Pandemics: Epidemics of infectious disease that have spread to many countries, often more than one continent, and usually affecting a large number of people.Influenza A Virus, H1N1 Subtype: A subtype of INFLUENZA A VIRUS with the surface proteins hemagglutinin 1 and neuraminidase 1. The H1N1 subtype was responsible for the Spanish flu pandemic of 1918.Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Influenza Vaccines: Vaccines used to prevent infection by viruses in the family ORTHOMYXOVIRIDAE. It includes both killed and attenuated vaccines. The composition of the vaccines is changed each year in response to antigenic shifts and changes in prevalence of influenza virus strains. The vaccine is usually bivalent or trivalent, containing one or two INFLUENZAVIRUS A strains and one INFLUENZAVIRUS B strain.Oseltamivir: An acetamido cyclohexene that is a structural homolog of SIALIC ACID and inhibits NEURAMINIDASE.Orthomyxoviridae Infections: Virus diseases caused by the ORTHOMYXOVIRIDAE.Influenza A Virus, H5N1 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 5 and neuraminidase 1. The H5N1 subtype, frequently referred to as the bird flu virus, is endemic in wild birds and very contagious among both domestic (POULTRY) and wild birds. It does not usually infect humans, but some cases have been reported.Quarantine: Restriction of freedom of movement of individuals who have been exposed to infectious or communicable disease in order to prevent its spread; a period of detention of vessels, vehicles, or travelers coming from infected or suspected places; and detention or isolation on account of suspected contagion. It includes government regulations on the detention of animals at frontiers or ports of entrance for the prevention of infectious disease, through a period of isolation before being allowed to enter a country. (From Dorland, 28th ed & Black's Veterinary Dictionary, 17th ed)Disaster Planning: Procedures outlined for the care of casualties and the maintenance of services in disasters.Hemagglutinin Glycoproteins, Influenza Virus: Membrane glycoproteins from influenza viruses which are involved in hemagglutination, virus attachment, and envelope fusion. Fourteen distinct subtypes of HA glycoproteins and nine of NA glycoproteins have been identified from INFLUENZA A VIRUS; no subtypes have been identified for Influenza B or Influenza C viruses.Reassortant Viruses: Viruses containing two or more pieces of nucleic acid (segmented genome) from different parents. Such viruses are produced in cells coinfected with different strains of a given virus.Influenza A Virus, H3N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 3 and neuraminidase 2. The H3N2 subtype was responsible for the Hong Kong flu pandemic of 1968.Influenza in Birds: Infection of domestic and wild fowl and other BIRDS with INFLUENZA A VIRUS. Avian influenza usually does not sicken birds, but can be highly pathogenic and fatal in domestic POULTRY.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Ferrets: Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.Influenza A Virus, H2N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 2 and neuraminidase 2. The H2N2 subtype was responsible for the Asian flu pandemic of 1957.Neuraminidase: An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)Antiviral Agents: Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.Influenza A virus: The type species of the genus INFLUENZAVIRUS A that causes influenza and other diseases in humans and animals. Antigenic variation occurs frequently between strains, allowing classification into subtypes and variants. Transmission is usually by aerosol (human and most non-aquatic hosts) or waterborne (ducks). Infected birds shed the virus in their saliva, nasal secretions, and feces.History, 20th Century: Time period from 1901 through 2000 of the common era.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.Basic Reproduction Number: The expected number of new cases of an infection caused by an infected individual, in a population consisting of susceptible contacts only.Cross Protection: Protection conferred on a host by inoculation with one strain or component of a microorganism that prevents infection when later challenged with a similar strain. Most commonly the microorganism is a virus.Hemagglutination Inhibition Tests: Serologic tests in which a known quantity of antigen is added to the serum prior to the addition of a red cell suspension. Reaction result is expressed as the smallest amount of antigen which causes complete inhibition of hemagglutination.Vibrio parahaemolyticus: A species of bacteria found in the marine environment, sea foods, and the feces of patients with acute enteritis.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Communicable Disease Control: Programs of surveillance designed to prevent the transmission of disease by any means from person to person or from animal to man.Vaccination: Administration of vaccines to stimulate the host's immune response. This includes any preparation intended for active immunological prophylaxis.Vibrio Infections: Infections with bacteria of the genus VIBRIO.Mass Vaccination: Administration of a vaccine to large populations in order to elicit IMMUNITY.Influenza A Virus, H9N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 9 and neuraminidase 2. The H9N2 subtype usually infects domestic birds (POULTRY) but there have been some human infections reported.Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Orthomyxoviridae: A family of RNA viruses causing INFLUENZA and other diseases. There are five recognized genera: INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; ISAVIRUS; and THOGOTOVIRUS.Influenza A Virus, H1N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 1 and neuraminidase 2. It is endemic in both human and pig populations.Sentinel Surveillance: Monitoring of rate of occurrence of specific conditions to assess the stability or change in health levels of a population. It is also the study of disease rates in a specific cohort such as in a geographic area or population subgroup to estimate trends in a larger population. (From Last, Dictionary of Epidemiology, 2d ed)Health Planning: Planning for needed health and/or welfare services and facilities.Polysorbates: Sorbitan mono-9-octadecanoate poly(oxy-1,2-ethanediyl) derivatives; complex mixtures of polyoxyethylene ethers used as emulsifiers or dispersing agents in pharmaceuticals.Zanamivir: A guanido-neuraminic acid that is used to inhibit NEURAMINIDASE.World Health: The concept pertaining to the health status of inhabitants of the world.Pneumonia, Viral: Inflammation of the lung parenchyma that is caused by a viral infection.SqualeneHospitalization: The confinement of a patient in a hospital.Civil Defense: Preventive emergency measures and programs designed to protect the individual or community in times of hostile attack.Disease Transmission, Infectious: The transmission of infectious disease or pathogens. When transmission is within the same species, the mode can be horizontal or vertical (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Vaccines, Inactivated: Vaccines in which the infectious microbial nucleic acid components have been destroyed by chemical or physical treatment (e.g., formalin, beta-propiolactone, gamma radiation) without affecting the antigenicity or immunogenicity of the viral coat or bacterial outer membrane proteins.History, 21st Century: Time period from 2001 through 2100 of the common era.Communicable Diseases, Emerging: Infectious diseases that are novel in their outbreak ranges (geographic and host) or transmission mode.Zoonoses: Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.World War I: Global conflict primarily fought on European continent, that occurred between 1914 and 1918.Antibodies, Neutralizing: Antibodies that reduce or abolish some biological activity of a soluble antigen or infectious agent, usually a virus.Virus Shedding: The expelling of virus particles from the body. Important routes include the respiratory tract, genital tract, and intestinal tract. Virus shedding is an important means of vertical transmission (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).Cholera: An acute diarrheal disease endemic in India and Southeast Asia whose causative agent is VIBRIO CHOLERAE. This condition can lead to severe dehydration in a matter of hours unless quickly treated.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Public Health: Branch of medicine concerned with the prevention and control of disease and disability, and the promotion of physical and mental health of the population on the international, national, state, or municipal level.Travel: Aspects of health and disease related to travel.Hong Kong: The former British crown colony located off the southeast coast of China, comprised of Hong Kong Island, Kowloon Peninsula, and New Territories. The three sites were ceded to the British by the Chinese respectively in 1841, 1860, and 1898. Hong Kong reverted to China in July 1997. The name represents the Cantonese pronunciation of the Chinese xianggang, fragrant port, from xiang, perfume and gang, port or harbor, with reference to its currents sweetened by fresh water from a river west of it.Influenza Pandemic, 1918-1919: The influenza outbreaks of 1918 to 1919 also known as Spanish flu pandemic. First reported in Haskell County in Kansas in March of 1918 the disease spread throughout the world and may have killed as many as 25 million people.Infant, Newborn: An infant during the first month after birth.Drug Resistance, Viral: The ability of viruses to resist or to become tolerant to chemotherapeutic agents or antiviral agents. This resistance is acquired through gene mutation.Poultry: Domesticated birds raised for food. It typically includes CHICKENS; TURKEYS, DUCKS; GEESE; and others.Swine Diseases: Diseases of domestic swine and of the wild boar of the genus Sus.SingaporeAge Distribution: The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Virology: The study of the structure, growth, function, genetics, and reproduction of viruses, and VIRUS DISEASES.MexicoInfluenza B virus: Species of the genus INFLUENZAVIRUS B that cause HUMAN INFLUENZA and other diseases primarily in humans. Antigenic variation is less extensive than in type A viruses (INFLUENZA A VIRUS) and consequently there is no basis for distinct subtypes or variants. Epidemics are less likely than with INFLUENZA A VIRUS and there have been no pandemics. Previously only found in humans, Influenza B virus has been isolated from seals which may constitute the animal reservoir from which humans are exposed.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Madin Darby Canine Kidney Cells: An epithelial cell line derived from a kidney of a normal adult female dog.United StatesSchools: Educational institutions.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Epidemics: Sudden outbreaks of a disease in a country or region not previously recognized in that area, or a rapid increase in the number of new cases of a previous existing endemic disease. Epidemics can also refer to outbreaks of disease in animal or plant populations.Hemagglutinins: Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc.Health Personnel: Men and women working in the provision of health services, whether as individual practitioners or employees of health institutions and programs, whether or not professionally trained, and whether or not subject to public regulation. (From A Discursive Dictionary of Health Care, 1976)Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Rimantadine: An RNA synthesis inhibitor that is used as an antiviral agent in the prophylaxis and treatment of influenza.Influenza A Virus, H7N9 Subtype: A subtype of INFLUENZA A VIRUS with the surface proteins hemagglutinin 7 and neuraminidase 9. This avian origin virus was first identified in humans in 2013.China: A country spanning from central Asia to the Pacific Ocean.World Health Organization: A specialized agency of the United Nations designed as a coordinating authority on international health work; its aim is to promote the attainment of the highest possible level of health by all peoples.Australia: The smallest continent and an independent country, comprising six states and two territories. Its capital is Canberra.Health Planning Guidelines: Recommendations for directing health planning functions and policies. These may be mandated by PL93-641 and issued by the Department of Health and Human Services for use by state and local planning agencies.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Vibrio cholerae: The etiologic agent of CHOLERA.Adjuvants, Immunologic: Substances that augment, stimulate, activate, potentiate, or modulate the immune response at either the cellular or humoral level. The classical agents (Freund's adjuvant, BCG, Corynebacterium parvum, et al.) contain bacterial antigens. Some are endogenous (e.g., histamine, interferon, transfer factor, tuftsin, interleukin-1). Their mode of action is either non-specific, resulting in increased immune responsiveness to a wide variety of antigens, or antigen-specific, i.e., affecting a restricted type of immune response to a narrow group of antigens. The therapeutic efficacy of many biological response modifiers is related to their antigen-specific immunoadjuvanticity.Thailand: Formerly known as Siam, this is a Southeast Asian nation at the center of the Indochina peninsula. Bangkok is the capital city.Infection Control: Programs of disease surveillance, generally within health care facilities, designed to investigate, prevent, and control the spread of infections and their causative microorganisms.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Asia: The largest of the continents. It was known to the Romans more specifically as what we know today as Asia Minor. The name comes from at least two possible sources: from the Assyrian asu (to rise) or from the Sanskrit usa (dawn), both with reference to its being the land of the rising sun, i.e., eastern as opposed to Europe, to the west. (From Webster's New Geographical Dictionary, 1988, p82 & Room, Brewer's Dictionary of Names, 1992, p34)Seroepidemiologic Studies: EPIDEMIOLOGIC STUDIES based on the detection through serological testing of characteristic change in the serum level of specific ANTIBODIES. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.Strategic Stockpile: Planned and coordinated pre-event accumulation of ESSENTIAL DRUGS and medical supplies.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Patient Isolation: The segregation of patients with communicable or other diseases for a specified time. Isolation may be strict, in which movement and social contacts are limited; modified, where an effort to control specified aspects of care is made in order to prevent cross infection; or reverse, where the patient is secluded in a controlled or germ-free environment in order to protect him or her from cross infection.Hemagglutinins, Viral: Specific hemagglutinin subtypes encoded by VIRUSES.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Amantadine: An antiviral that is used in the prophylactic or symptomatic treatment of influenza A. It is also used as an antiparkinsonian agent, to treat extrapyramidal reactions, and for postherpetic neuralgia. The mechanisms of its effects in movement disorders are not well understood but probably reflect an increase in synthesis and release of dopamine, with perhaps some inhibition of dopamine uptake.Mice, Inbred BALB C