General guidance and sample information is provided for reference and. Pandemic influenza continuity of operations annex template. This study represents the first time a wildtype influenza virus challenge of healthy human volunteers has been performed using a reverse geneticsproduced virus under an ind, and serves as a standardized model for future healthy volunteer challenge studies with ah1n1pdm09 and other wildtype circulating influenza strains. Viral recognition by pbmcs will be assessed by measuring secretion of inflammatory cytokines and other inflammatory mediators using techniques such as multiplex elisa. A sectioned version and a closed version of the virus are included. Although the provisionally named influenza d virus was first isolated as an influenza c like virus from pigs with respiratory illness in oklahoma in 2011 1,2, epidemiologic. The influenza virion measures about 80120 nm in diameter. The tree shrew is a promising model for the study of influenza b virus infection. Determine which if any animal model provides the best information on cross. The united states is not currently experiencing an influenza pandemic. The viruss shape is determined by a layer of matrix protein underneath the influenza membrane. Optimal control of influenza epidemic model with virus mutations.
These three proteins are involved in virus docking, endocytosis and fusion. Influenza, known as the flu, is a highly contagious respiratory virus. Modeling human influenza infection in the laboratory ncbi nih. Influenza viruses are orthomyxoviruses that cause acute.
This will ensure that the risk assessment is informed by the latest and most comprehensive information available about the virus, the extent of its circulation in animals and the number and severity of human infections. Pdf optimal control of influenza epidemic model with virus. A mathematical model for the global spread of influenza. Listing a study does not mean it has been evaluated by the u. The mechanisms underlying influenza virus spread are poorly understood, in part because of the lack of a convenient animal model to study this phenomenon. A computational approach for predicting the future evolution of the human influenza virus, based on populationgenetic data of previous strains, is presented. Ferrets and humans share similarities in lung physiology, cellular receptor distribution, and clinical signs of infection, making the ferret an attractive small mammalian model for laboratory study of influenza viruses 1. Research open access the tree shrew provides a useful alternative model for the study of influenza h1n1 virus zifeng yang1,2, jin zhao1, yutong zhu3, yutao wang1, rong liu1, suishan zhao1, runfeng li1. Some isolates of influenza a virus cause severe disease both in domestic poultry and, rarely, in humans. Influenza, influenzaassociated mortality, and novel. Ferrets as models for influenza virus transmission studies. Influenza b virus is one of two types of influenza virus that cause substantial morbidity and mortality in humans, the other being influenza a virus. Strategies for mitigating an influenza pandemic nature.
Mitigating the impact of pandemic influenza through. A mathematical model for the global spread of influenza leonid a. Rvachev gamaleya institute of epidemioloxy and microbiology, academy of medical sciences, moscow, u. The influenza a and b viruses that routinely spread in people human influenza viruses are responsible for seasonal flu epidemics each year. Influenza a virus infections are widespread in swine herds across the world. Statistical errors of predicted and posterior wrightian fitness.
The virus is transmitted to people from wild animals and spreads in the human population through humantohuman transmission. Influenza in humans is often referred to as the seasonal flu. Influenza in birds is often referred to as avian influenza, in pigs as swine influenza, in horses as equine influenza and so on. Assessing spread of influenza under different epidemiological settings 3. Seasonality of influenza virus infection and implications for global virus spread 3. These symptoms typically begin two days after exposure to the virus and most last less than a week. Influenza is an rna virus with a roughly spherical lipid envelope, which is colored yellow on our schematic model. Apr 26, 2006 a populationdynamic model for evaluating the potential spread of drugresistant influenza virus infections during communitybased use of antivirals. Murine model for the study of influenza d virus request pdf. Characteristics of the emergent influenza a h1n1 viruses. Influenza diagnosis clinical and epidemiological characteristics increase of febrile respiratory illness lab isolation of influenza virus from clinical specimen e. Research open access the tree shrew provides a useful. Validation of the wildtype influenza a human challenge model. Guidance has been developed to prepare, plan, and practice for the next influenza flu pandemic.
Activity of the novel influenza a h1n1, marchmay 2009 between march and 26 may 2009, novel influenza a h1n1 virus infections have been. Antibodydependent enhancement of influenza disease promoted. Although influenza virus was recognized as an important pathogen over a century ago, influenza continues to cause a significant burden of disease. Predicting hotspots for influenza virus reassortment. Selection pressures and evolutionary constraints on influenza viruses. In spite of the significant advances in our knowledge of iav infections, holistic. Jul 23, 2019 nonneutralizing antibodies have the potential to mediate enhancement of respiratory disease erd. The last pandemic influenza plan for the department of health and human services update was issued in 2009. Nonneutralizing antibodies have the potential to mediate enhancement of respiratory disease erd. Mitigating the impact of pandemic influenza through vaccine. The emergence of drug resistance has been a major challenge in curbing the spread of influenza.
The pandemic risk assessment model pram is a mathematical model developed to analyse two pandemic influenza control measures available to public health. Dec 20, 2006 novel influenza virus strains can be the source of infrequent but devastating pandemics, most famously the 1918 pandemic, which killed between 20 and 40 million people. Full text modeling human influenza infection in the laboratory idr. The tree shrew is a promising model for the study of. It is an orthomyxovirus that contains the glycoproteins haemagglutinin and neuraminidase. Influenza, influenzaassociated mortality, and novel influenza a. Metapopulation model using commuting flow for national spread. A manual for estimating disease burden associated with seasonal influenza.
Influenza a viruses can be broken down into subtypes depending on the genes that make up the surface proteins. Influenza a viruses iavs infect a variety of hosts, including humans, swine, and various avian species. The render settings and materials are included in the max 9. The geometry resolution of the model is suitable for close up and renderings in print resolution. How cdc estimates the burden of seasonal influenza in the. Cea mitigating the impact of pandemic influenza through vaccine innovation. Pdf influenza is a human pathogen that continues to pose a public health threat. The spatialtemporal model for the nationwide influenza epidemic is also presented in this section. Once a novel virus has been identified by cdc, confirmation may be made by public health laboratories following cdcapproved protocols for that specific virus, or by laboratories using an fdaauthorized test specific for detection of that novel influenza virus. Pr8 h1n1 influenza virus injected into the ovarian bursa of balbc mice grew well, with peak titers between days 3 and 5.
A populationdynamic model for evaluating the potential spread of drugresistant influenza virus infections during communitybased use of antivirals. Those interactions probably impact the microorganisms transmission dynamics and the influenza. Influenza virus in humans and domestic animals could reassort and cause another pandemic. The severity of epidemic and pandemic influenza outbreaks is dictated in part by the efficiency with which the causative strain transmits between human hosts. Oct 12, 2015 influenza a virus iav infection represents a global threat causing seasonal outbreaks and pandemics. During the pandemic of 19181919, influenza a virus iav caused as many as 50100 million deaths. Request pdf murine model for the study of influenza d virus a novel genus within the orthomyxoviridae family was identified in the usa and named influenza d virus idv.
In this study, we develop mathematical models based on experimental data, representing. Influenza research at the human and animal interface world health. The susceptibility of ferrets to influenza virus infection has been known for nearly a century. This work is licensed under a creative commons attribution. The membrane contains two types of surface proteins and a number of protein channels. Novel influenza virus strains can be the source of infrequent but devastating pandemics, most famously the 1918 pandemic, which killed between 20 and 40 million people.
The flu is a type of germ called a virus that you breathe in. Pigs should be considered a suitable and valuable model for influenza a virus infection, in regards to pathogenesis, transmission, and immune response to infection or vaccines. Aug 27, 2014 influenza a virus infections are widespread in swine herds across the world. In section 3, the simulation results for transmission dynamics of the 2009 h1n1 influenza virus in the entire country are discussed. To identify geographic areas where agricultural production systems are conducive to reassortment, we fitted multivariate regression models to surveillance data on influenza a virus subtype h5n1 among poultry in china and egypt and subtype h3n2 among humans.
Mar 24, 2012 highly detailed influenza virus model. Since that time, our nation has experienced, and learned from, the 2009 influenza ah1n1 pandemic and the emergence of other influenza viruses of concern, such as h7n9 that emerged in 20 in china and continues to cause periodic outbreaks. Enhance your virus lesson with our influenza virus capsule. Indeed, despite extremely efficient transmission among humans and virulence. Influenza b virus is a main causative pathogen of annual influenza epidemics, however, research on influenza b virus in general lags behind that on influenza a viruses, one of the important reasons is studies on influenza b viruses in animal models are limited. Influenza b virus is a main causative pathogen of annual influenza epidemics, however, research on influenza b virus in general lags behind that on influenza a viruses, one of the important reasons is studies. The virus infects the human respiratory tract where other species of bacteria or viruses cohabit. It comprises key steps of their replication, from virus entry to budding. Efficacy of fluv in an h1n1 influenza human challenge model. Validation of the wildtype influenza a human challenge. Interaction among influenza viruses ah1n1, ah3n2, and b. This model simulates the transmission and perpetuation of a virus in a human population. Influenza, commonly known as the flu, is an infectious disease caused by an influenza virus. Autoplay when autoplay is enabled, a suggested video will automatically play next.
Pandemic influenza plan centers for disease control and. The outside of the virus capsule is covered with three specific proteins. The first part of this work covers a model for the intracellular life cycle of influenza a viruses. These symptoms typically begin two days after exposure to the virus and most last. Swine as a model for influenza a virus infection and immunity. Hemagglutinin purple, neuraminidase pink and the m2 channel blue. Every year, influenza causes high morbidity and mortality especially among the immunocompromised persons worldwide. Ecological biologists have suggested a number of factors which may influence the survival of a directly transmitted virus within a population. Birds, pigs, horses, ferrets, dogs, and cats can all be infected with various strains of the influenza virus. Currently there is no licensed treatment or vaccine for the ebola virus.
The guinea pig as a transmission model for human influenza. More routinely, influenza virus also generates epidemics or large outbreaks. Jun 08, 2017 efficacy of fluv in an h1n1 influenza human challenge model the safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Antibodydependent enhancement of influenza disease. It typically spreads through respiratory droplets when a person. An agentbased model simulation of influenza interactions at. Mathematical models have been designed to enable public health officials, policymakers, and students of infectious disease to examine. Although the exact biological mechanisms involved remain unelucidated, secondary bacterial infections are known to account for a large part of the influenzaassociated burden, during seasonal and pandemic outbreaks. Among others, mice, ferrets, pigs, and nonhuman primates have been used to study influenza virus infection in vivo, as well as to do pre clinical. The inability to provide lasting protection to humans against influenza b virus infection is due, in. Influenza a virus causes influenza in birds and some mammals, and is the only species of the genus alphainfluenzavirus of the virus family orthomyxoviridae. Influenza negatively affects swine health and production, and represents a significant threat to public health due to the risk of zoonotic infections. Our study describes ade with two different functional mabs that destabilized ha stem domain, increased influenza virus fusion kinetics, and led to enhanced lung pathology and erd in a dosedependent manner in a mice model. An agentbased model simulation of influenza interactions.
Mathematical analysis of influenza a dynamics in the. Here we investigated the tree shrew as a potential model for influenza b virus studies. Influenza a virus iav infection represents a global threat causing seasonal outbreaks and pandemics. There are many different strains types of this virus. These pandemics are associated with major shifts in the ha and na proteins that define viral strains. In this paper, a mathematical model is formulated and used to analyze the transmission dynamics of influenza a virus having incorporated the aspect of drug resistance. May 19, 2015 more importantly, swine are genetically and physiologically closely related to humans, and show similar clinical signs and pathology upon iav infection. Nevertheless, to capture the dynamic behaviour of an influenza pandemic we need an economic model that is also dynamic. Research open access the tree shrew provides a useful alternative model for the study of influenza h1n1 virus zifeng yang1,2, jin zhao1, yutong zhu3, yutao wang1, rong liu1, suishan zhao1, runfeng li1, chunguang yang1, jiqiang li4 and nanshan zhong1 abstract.
Strains of all subtypes of influenza a virus have been isolated from wild birds, although disease is uncommon. Pdf homology model of the structure of influenza b virus. Utility and timing of different response strategies during early spread of human cases of an animal or pandemic influenza virus. Influenza is a respiratory virus that imposes a heavy burden on human populations by causing millions of severe illness cases and deaths worldwide every year, despite the development of public health policies to limit its propagation. The use of small mammalian models has become indispensable for. Dynamics of virus spread at global and local levels 3. Further, the model must be able to capture the short, sharp duration of influenza pandemics. In the united states alone, its estimated that in the 20172018 season there were 959,000 hospitalizations related to influenza illness, and 79,400 deaths cdc, 2018. Optimal control of influenza epidemic model with virus. Additionally, secondary bacterial infections, caused mainly by streptococcus pneumoniae, are one of the main complications and responsible for the enhanced morbidity and mortality associated with iav infections. Swine herds can act as reservoirs for potentially pandemic influenza strains. All strains are named starting with an a or b type such as influenza a h1n1 or influenza. The two temperaturesensltlve ts lesions present in influenza ahong kong68ts 1e h3n268 virus were transferred via genetic reassortment to influenza ageorgia74 h3n274 wildtype virus. Because of its clinical importance, many investigators use animal models to understand the biologic mechanisms of influenza a virus.
Although several avian influenza viruses were considered, emphasis was. Influenza virus capsule model 3d molecular designs. The effects of the nonpharmaceutical interventions based on the centrality analysis are discussed in this section. Pandemic influenza continuity template guide instructions this template provides guidance to assist organizations in developing a pandemic influenza continuity of operations plan or, if the organization already has a continuity plan, a pandemic influenza annex. Influenza virus, although not a normal pathogen of the reproductive tract, was used to develop a model for the investigation of mucosal immunity in the uterus. Hostlevel influenza virusrespiratory pathogen interactions are often reported. In virology, influenza a virus subtype h1n1 ah1n1 is the subtype of influenza a virus that was the most common cause of human influenza flu in 2009, and is associated with the 1918 spanish flu outbreak. Additionally, secondary bacterial infections, caused mainly by streptococcus pneumoniae, are one of the main complications and responsible for the enhanced. Pdf mathematical models of influenza a virus infection. Mathematical modeling of influenza a virus dynamics within. Pdf the ferret as a model organism to study influenza a virus.
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