Yunzhi Liu

Integrated Global System Model for Climate Policy Assessment: Feedbacks and Sensitivity Studies

Alternative policies to address global climate change are being debated in many nations and within the United Nations Framework Convention on Climate Change. To help provide objective and comprehensive analyses in support of this process, we have developed a model of the global climate system consisting of coupled sub-models of economic growth and associated emissions, natural fluxes, atmospheric chemistry, climate, and natural terrestrial ecosystems. The framework of this Integrated Global System Model is described and the results of sample runs and a sensitivity analysis are presented. This multi-component model addresses most of the major anthropogenic and natural processes involved in climate change and also is computationally efficient. As such, it can be used effectively to study parametric and structural uncertainty and to analyze the costs and impacts of many policy alternatives. Initial runs of the model have helped to define and quantify a number of feedbacks among the sub-models, and to elucidate the geographical variations in several variables that are relevant to climate science and policy. The effect of changes in climate and atmospheric carbon dioxide levels on the uptake of carbon and emissions of methane and nitrous oxide by land ecosystems is one potentially important feedback which has been identified. The sensitivity analysis has enabled preliminary assessment of the effects of uncertainty in the economic, atmospheric chemistry, and climate sub-models as they influence critical model results such as predictions of temperature, sea level, rainfall, and ecosystem productivity. We conclude that uncertainty regarding economic growth, technological change, deep oceanic circulation, aerosol radiative forcing, and cloud processes are important influences on these outputs.

Correlation analysis of EV71 detection and case severity in hand, foot, and mouth disease in the Hunan Province of China.

An increase in the incidence of hand, foot and mouth disease (HFMD) cases has been observed in the Hunan province of mainland China since 2009 with a particularly higher level of severe cases in 2010–2012. Intestinal viruses of the picornaviridae family are responsible for the human syndrome associated with HFMD with enterovirus 71 (EV71) and Coxsackievirus A16 (Cox A16) being the most common causative strains. HFMD cases associated with EV71 are generally more severe with an increased association of morbidity and mortality. In this study, the etiology surveillance data of HFMD cases in Hunan province from March 2010 to October 2012 were analyzed to determine if there is a statistically relevant linear correlation exists between the detection rate of EV71 in mild cases and the proportion of severe cases among all HFMD patients. As the cases progressed from mild to severe to fatal, the likelihood of EV71 detection increased (25.78%, 52.20% and 84.18%, respectively). For all cases in the timeframe evaluated in this study, the presence of virus was detected in 63.21% of cases; among cases showing positivity for virus, EV71 infection accounted for 50.14%. These results provide evidence to support the observed higher morbidity and mortality associated with this outbreak and emphasizes the importance of early detection in order to implement necessary prevention measures to mitigate disease progression.

Investigation of Avian Influenza Infections in Wild Birds, Poultry and Humans in Eastern Dongting Lake, China

We investigated avian influenza infections in wild birds, poultry, and humans at Eastern Dongting Lake, China. We analyzed 6,621 environmental samples, including fresh fecal and water samples, from wild birds and domestic ducks that were collected from the Eastern Dongting Lake area from November 2011 to April 2012. We also conducted two cross-sectional serological studies in November 2011 and April 2012, with 1,050 serum samples collected from people exposed to wild birds and/or domestic ducks. Environmental samples were tested for the presence of avian influenza virus (AIV) using quantitative PCR assays and virus isolation techniques. Hemagglutination inhibition assays were used to detect antibodies against AIV H5N1, and microneutralization assays were used to confirm these results. Among the environmental samples from wild birds and domestic ducks, AIV prevalence was 5.19 and 5.32%, respectively. We isolated 39 and 5 AIVs from the fecal samples of wild birds and domestic ducks, respectively. Our analysis indicated 12 subtypes of AIV were present, suggesting that wild birds in the Eastern Dongting Lake area carried a diverse array of AIVs with low pathogenicity. We were unable to detect any antibodies against AIV H5N1 in humans, suggesting that human infection with H5N1 was rare in this region.

Molecular Characteristics and Phylogenetic Analysis of N Gene of Human Derived Rabies Virus

OBJECTIVE To investigate the relationship between the molecular characteristics and phylogenetic evolution of rabies N gene. METHODS Saliva samples were collected from rabies cases, and RT-PCR was used to amplify the N gene of rabies virus with the specific primers. The amplifying product of RT-PCR was cloned to pUCm-T vector and transformed into E.coli XL1-Blue and then the blue-white selection, PCR screening and gene sequencing were carried out to identify the positive clones. Finally, ExPASy and other bioinformatics software were used to analyze and predict the structure and biological characteristics of the N genome. RESULTS The amplification product of RT-PCR was 1 353 bp, the recombinant plasmid pUCm-T/N was constructed, the whole length of the N gene open reading frame was composed of 1 353 nucleotide residues to code 450 amino acids (20 kinds), the accession number submitted to the Genbank was HM756692, its sequence homology of nucleotides and amino acids compared with the vaccine strain CTN-1-V was 90% and 99% respectively. The evolutionary analysis showed that the isolated strain belonged to genotype I with certain geographic regionality. CONCLUSION The characteristics investigation and bioinformatics analysis of Hunan0806 N gene will provide fundamental data to reveal the significance of the N gene characteristics for rabies epidemiology and its prevention & control.

Complete Genome Sequence of an H12N8 Avian Influenza Virus Isolated from Wild Bird Feces in Hunan East Dongting Lake National Nature Reserve

ABSTRACT An H12N8 subtype avian influenza virus (AIV) was isolated from a wild bird in China in 2011. It is the first report of isolation of the H12N8 subtype AIV in Asia. Phylogenetic analysis results suggested it is a reassortant, and all eight gene segments belong to the Eurasian gene pool.

Epidemic of rabies and effect of its vaccine against a dog that consecutively attacked ten people in one day.

doi: 10.3967/ bes2014.017 1. Hunan Center for Disease Control and Prevention, Key Laboratory of Microbial Molecular Biology of Hunan Province, Changsha 410005, Hunan, China; 2. Key Laboratory for Medical Virology, Ministry of Health, Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, China; 3. Yongzhou Center for Disease Control and Prevention, Yongzhou 425000, Hunan, China; 4. Ningyuan Center for Disease Control and Prevention, Yongzhou 425600, Hunan, China Letter to the Editor