single dose of vaccine could cause protective antibody responses. [Conclusion] The paper provided basis for further study on 2009 influenza A virus.

H5N1 influenza viruses： outbreaks and biological properties

All known subtypes of influenza A viruses are maintained in wild waterfowl, the natural reservoir of these viruses. Influenza A viruses are isolated from a variety of animal species with varying morbidity and mortality rates. More importantly, influenza A viruses cause respiratory disease in humans with potentially fatal outcome. Local or global outbreaks in humans are typically characterized by excess hospitalizations and deaths. In 1997, highly pathogenic avian influenza viruses of the H5N1 subtype emerged in Hong Kong that transmitted to humans, resulting in the first documented cases of human death by avian influenza virus infection. A new outbreak started in July 2003 in poultry in Vietnam, Indonesia, and Thailand, and highly pathogenic avian H5N1 influenza viruses have since spread throughout Asia and into Europe and Africa. These viruses continue to infect humans with a high mortality rate and cause worldwide concern of a looming pandemic. Moreover, H5N1 virus outbreaks have had devastating effects on the poultry industries throughout Asia. Since H5N1 virus outbreaks appear to originate from Southern China, we here examine H5N1 influenza viruses in China, with an emphasis on their biological properties.

Conservation of T cell epitopes between seasonal influenza viruses and the novel influenza A H7N9 virus

A novel avian influenza A(H7N9) virus recently emerged in the Yangtze River delta and caused diseases, often severe, in over 130 people. This H7N9 virus appeared to infect humans with greater ease than previous avian influenza virus subtypes such as H5N1 and H9N2. While there are other potential explanations for this large number of human infections with an avian influenza virus, we investigated whether a lack of conserved T-cell epitopes between endemic H1N1 and H3N2 influenza viruses and the novel H7N9 virus contributes to this observation. Here we demonstrate that a number of T cell epitopes are conserved between endemic H1N1 and H3N2 viruses and H7N9 virus. Most of these conserved epitopes are from viral internal proteins. The extent of conservation between endemic human seasonal influenza and avian influenza H7N9 was comparable to that with the highly pathogenic avian influenza H5N1. Thus, the ease of inter-species transmission of H7N9 viruses(compared with avian H5N1 viruses) cannot be attributed to the lack of conservation of such T cell epitopes. On the contrary, our findings predict significant T-cell based cross-reactions in the human population to the novel H7N9 virus. Our findings also have implications for H7N9 virus vaccine design.

Antigenic variation of the human influenza A(H3N2) virus during the 2014–2015 winter season

The human influenza A （H3N2） virus dominated the 2014-2015 winter season in many countries and caused massive morbid- ity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 （A/Switzerland/9715293/2013-1ike strains） and HK14 （A/Hong Kong/5738/2014-1ike strains）, co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in China's Mainland, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an im- portant role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains.

Combination of ribavirin and reduning protects mice against severe pneumonia induced by H1N1 influenza a virus

OBJECTIVE:To investigate the effects of ribavirin administration combined with Reduning in a mouse model of influenza A(H1N1)-induced severe pneumonia.METHODS:Influenza A/Beijing/501/2009(H1N1)-infected C57BL/6 mice were randomly divided into four experimental groups treated with either a mock injection of phosphate-buffered saline(PBS),ribavirin(66.6 mg/kg daily)or Reduning(86.6 mg/kg daily),or a combination of both,for 7 days.Mice were monitored for clinical signs and survival,and body weight was measured daily for 14 days.Virus titer,lung wet-to-dry ratios,pathology and cytokines including interleukin(IL)-6,IL-10,and interferon(IFN)-γwere assayed on different days.RESULTS:In the untreated group injected with phosphate buffer saline,all the mice died of the infection.The survival rate of mice treated with Reduning was only 10%,whereas 100%of the ribavirin-and the combination-treated mice survived.Low lung viral loads indicated that ribavirin significantly inhibited virus replication,whereas Reduning did not.Lung wet-to-dry ratios demonstrated that both ribavirin and Reduning,administered together or separately,reduced acute lung edema compared with results in the untreated group.Pathology analyses also showed that treatment with a combination of both drugs relieved pathological lesions,whereas the single drug treatment did not.Levels of IL-6,IL-10 and IFN-γin mice treated with ribavirin or the combination of both ribavirin and Reduning were all significantly lower than in the untreated group,especially in the combination-treated group.In addition,Reduning administration significantly decreased both IL-6 and IL-10production but had no effect on IFN-γ.CONCLUSION:Due to the synergistic effect of antiviral and antiinflammation,the combination of ribavirin and Reduning could be an effective treatment for severe H1N1 which was considered to be significant to delayed antiviral and drug resistant.

Optimal treatment strategy of an avian influenza model with latency

Avian influenza, caused by influenza A viruses, has received worldwide attention over recent years. In this study, we formulate a mathematical model for avian influenza that includes human human transmission and incorporates the effects of infection latency and treatments. We investigate the essential dynamics of the model through an equilibrium analysis. Meanwhile, we explore effective treatment strategies to control avian influenza outbreaks using optimal control theory. Our results show that strategically deployed medical treatments can significantly reduce the numbers of exposed and infection persons.