The outbreak of high-pathogenicity avian influenza viruses causing severe illness and death has severely disrupted poultry production and trade and posed a significant threat to public health.In recent thirty years,the virus has been endemic in Southeast Asia,China,Europe and Africa.Although the virus shows little ability of transmission between humans,a process of genetic reassortment could occur in a human co-infected with avian influenza A virus and a human strain of influenza A virus.So H5N1 represents a potential source of the next pandemic influenza.Direct avian-human H5N1 virus transmission is the predominant means of human infection,through direct contact with infected birds and virus-contaminated fomites or with fertilizer containing poultry feces.After several rounds of infection the viruses acquire the mutations required for crossing species barrier and infect a range of mammalian species including humans.Currently,vaccination is still the key strategy to prevent severe illness and death from pandemic influenza.Antiviral drugs such as NA inhibitors play an important role in antiviral treatment.The features of avian influenza virus and its mechanism of transmission in animals and humans are herewith reviewed,and the pathopoiesis of the virus,the current status of vaccine development and antiviral treatment are also discussed.

To identify the pathogen of severe acute respiratory syndrome (SARS ), suckling mice and Vero E6 cells were inoculated with the lung samples from autopsied patients with SARS. The tissues obtained from mice were examined with light microscopy and electron microscope(TEM). The infected cells and supernatants were also examined under TEM. The primary hiatopathological leisions in the lungs were wall of lung alveolies thickened and alveolar cavities narrowed. The hepatocytes were swollen and undergone vacuolar and hydropic degeneration. A large quantity of coronavirus like particles could be observed in the infected cells and supernatants and also in mouse pneumocytes under TEM. The viruses are round with diameters 80～120nm.The isolated coronavirus was associated with the current SARS epidemics.

Objective To determine the causative association between a newly isolated coronavirus and the current epidemic of severe acute respiratory syndrome (SARS) Methods Coronavirus was isolated from the samples of patients with SARS by cell culture Immunofluorescence assay and neutralization test were used to detect the antibodies in serum of SARS patients against newly isolated coronavirus, in order to analyze and determine the association between coronavirus and SARS pathogen Results The antibodies against the novel coronavirus could be detected in 99 of 113 sera from clinically diagnosed SARS patients The results of 10 pairs of double serum detection showed that, antibody titers in the late phase were significantly higher than those in the acute phase, and a highest increase by 128 folds was being found. The neutralization test showed that the antibodies from SARS patients' sera could neutralize the novel coronavirus Conclusion The newly isolated coronavirus was closely associated with and possibly the key pathogen of SARS

Enterovirus 71 (EV71) is one of the primary causative agents of hand, foot and mouth disease in children and closely associated with severe neurological complications and even deaths.EV71 outbreaks have occurred throughout the Asia-Pacific region since 1990s, posing global public health threat;however, no specific therapeutic strategy exists for severe EV71 infection.Several inactivated vaccine products have entered or finished the clinical trial stage, and some novel vaccine candidates, including live attenuated, subunit, and virus-like particle, show great potential for further develop-ment.This review summarizes the present situation and progress in the development of EV71 vaccines.

Objective:To establish fusion PCR for amplification of the full-length cDNA of dengue virus type 2. Methods:According to the published nucleotide sequence of D2-43,the primers were devised and the 5′ and 3′ half genomic cDNAs of dengue virus type 2 were amplified by long reverse transcription PCR. Using the PCR products as model,the approximate 11 kb full-length cDNA was amplified by fusion PCR. The sequence containing the 5′ noncoding region was determined by PRISMTM ABI 377 automated sequencer.Results:Using fusion PCR,the full-length cDNA of dengue virus type 2 was successfully amplified and its correctness was proved by partial nucleotide sequences analysis. To our best knowledge, this is the first report of the same kind.Conclusion:Fusion PCR is an effective method to amplify the genomic cDNA of dengue virus.

Influenza, caused by influenza virus, is a serious respiratory illness which poses a global public health threat. Vaccination is the primary strategy for the prevention and control of influenza. Although both inactivated vaccines and the live attenuated vaccines are effective in preventing influenza, the current vaccines have poor efficacy in the elderly and fail to provide protection against heterosubtype viruses. Development of a safer and more effective influenza vaccine that provides broad cross protection, overcoming the intrinsic limitation of the current vaccines, has been a scientific challenge. During the past decades, structural biology, reverse genetic and other virological technologies developed quickly and sped the progress of influenza vaccinology. Some new strategies for developing influenza vaccine have been generated, produced encouraging results, which showed great prospect as next-generation of influenza vaccines.
Disease Outbreaks ; prevention & control ; Hemagglutinin Glycoproteins, Influenza Virus ; immunology ; Humans ; Influenza Vaccines ; biosynthesis ; immunology ; Influenza, Human ; immunology ; prevention & control ; virology ; Orthomyxoviridae ; immunology ; Vaccines, Attenuated ; immunology ; Vaccines, Inactivated ; immunology

Hand-foot-mouth disease (HFMD) is an acute infectious disease caused by various enteroviruses. Recently, large HFMD outbreaks caused by enterovirus type 71 (EV71) have been frequently reported in China, posing great threats on children's health. There is no specific antiviral therapy for severe HFMD, and patient management mainly depends on supportive and symptomatic treatment. Intravenous immunoglobulin (IVIG) is a pharmaceutical preparation of human IgG that is pooled from thousands of healthy blood donors, and contained neutralization antibodies against various enteroviruses, including EV71. IVIG therapy should be carefully administrated for severe HFMD considering its role on passive immunization against EV71 and immune regulation.
Antibodies, Neutralizing ; immunology ; therapeutic use ; Antibodies, Viral ; immunology ; therapeutic use ; Enterovirus A, Human ; immunology ; Hand, Foot and Mouth Disease ; therapy ; virology ; Humans ; Immunization, Passive ; Immunoglobulins, Intravenous ; immunology ; therapeutic use