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.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.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.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 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.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 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.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.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.Influenza 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.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.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.Orthomyxoviridae Infections: Virus diseases caused by the ORTHOMYXOVIRIDAE.Poultry: Domesticated birds raised for food. It typically includes CHICKENS; TURKEYS, DUCKS; GEESE; and others.Influenza A Virus, H7N7 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 7 and neuraminidase 7. The H7N7 subtype produced an epidemic in 2003 which was highly pathogenic among domestic birds (POULTRY). Some infections in humans were reported.Influenza A Virus, H5N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 5 and neuraminidase 2. The H5N2 subtype has been found to be highly pathogenic in chickens.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.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.DucksNeuraminidase: 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)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, 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.Anseriformes: An order of BIRDS comprising the waterfowl, particularly DUCKS; GEESE; swans; and screamers.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.Influenza A Virus, H3N8 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 3 and neuraminidase 8. The H3N8 subtype has frequently been found in horses.Oseltamivir: An acetamido cyclohexene that is a structural homolog of SIALIC ACID and inhibits NEURAMINIDASE.Hemagglutinins, Viral: Specific hemagglutinin subtypes encoded by VIRUSES.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.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.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).Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Cloaca: A dilated cavity extended caudally from the hindgut. In adult birds, reptiles, amphibians, and many fishes but few mammals, cloaca is a common chamber into which the digestive, urinary and reproductive tracts discharge their contents. In most mammals, cloaca gives rise to LARGE INTESTINE; URINARY BLADDER; and GENITALIA.Poultry Diseases: Diseases of birds which are raised as a source of meat or eggs for human consumption and are usually found in barnyards, hatcheries, etc. The concept is differentiated from BIRD DISEASES which is for diseases of birds not considered poultry and usually found in zoos, parks, and the wild.Receptors, Virus: Specific molecular components of the cell capable of recognizing and interacting with a virus, and which, after binding it, are capable of generating some signal that initiates the chain of events leading to the biological response.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, H7N3 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 7 and neuraminidase 3. It was first detected in turkeys in Britain in 1963 and there have been several outbreaks on poultry farms since that time. A couple cases of human infections have been reported.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)Influenza A Virus, H7N1 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 7 and neuraminidase 1. This subtype has demonstrated the ability to mutate from a low pathogenic form to a highly pathogenic form in birds. It was responsible for a 1999 outbreak in turkeys in Italy.Viral Proteins: Proteins found in any species of virus.Zoonoses: Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.Virus Diseases: A general term for diseases produced by viruses.Viruses: Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells.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.RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.RNA Viruses: Viruses whose genetic material is RNA.Vaccination: Administration of vaccines to stimulate the host's immune response. This includes any preparation intended for active immunological prophylaxis.Animals, Wild: Animals considered to be wild or feral or not adapted for domestic use. It does not include wild animals in zoos for which ANIMALS, ZOO is available.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.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.Antigens, Viral: Substances elaborated by viruses that have antigenic activity.GeeseInfluenza A Virus, H7N2 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 7 and neuraminidase 2. It has been involved in a number of outbreaks in the 21st century on poultry farms and has been isolated a few times in humans.Communicable Diseases, Emerging: Infectious diseases that are novel in their outbreak ranges (geographic and host) or transmission mode.Virus Cultivation: Process of growing viruses in live animals, plants, or cultured cells.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Madin Darby Canine Kidney Cells: An epithelial cell line derived from a kidney of a normal adult female dog.Zanamivir: A guanido-neuraminic acid that is used to inhibit NEURAMINIDASE.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.Genes, Viral: The functional hereditary units of VIRUSES.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)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.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.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.Vaccinia virus: The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.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)Bird Diseases: Diseases of birds not considered poultry, therefore usually found in zoos, parks, and the wild. The concept is differentiated from POULTRY DISEASES which is for birds raised as a source of meat or eggs for human consumption, and usually found in barnyards, hatcheries, etc.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.Charadriiformes: An order of BIRDS including over 300 species that primarily inhabit coastal waters, beaches, and marshes. They are comprised of shorebirds, gulls, and terns.Pneumonia, Viral: Inflammation of the lung parenchyma that is caused by a viral infection.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.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).Animal Migration: Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.RNA Replicase: An enzyme that catalyses RNA-template-directed extension of the 3'- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. (Enzyme Nomenclature, 1992, p293)Enterovirus: A genus of the family PICORNAVIRIDAE whose members preferentially inhabit the intestinal tract of a variety of hosts. The genus contains many species. Newly described members of human enteroviruses are assigned continuous numbers with the species designated "human enterovirus".Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.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.Vaccines, Attenuated: Live vaccines prepared from microorganisms which have undergone physical adaptation (e.g., by radiation or temperature conditioning) or serial passage in laboratory animal hosts or infected tissue/cell cultures, in order to produce avirulent mutant strains capable of inducing protective immunity.Virology: The study of the structure, growth, function, genetics, and reproduction of viruses, and VIRUS DISEASES.Viral Matrix Proteins: Proteins associated with the inner surface of the lipid bilayer of the viral envelope. These proteins have been implicated in control of viral transcription and may possibly serve as the "glue" that binds the nucleocapsid to the appropriate membrane site during viral budding from the host cell.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.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)Influenzavirus A: A genus in the family ORTHOMYXOVIRIDAE causing influenza and other diseases in humans and animals. It contains many strains as well as antigenic subtypes of the integral membrane proteins hemagglutinin (HEMAGGLUTININS) and NEURAMINIDASE. The type species is INFLUENZA A VIRUS.Oncogenic Viruses: Viruses that produce tumors.Neutralization Tests: The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).Chick Embryo: The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.Shellfish: Aquatic invertebrates belonging to the phylum MOLLUSCA or the subphylum CRUSTACEA, and used as food.Nucleoproteins: Proteins conjugated with nucleic acids.China: A country spanning from central Asia to the Pacific Ocean.Disaster Planning: Procedures outlined for the care of casualties and the maintenance of services in disasters.Virus Inactivation: Inactivation of viruses by non-immune related techniques. They include extremes of pH, HEAT treatment, ultraviolet radiation, IONIZING RADIATION; DESICCATION; ANTISEPTICS; DISINFECTANTS; organic solvents, and DETERGENTS.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.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.Mice, Inbred BALB CInfluenzavirus C: A genus of the family ORTHOMYXOVIRIDAE comprising viruses similar to types A and B but less common, more stable, more homogeneous, and lacking the neuraminidase protein. They have not been associated with epidemics but may cause mild influenza. Influenza C virus is the type species.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Virus Assembly: The assembly of VIRAL STRUCTURAL PROTEINS and nucleic acid (VIRAL DNA or VIRAL RNA) to form a VIRUS PARTICLE.Rimantadine: An RNA synthesis inhibitor that is used as an antiviral agent in the prophylaxis and treatment of influenza.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Swine Diseases: Diseases of domestic swine and of the wild boar of the genus Sus.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Respiratory System: The tubular and cavernous organs and structures, by means of which pulmonary ventilation and gas exchange between ambient air and the blood are brought about.Antibodies, Neutralizing: Antibodies that reduce or abolish some biological activity of a soluble antigen or infectious agent, usually a virus.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).VietnamDefective Viruses: Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.Viral Core Proteins: Proteins found mainly in icosahedral DNA and RNA viruses. They consist of proteins directly associated with the nucleic acid inside the NUCLEOCAPSID.Simian virus 40: A species of POLYOMAVIRUS originally isolated from Rhesus monkey kidney tissue. It produces malignancy in human and newborn hamster kidney cell cultures.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.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.Polysorbates: Sorbitan mono-9-octadecanoate poly(oxy-1,2-ethanediyl) derivatives; complex mixtures of polyoxyethylene ethers used as emulsifiers or dispersing agents in pharmaceuticals.Virus Attachment: The binding of virus particles to receptors on the host cell surface. For enveloped viruses, the virion ligand is usually a surface glycoprotein as is the cellular receptor. For non-enveloped viruses, the virus CAPSID serves as the ligand.Viral Plaque Assay: Method for measuring viral infectivity and multiplication in CULTURED CELLS. Clear lysed areas or plaques develop as the VIRAL PARTICLES are released from the infected cells during incubation. With some VIRUSES, the cells are killed by a cytopathic effect; with others, the infected cells are not killed but can be detected by their hemadsorptive ability. Sometimes the plaque cells contain VIRAL ANTIGENS which can be measured by IMMUNOFLUORESCENCE.Time Factors: Elements of limited time intervals, contributing to particular results or situations.PyransReverse Genetics: The use of techniques that produce a functional MUTATION or an effect on GENE EXPRESSION of a specific gene of interest in order to identify the role or activity of the gene product of that gene.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.DelawareDNA Viruses: Viruses whose nucleic acid is DNA.Water Pollution: Contamination of bodies of water (such as LAKES; RIVERS; SEAS; and GROUNDWATER.)History, 20th Century: Time period from 1901 through 2000 of the common era.Hemagglutination, Viral: Agglutination of ERYTHROCYTES by a virus.Plant Viruses: Viruses parasitic on plants higher than bacteria.Turkeys: Large woodland game BIRDS in the subfamily Meleagridinae, family Phasianidae, order GALLIFORMES. Formerly they were considered a distinct family, Melegrididae.Thailand: Formerly known as Siam, this is a Southeast Asian nation at the center of the Indochina peninsula. Bangkok is the capital city.Cardiovirus: A genus of the family PICORNAVIRIDAE causing encephalitis and myocarditis in rodents. ENCEPHALOMYOCARDITIS VIRUS is the type species.Viral Nonstructural Proteins: Proteins encoded by a VIRAL GENOME that are produced in the organisms they infect, but not packaged into the VIRUS PARTICLES. Some of these proteins may play roles within the infected cell during VIRUS REPLICATION or act in regulation of virus replication or VIRUS ASSEMBLY.Respiratory Syncytial Viruses: A group of viruses in the PNEUMOVIRUS genus causing respiratory infections in various mammals. Humans and cattle are most affected but infections in goats and sheep have also been reported.Sindbis Virus: The type species of ALPHAVIRUS normally transmitted to birds by CULEX mosquitoes in Egypt, South Africa, India, Malaya, the Philippines, and Australia. It may be associated with fever in humans. Serotypes (differing by less than 17% in nucleotide sequence) include Babanki, Kyzylagach, and Ockelbo viruses.Measles virus: The type species of MORBILLIVIRUS and the cause of the highly infectious human disease MEASLES, which affects mostly children.Host Specificity: The properties of a pathogen that makes it capable of infecting one or more specific hosts. The pathogen can include PARASITES as well as VIRUSES; BACTERIA; FUNGI; or PLANTS.Mass Vaccination: Administration of a vaccine to large populations in order to elicit IMMUNITY.SqualeneAdministration, Intranasal: Delivery of medications through the nasal mucosa.Virion: The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.Parvovirus: A genus of the family PARVOVIRIDAE, subfamily PARVOVIRINAE, infecting a variety of vertebrates including humans. Parvoviruses are responsible for a number of important diseases but also can be non-pathogenic in certain hosts. The type species is MINUTE VIRUS OF MICE.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Vero Cells: A CELL LINE derived from the kidney of the African green (vervet) monkey, (CERCOPITHECUS AETHIOPS) used primarily in virus replication studies and plaque assays.United StatesWorld Health: The concept pertaining to the health status of inhabitants of the world.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)Sialic Acids: A group of naturally occurring N-and O-acyl derivatives of the deoxyamino sugar neuraminic acid. They are ubiquitously distributed in many tissues.Rabies virus: The type species of LYSSAVIRUS causing rabies in humans and other animals. Transmission is mostly by animal bites through saliva. The virus is neurotropic multiplying in neurons and myotubes of vertebrates.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.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Respiratory Tract Infections: Invasion of the host RESPIRATORY SYSTEM by microorganisms, usually leading to pathological processes or diseases.Hospitalization: The confinement of a patient in a hospital.Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Public Health Surveillance: The ongoing, systematic collection, analysis, and interpretation of health-related data with the purpose of preventing or controlling disease or injury, or of identifying unusual events of public health importance, followed by the dissemination and use of information for public health action. (From Am J Prev Med 2011;41(6):636)Nasopharynx: The top portion of the pharynx situated posterior to the nose and superior to the SOFT PALATE. The nasopharynx is the posterior extension of the nasal cavities and has a respiratory function.Recombination, Genetic: Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.North AmericaViral Load: The quantity of measurable virus in a body fluid. Change in viral load, measured in plasma, is sometimes used as a SURROGATE MARKER in disease progression.Egypt: A country in northern Africa, bordering the Mediterranean Sea, between Libya and the Gaza Strip, and the Red Sea north of Sudan, and includes the Asian Sinai Peninsula Its capital is Cairo.Haplorhini: A suborder of PRIMATES consisting of six families: CEBIDAE (some New World monkeys), ATELIDAE (some New World monkeys), CERCOPITHECIDAE (Old World monkeys), HYLOBATIDAE (gibbons and siamangs), CALLITRICHINAE (marmosets and tamarins), and HOMINIDAE (humans and great apes).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.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Indonesia: A republic stretching from the Indian Ocean east to New Guinea, comprising six main islands: Java, Sumatra, Bali, Kalimantan (the Indonesian portion of the island of Borneo), Sulawesi (formerly known as the Celebes) and Irian Jaya (the western part of New Guinea). Its capital is Djakarta. The ethnic groups living there are largely Chinese, Arab, Eurasian, Indian, and Pakistani; 85% of the peoples are of the Islamic faith.Disease Reservoirs: Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (DISEASE VECTORS) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks.Vesicular stomatitis Indiana virus: The type species of VESICULOVIRUS causing a disease symptomatically similar to FOOT-AND-MOUTH DISEASE in cattle, horses, and pigs. It may be transmitted to other species including humans, where it causes influenza-like symptoms.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.Enzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.N-Acetylneuraminic Acid: An N-acyl derivative of neuraminic acid. N-acetylneuraminic acid occurs in many polysaccharides, glycoproteins, and glycolipids in animals and bacteria. (From Dorland, 28th ed, p1518)Hemagglutination Tests: Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)Specific Pathogen-Free Organisms: Animals or humans raised in the absence of a particular disease-causing virus or other microorganism. Less frequently plants are cultivated pathogen-free.Hepatitis B virus: The type species of the genus ORTHOHEPADNAVIRUS which causes human HEPATITIS B and is also apparently a causal agent in human HEPATOCELLULAR CARCINOMA. The Dane particle is an intact hepatitis virion, named after its discoverer. Non-infectious spherical and tubular particles are also seen in the serum.West Nile virus: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE). It can infect birds and mammals. In humans, it is seen most frequently in Africa, Asia, and Europe presenting as a silent infection or undifferentiated fever (WEST NILE FEVER). The virus appeared in North America for the first time in 1999. It is transmitted mainly by CULEX spp mosquitoes which feed primarily on birds, but it can also be carried by the Asian Tiger mosquito, AEDES albopictus, which feeds mainly on mammals.Serial Passage: Inoculation of a series of animals or in vitro tissue with an infectious bacterium or virus, as in VIRULENCE studies and the development of vaccines.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Epidemiological Monitoring: Collection, analysis, and interpretation of data about the frequency, distribution, and consequences of disease or health conditions, for use in the planning, implementing, and evaluating public health programs.Genetic Variation: Genotypic differences observed among individuals in a population.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Gene Expression Regulation, Viral: Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.Sequence Homology: The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.Antigenic Variation: Change in the surface ANTIGEN of a microorganism. There are two different types. One is a phenomenon, especially associated with INFLUENZA VIRUSES, where they undergo spontaneous variation both as slow antigenic drift and sudden emergence of new strains (antigenic shift). The second type is when certain PARASITES, especially trypanosomes, PLASMODIUM, and BORRELIA, survive the immune response of the host by changing the surface coat (antigen switching). (From Herbert et al., The Dictionary of Immunology, 4th ed)Virus Activation: The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.Parainfluenza Virus 1, Human: A species of RESPIROVIRUS also called hemadsorption virus 2 (HA2), which causes laryngotracheitis in humans, especially children.Adenoviruses, Human: Species of the genus MASTADENOVIRUS, causing a wide range of diseases in humans. Infections are mostly asymptomatic, but can be associated with diseases of the respiratory, ocular, and gastrointestinal systems. Serotypes (named with Arabic numbers) have been grouped into species designated Human adenovirus A-F.Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.Viral Tropism: The specificity of a virus for infecting a particular type of cell or tissue.Vaccines, Synthetic: Small synthetic peptides that mimic surface antigens of pathogens and are immunogenic, or vaccines manufactured with the aid of recombinant DNA techniques. The latter vaccines may also be whole viruses whose nucleic acids have been modified.Infant, Newborn: An infant during the first month after birth.Cytopathogenic Effect, Viral: Visible morphologic changes in cells infected with viruses. It includes shutdown of cellular RNA and protein synthesis, cell fusion, release of lysosomal enzymes, changes in cell membrane permeability, diffuse changes in intracellular structures, presence of viral inclusion bodies, and chromosomal aberrations. It excludes malignant transformation, which is CELL TRANSFORMATION, VIRAL. Viral cytopathogenic effects provide a valuable method for identifying and classifying the infecting viruses.Military Facilities: Areas designated for use by the armed forces personnel.Immunization Programs: Organized services to administer immunization procedures in the prevention of various diseases. The programs are made available over a wide range of sites: schools, hospitals, public health agencies, voluntary health agencies, etc. They are administered to an equally wide range of population groups or on various administrative levels: community, municipal, state, national, international.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Immunization: Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).Myxovirus Resistance Proteins: Interferon-induced DYNAMIN-like GTP-binding proteins localized in the cytoplasm, nuclear pore complex and nucleus. They play a role in antiviral defense and immunity.Epitopes: Sites on an antigen that interact with specific antibodies.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.Newcastle Disease: An acute febrile, contagious, viral disease of birds caused by an AVULAVIRUS called NEWCASTLE DISEASE VIRUS. It is characterized by respiratory and nervous symptoms in fowl and is transmissible to man causing a severe, but transient conjunctivitis.Pharynx: A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx).Respiratory Syncytial Virus Infections: Pneumovirus infections caused by the RESPIRATORY SYNCYTIAL VIRUSES. Humans and cattle are most affected but infections in goats and sheep have been reported.MexicoReal-Time Polymerase Chain Reaction: Methods used for detecting the amplified DNA products from the polymerase chain reaction as they accumulate instead of at the end of the reaction.
  • Influenza viruses circulating in the animal world do pose a threat to human health since they have mutated into a form that allows this. (hubpages.com)
  • According to the current analysis, performed at the Columbia University's Center for Computational Biology and Bioinformatics, it is from this pool of viruses that the current swine flu threat derives three-quarters of its genetic material. (motherearthnews.com)
  • Our findings elucidate the specific mutations in PB2 contribute to the phenotype differences and emphasize the importance of monitoring the identified amino acid substitutions due to their potential threat to human health. (nature.com)
  • Jean St phenne, President of GSK Biologicals, the vaccine division of GSK, said: Receiving this positive opinion today from the CHMP is testament to the company s ongoing commitment to provide health authorities with concrete options against the threat of an influenza pandemic. (webwire.com)
  • AI viruses have contributed significantly to this, and in recent years, highly pathogenic AI (HPAI) viruses have emerged as a major zoonotic threat. (frontiersin.org)
  • A look at the history of pandemic flu can help us understand why the H5N1 virus remains a serious threat to mankind. (realitysandwich.com)
  • Recommended activities are specific to the threat posed by the continuing spread of the H5N1 virus. (who.int)
  • In view of the immediacy of the threat, WHO recommends that all countries undertake urgent action to prepare for a pandemic. (who.int)
  • Given the many uncertainties about the evolution of the pandemic threat, including the amount of time left to prepare, a wise approach involves a mix of measures that immediately address critical problems with longer-term measures that sustainably improve the world's capacity to protect itself against the recurring pandemic threat. (who.int)
  • The clearance of this test represents a major step toward protecting the public from the threat of pandemic flu. (netdoc.com)
  • Until now it is unclear whether these bat-derived viruses are circulating in any non-bat species and whether they pose a zoonotic threat. (emeter.com)
  • This strain is common, has mild symptoms, and doesn't pose a significant threat to human health. (alpharubicon.com)
  • The flu virus is a moving target, antigenically speaking, and so vaccine manufacture lags viral innovation. (rkm.com.au)
  • Clinical features and rapid viral diagnosis of human disease associated with avian influenza A H5N1 virus. (nih.gov)
  • The fluorescence signal for glycan #18 in the Utah virus pair includes nonspecific binding by the primary sheep antibody and cannot be interpreted as viral (data not shown). (nih.gov)
  • Samji, T. (2009) Influenza A: Understanding the viral life cycle. (scirp.org)
  • Furthermore, examination of infected tissues revealed cellular damage at sites containing viral proteins, providing an explanation for the increased severity of disease in humans. (bio-medicine.org)
  • The species barriers that hinder most avian IAVs from successfully infecting humans are effective at several steps in the viral life cycle. (nature.com)
  • Despite these differences in receptor binding, many avian viruses are internalized by human cells and initiate expression of the viral genome. (nature.com)
  • One well-established factor is the influenza RNA-dependent RNA polymerase (RdRP): this enzyme catalyzes replication of the viral genome and transcription of viral messenger RNAs (mRNAs) 3 . (nature.com)
  • However, they add, "Changes in other viral proteins, including PB2, may be required to confer pandemic potential on avian viruses that can efficiently replicate in humans. (umn.edu)
  • The criterion standard for diagnosing influenza A and B is a viral culture of nasopharyngeal samples or throat samples. (medscape.com)
  • Of course, viruses don't actually have sex, but University of Maryland Virologist Daniel Perez, who directed the new study, said new pandemic viruses are formed mainly through a process called reassortment, which can best be described as viral sexual reproduction. (medindia.net)
  • The neuraminidase inhibitor zanamivir inhibited viral replication in Madin-Darby canine kidney cells in virus yield assays (50% effective concentration, 8.5 to 14.0 μM) and inhibited viral neuraminidase activity (50% inhibitory concentration, 5 to 10 nM). (pubmedcentralcanada.ca)
  • The focus of the Foung Laboratory is to define immune correlates of protection against hepatitis C virus and other viral pathogens. (stanford.edu)
  • More specifically, our goal is to define protective humoral immunity to viral pathogens through the isolation, biochemical and functional characterization of broadly neutralizing human or nonhuman primate monoclonal antibodies. (stanford.edu)
  • The influenza virus that wreaked worldwide havoc in 1918-1919 founded a viral dynasty that persists to this day, according to scientists from the National Institute of Allergy and Infectious Diseases (NIAID). (infectioncontroltoday.com)
  • Clinical and pathological features in H5N1- and 1918-infected humans and animal models ( 6 - 12 ) suggest that high levels of viral replication with early robust host responses play a key role in pneumonia severity and outcome. (pnas.org)
  • The GPAI is designed to provide emergency financing to participating countries to contain outbreaks of avian flu through early detection and rapid response measures. (worldbank.org)
  • The spread of avian influenza A viruses from one ill person to another has been reported very rarely, and when it has been reported it has been limited, inefficient and not sustained. (emeter.com)
  • This seems to be the recipe for the next influenza pandemic. (rkm.com.au)
  • This document sets out activities that can be undertaken by individual countries, the international community, and WHO to prepare the world for the next influenza pandemic and mitigate its impact once international spread has begun. (who.int)
  • and improved equity in supply of pharmaceutical products, as well as availability of basic health services, during a global influenza crisis. (cdc.gov)
  • We are forced to deal with surrogate data because, thank goodness, there are little data on the release of potentially pandemic agents. (thebulletin.org)
  • Put another way, surrogate data allows us to determine with confidence the probability of release of a potentially pandemic pathogen into the community. (thebulletin.org)
  • Second, companies need to engage in research on pandemic vaccine development that includes pilot production of small batches for clinical testing. (news-medical.net)