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2.
Trends Microbiol ; 29(7): 573-581, 2021 07.
Article in English | MEDLINE | ID: covidwho-1130313

ABSTRACT

Emerging zoonotic diseases exert a significant burden on human health and have considerable socioeconomic impact worldwide. In Asia, live animals as well as animal products are commonly sold in informal markets. The interaction of humans, live domestic animals for sale, food products, and wild and scavenging animals, creates a risk for emerging infectious diseases. Such markets have been in the spotlight as sources of zoonotic viruses, for example, avian influenza viruses and coronaviruses, Here, we bring data together on the global impact of live and wet markets on the emergence of zoonotic diseases. We discuss how benefits can be maximized and risks minimized and conclude that current regulations should be implemented or revised, to mitigate the risk of new diseases emerging in the future.


Subject(s)
Commerce/standards , Communicable Diseases, Emerging/etiology , Food , Orthomyxoviridae Infections/transmission , Zoonoses/transmission , Animals , Asia , Birds/virology , COVID-19/transmission , COVID-19/virology , Commerce/legislation & jurisprudence , Commerce/methods , Communicable Diseases, Emerging/prevention & control , Communicable Diseases, Emerging/virology , Crowding , Humans , Influenza in Birds/transmission , Influenza in Birds/virology , Influenza, Human/virology , Orthomyxoviridae Infections/virology , Zoonoses/classification , Zoonoses/virology
3.
J Biol Chem ; 296: 100017, 2021.
Article in English | MEDLINE | ID: covidwho-910220

ABSTRACT

Through annual epidemics and global pandemics, influenza A viruses (IAVs) remain a significant threat to human health as the leading cause of severe respiratory disease. Within the last century, four global pandemics have resulted from the introduction of novel IAVs into humans, with components of each originating from avian viruses. IAVs infect many avian species wherein they maintain a diverse natural reservoir, posing a risk to humans through the occasional emergence of novel strains with enhanced zoonotic potential. One natural barrier for transmission of avian IAVs into humans is the specificity of the receptor-binding protein, hemagglutinin (HA), which recognizes sialic-acid-containing glycans on host cells. HAs from human IAVs exhibit "human-type" receptor specificity, binding exclusively to glycans on cells lining the human airway where terminal sialic acids are attached in the α2-6 configuration (NeuAcα2-6Gal). In contrast, HAs from avian viruses exhibit specificity for "avian-type" α2-3-linked (NeuAcα2-3Gal) receptors and thus require adaptive mutations to bind human-type receptors. Since all human IAV pandemics can be traced to avian origins, there remains ever-present concern over emerging IAVs with human-adaptive potential that might lead to the next pandemic. This concern has been brought into focus through emergence of SARS-CoV-2, aligning both scientific and public attention to the threat of novel respiratory viruses from animal sources. In this review, we summarize receptor-binding adaptations underlying the emergence of all prior IAV pandemics in humans, maintenance and evolution of human-type receptor specificity in subsequent seasonal IAVs, and potential for future human-type receptor adaptation in novel avian HAs.


Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Influenza A virus/metabolism , Influenza in Birds/epidemiology , Influenza, Human/epidemiology , Pandemics , Polysaccharides/chemistry , Receptors, Virus/metabolism , Adaptation, Physiological , Animals , Binding Sites , Biological Coevolution , Birds/virology , Hemagglutinin Glycoproteins, Influenza Virus/chemistry , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Humans , Influenza A virus/chemistry , Influenza A virus/genetics , Influenza in Birds/transmission , Influenza in Birds/virology , Influenza, Human/transmission , Influenza, Human/virology , Models, Molecular , Polysaccharides/metabolism , Protein Binding , Receptors, Virus/chemistry , Receptors, Virus/genetics , Respiratory System/virology , Sialic Acids/chemistry , Sialic Acids/metabolism , Species Specificity
4.
Front Immunol ; 11: 552909, 2020.
Article in English | MEDLINE | ID: covidwho-803900

ABSTRACT

The 2019 novel coronavirus (SARS-CoV-2) pandemic has caused a global health emergency. The outbreak of this virus has raised a number of questions: What is SARS-CoV-2? How transmissible is SARS-CoV-2? How severely affected are patients infected with SARS-CoV-2? What are the risk factors for viral infection? What are the differences between this novel coronavirus and other coronaviruses? To answer these questions, we performed a comparative study of four pathogenic viruses that primarily attack the respiratory system and may cause death, namely, SARS-CoV-2, severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV), and influenza A viruses (H1N1 and H3N2 strains). This comparative study provides a critical evaluation of the origin, genomic features, transmission, and pathogenicity of these viruses. Because the coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 is ongoing, this evaluation may inform public health administrators and medical experts to aid in curbing the pandemic's progression.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/epidemiology , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H3N2 Subtype/genetics , Influenza, Human/epidemiology , Middle East Respiratory Syndrome Coronavirus/genetics , Pneumonia, Viral/epidemiology , SARS Virus/genetics , Severe Acute Respiratory Syndrome/epidemiology , Animals , Betacoronavirus/pathogenicity , Birds/virology , COVID-19 , Coronavirus Infections/transmission , Coronavirus Infections/virology , Genome, Viral , Humans , Influenza A Virus, H1N1 Subtype/pathogenicity , Influenza A Virus, H3N2 Subtype/pathogenicity , Influenza in Birds/epidemiology , Influenza in Birds/transmission , Influenza in Birds/virology , Influenza, Human/transmission , Influenza, Human/virology , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Pandemics , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , SARS Virus/pathogenicity , SARS-CoV-2 , Severe Acute Respiratory Syndrome/transmission , Severe Acute Respiratory Syndrome/virology , Virulence/immunology
5.
J Neuropathol Exp Neurol ; 79(8): 823-842, 2020 08 01.
Article in English | MEDLINE | ID: covidwho-639090

ABSTRACT

Biological evolution of the microbiome continually drives the emergence of human viral pathogens, a subset of which attack the nervous system. The sheer number of pathogens that have appeared, along with their abundance in the environment, demand our attention. For the most part, our innate and adaptive immune systems have successfully protected us from infection; however, in the past 5 decades, through pathogen mutation and ecosystem disruption, a dozen viruses emerged to cause significant neurologic disease. Most of these pathogens have come from sylvatic reservoirs having made the energetically difficult, and fortuitously rare, jump into humans. But the human microbiome is also replete with agents already adapted to the host that need only minor mutations to create neurotropic/toxic agents. While each host/virus symbiosis is unique, this review examines virologic and immunologic principles that govern the pathogenesis of different viral CNS infections that were described in the past 50 years (Influenza, West Nile Virus, Zika, Rift Valley Fever Virus, Hendra/Nipah, Enterovirus-A71/-D68, Human parechovirus, HIV, and SARS-CoV). Knowledge of these pathogens provides us the opportunity to respond and mitigate infection while at the same time prepare for inevitable arrival of unknown agents.


Subject(s)
Central Nervous System Viral Diseases/epidemiology , Central Nervous System Viral Diseases/transmission , Zoonoses/epidemiology , Zoonoses/transmission , Animals , Birds , Central Nervous System Viral Diseases/prevention & control , Ecosystem , Humans , Influenza in Birds/epidemiology , Influenza in Birds/prevention & control , Influenza in Birds/transmission , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Influenza, Human/transmission , West Nile Fever/epidemiology , West Nile Fever/prevention & control , West Nile Fever/transmission , Zika Virus Infection/epidemiology , Zika Virus Infection/prevention & control , Zika Virus Infection/transmission , Zoonoses/prevention & control
6.
BMC Infect Dis ; 20(1): 369, 2020 May 24.
Article in English | MEDLINE | ID: covidwho-343360

ABSTRACT

BACKGROUND: Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. METHOD: Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013 to 2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) model to select and quantify the dominant factor of H7N9 infection. RESULTS: All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80 to 0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p > 0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR = 0.35). Shenzhen implemented partial closure for first 3 epidemics (p > 0.05) and all closure in the latest 2 epidemic waves (RRR = 0.64). CONCLUSION: Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and rural remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure seems greater than that of meteorology on H7N9 transmission.


Subject(s)
Epidemics/prevention & control , Influenza A Virus, H7N9 Subtype , Influenza in Birds/epidemiology , Influenza in Birds/transmission , Influenza, Human/epidemiology , Poultry/virology , Animals , China/epidemiology , Cities/epidemiology , Humans , Humidity , Incidence , Influenza in Birds/virology , Influenza, Human/virology , Linear Models , Poisson Distribution , Risk Factors , Temperature , Urban Population
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