any power, principle, or substance capable of producing an effect, whether chemical, physical, or biological.AIDS
acquired immunodeficiency syndrome, the end stage of HIV disease.Airborne
the dissemination of microbial agents through a suitable portal of entry, usually the respiratory tract. Microbial aerosols are suspensions of particles in the air consisting partially or wholly of microorganisms.Allograft
a homograft between allogeneic individuals.Anthropophilic
attracted to humans especially as a source of food (anthropophilic mosquitoes); indicating relative attraction to humans.Antibiotic
chemical substance produced by a microorganism that has the capacity to inhibit the growth of or to kill other microorganisms; antibiotics that are nontoxic to the host are used as chemotherapeutic agents in the treatment of infectious diseases.Antibody
a protein produced by the immune system in response to the introduction of a substance (an antigen) recognized as foreign by the body’s immune system. Antibody interacts with the other components of the immune system and can render the antigen harmless, although for various reasons this may not always occur.Antigen
a molecule capable of eliciting a specific antibody or T-cell response; a molecule specifically reacting with an antibody.Antigenic
having the properties of an antigen.
a chemotherapeutic agent that inhibits or destroys malarial parasites.Antimicrobial
a drug for killing microorganisms or suppressing their multiplication or growth. For the purposes of this report, antimicrobials include antibiotics and antivirals.Antiretroviral
substance that stops or suppresses the activity of a retrovirus such as HIV.Antiviral
drugs, including interferon, that stimulate cellular defenses against viruses, reducing cell DNA synthesis and making cells more resistant to viral genes, enhancing cellular immune responses or suppressing their replication.Arbovirus
shortened form of arthropod-borne virus. Any of a group of viruses that are transmitted to humans and animals by mosquitoes, ticks, and sand flies; they include such agents as yellow fever and eastern, western, and Venezuelan equine encephalitis virus.Arenavirus
any group of viruses composed of pleomorphic virions of varying size, one large and one small segment of single-stranded RNA, and ribosomes within the virions that cause the virus to have a sandy appearance. Examples are Junin, Machupo, and Lassa fever viruses. Rodents are common reservoirs of the arenaviruses.Arthropod
as used in this report, refers to insects and ticks, many of which are medically important as vectors of infectious diseases.Arthropod-borne
capable of being transmitted by insect and tick (arthropod) vectors.
one of two general categories of lymphocytes (white blood cells) involved in the humoral immune response. When help is provided by T lymphocytes, B lymphocytes produce antibodies against specific antigens.Bacillus
refers to the presence of bacteria in the blood.Bacteria
one of the two major classes of prokaryotic organism.Beta-lactam
an active portion of an antibiotic (e.g., penicillin or cephalosporin) that is part of the chemical structure of the antibiotic and that can be neutralized by a beta-lactamase produced by certain microorganisms (e.g., some staphylococci).Beta-lactamase
an enzyme that neutralizes the effect of an antibiotic containing beta-lactam.Bioterrorism
terrorism using biological agents. Biological diseases and the agents that might be used for terrorism have been labeled by the CDC and comprise viruses, bacteria, rickettsiae, fungi, and biological toxins. These agents have been classified according to the degree of danger each agent is felt to pose into one of three categories.
level of containment required for safe handling of the most contagious pathogenic microbes.
usually expressed as the percentage of persons diagnosed as having a specified disease who die as a result of that illness within a given period.Category A
high-priority agents include organisms that pose a risk to national security because they can be easily disseminated or transmitted person-to-person, cause high mortality, with potential for major public health impact, might cause public panic and social disruption, and require special action for public health preparedness. These diseases include anthrax, botulism, plague, smallpox, tularemia, and viral hemorrhagic fevers.Category B
second-highest priority agents include those that are moderately easy to disseminate, cause moderate morbidity and low mortality, and require specific diagnostic capacity and enhanced disease surveillance. These agents/diseases include Q fever brucellosis, glanders, ricin toxin, epsilon toxin, and staph toxin.Category C
third-highest priority agents include emerging pathogens that could be engineered for mass dissemination in the future because of availability, ease of production and dissemination, and potential for high mortality and major health impact. These agents/diseases include Nipah virus, hantavirus, tickborne hemorrhagic fever viruses, tickborne encephalitis viruses, yellow fever, and tuberculosis.Cellular immunity, cell-mediated immunity
a type of immune response in which subpopulations of T cells (helper T cells and killer T cells) cooperate to destroy cells in the body that bear foreign antigens, such as bacteria.Cephalosporin
a class of antibiotic.Chemokine
any of a group of chemotactic cytokines that are produced by various cells (as at sites of inflammation), that are thought to provide directional cues for the movement of white blood cells (as T cells, monocytes, and neutrophils), and that include some playing a role in HIV infection because the cell surface receptors to which they bind are also used by specific strains of HIV for entry into cells.Chronic disease
diseases that have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care.Clonal
of or pertaining to a group of genetically identical organisms derived from a single parent or a DNA population derived from a single DNA molecule by replication in a bacterial or eukaryotic host cell.
the order of nucleotide bases in a nucleic acid that specifies the production of a particular product, such as a protein. A change in the coding sequence (e.g., as a result of mutation) can result in a change in the product.Communicable disease
an illness due to a specific infectious agent or its toxic products that arises though transmission of that agent or its products from an infected person, animal, or inanimate reservoir to a susceptible host; either directly or indirectly through an intermediate plant or animal host, vector, or inanimate environment; infectious disease.Contagious
communicable by contact; bearing contagion.Cytokine
any of a class of immunoregulatory proteins (as interleukin, tumor necrosis factor, and interferon) that are secreted by cells, especially of the immune system.
1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane or chlorophenothane, a pesticide.Deletion mutation
a mutation that results from the deletion of one or more amino acids present in the genetic material of the organism undergoing the mutation.Disease
as used in this report, refers to a situation in which infection has elicited signs and symptoms in the infected individual; the infection has become clinically apparent.DNA
deoxyribonucleic acid, a carrier of genetic information (i.e., hereditary characteristics) found chiefly in the nucleus of cells.DNA virus
a virus that contains only DNA as its genetic material.Droplet nuclei
the very small particles of moisture expelled when a person coughs, sneezes, or speaks that may transfer infectious organisms to another person who inhales the droplets.
a branch of science concerned with the interrelationship of organisms and their environments.Ecosystem
the complex of a community and its environment functioning as an ecological unit in nature.Emerging infection
either a newly recognized, clinically distinct infectious disease, or a known infectious disease whose reported incidence is increasing in a given place or among a specific population.Encephalitis
inflammation of the brain.Endemic
the constant presence of a disease or infectious agent within a given geographic area; it may also refer to the usual prevalence of a given disease within such area.Endogenous
developing or originating from within the individual.Endophilic
ecologically associated with humans and their domestic environment (mosquitoes that are endophilic vectors of malaria).Entomology
a branch of zoology that deals with insects.
refers to a disease (can be either low or high morbidity) that is endemic in an animal community.Epidemic
the occurrence in a community or region of cases of an illness (or outbreak) with a frequency clearly in excess of normal expectancy.Epidemiology
branch of science that deals with the incidence, distribution, and control of disease in a population; the sum of the factors controlling the presence or abundance of a disease or pathogen.Epizootic
a disease of generally high morbidity that rapidly spreads through an animal population.Etiological agent
the organism that causes a disease.Etiology
the cause or origin of a disease.
a class of antibiotic.Foodborne illness
a sickness caused by food contaminated with microorganisms, chemicals, or other substances hazardous to human health.
the ability of a microorganism to adapt to its environment, often allowing it to avoid detection or an immune response generated against it.Genome
the complete genetic composition of an organism (e.g., human, bacterium, protozoan, helminth, or fungus), contained in a chromosome or set of chromosomes or in a DNA or RNA molecule (e.g., virus).Genomics
a branch of biotechnology concerned with applying the techniques of genetics and molecular biology to the genetic mapping and DNA sequencing of sets of genes or the complete genomes of selected organisms using high-speed methods, organizing the results in databases, and with applications of the data (as in medicine or biology).Glycoprotein
a conjugated protein in which the nonprotein group is a carbohydrate.Gram-negative
refers to the inability of a microorganism to accept a certain stain. This inability is related to the cell wall composition of the microorganism and has been useful in classifying bacteria.Gram-positive
refers to the ability of a microorganism to retain a certain stain. This ability is related to the cell wall composition of the microorganism and has been useful in classifying bacteria.
a group of alleles of different genes (as of the major histocompatibility complex) on a single chromosome that are closely enough linked to be inherited usually as a unit.Hemagglutinin
a molecule, such as an antibody or lectin, that agglutinates red blood cells.Hemoglobin
iron-containing respiratory pigment of vertebrate red blood cells that functions primarily in the transport of oxygen from the lungs to the tissues of the body.
a blood disorder (such as sickle cell anemia) caused by a genetically determined change in the molecular structure of hemoglobin.Hemorrhagic fever
a group of diverse, severe epidemic viral infections of worldwide distribution but occurring especially in tropical countries, that are usually transmitted to humans by arthropod bites or contact with virus-infected rodents or monkeys and that share common clinocopathological features (e.g., fever, hemorrhaging, shock, thrombocytopenia, neurological disturbances). Examples are Argentine, Bolivian, and Venezuelan hemorrhagic fevers; chikungunya; Rift Valley fever; and Ebola and Marburg virus diseases.Heterozygous
having the two genes at corresponding loci on homologous chromosomes different for one or more loci.HIV disease
the broad spectrum of opportunistic infections and diseases that occur in an individual infected with the human immunodeficiency virus.Homozygous
having the two genes at corresponding loci on homologous chromosomes identical for one or more loci.Host
a person or other living creature, including birds and arthropods, that affords subsistence or lodgment to an infectious agent under natural (as opposed to experimental) conditions.Humoral immunity
antibody-mediated immunity; one of the mechanisms, using antibodies found in the blood and other body fluids, that the body uses to fight off infections.Hyperendemic
the condition in which a disease is present in a community at all times and with a high incidence.
any consequence of treatment by a physician.Immunity
that resistance usually associated with the presence of antibodies or cells having a specific action on the microorganism concerned with a particular infectious disease or on its toxin.Immunization
a process that increases an organism’s reaction to antigen and therefore improves its ability to resist or overcome infection.Immunocompromised
a condition (caused, for example, by the administration of immunosuppressive drugs or irradiation, malnutrition, aging, or a condition such as cancer or HIV disease) in which an individual’s immune system is unable to respond adequately to a foreign substance.Immunosuppression
the retardation or cessation of an immune response as a result of, for example, anticancer drugs.Incidence rate
the number of new cases of a specified disease during a defined period of time divided by the number of persons in a stated population in which the cases occurred.
the entry and development (of many parasites) or a multiplication of an infectious agent in the body of persons or animals.Infectious
capable of causing infection; communicable by invasion of the body of a susceptible organism.Infectious agent
an organism (virus, rickettsia, bacteria, fungus, protozoan, or helminth) that is capable of producing infection or infectious disease.
any microorganism or biologic agent that can replicate in humans (including bacteria, viruses, protozoa, fungi, and prions); in other usage, any multicellular organism.Microbial traffic
the transfer of existing microbes to new host populations.Microbiome
the ensemble of microbes that may share the body space of a multicellular host, in health or disease; may be intra- or extracellular.Monoclonal antibody
immunoglobulins derived from a single clone of plasma cells. Monoclonal antibodies constitute a pure population because they are produced by a single clone in vitro and are chemically and structurally identical.Mutation
a transmissible change in the genetic material of an organism, usually in a single gene.
sialidase; an enzyme that catalyzes the hydrolysis of glucosidic linkages between a sialic acid residue and a hexose or hexosamine residue in glycoproteins, glycolipids, and proteoglycans. Neuraminidase is a major antigen of myxoviruses.Nosocomial infection
an infection occurring in a patient in a hospital or other health care facility in whom it was not present or incubating at the time of admission; or the residual infection acquired during a previous admission.
an infection caused by an organism that ordinarily does not cause disease but under circumstances such as impaired immunity becomes pathogenic.
an epidemic that occurs worldwide.Parasite
organism living in, with, or on another organism.Pathogen
a microorganism that causes disease.Pathogenic
capable of causing disease.PCR
see polymerase chain reaction.Pharmacokinetics
the study of bodily absorption, distribution, metabolism, and excretion of drugs; the characteristic interactions of a drug and the body in terms of its absorption, distribution, metabolism, and excretion.Plasmid
an extrachromosomal, self-replicating structure found in cells that carries genes for a variety of functions not essential for cell growth. Plasmids are any extranuclear genetic particle.
a mutation resulting from a change in a single base pair in the DNA molecule, resulting from the substitution of one nucleotide for another.Polymerase chain reaction
a laboratory method of amplifying low levels of specific microbial DNA or RNA sequences.Prevalence rate
the total number of persons sick or portraying a certain condition in a stated population at a particular time or during a stated period of time, regardless of when that illness or condition began, divided by the population at risk of having the disease or condition at the point in time midway through the period in which they occurred.Probiotic
general term for a substance that promotes growth of microorganisms; an organism that changes health of carrier.Public health
the art and science of dealing with the protection and improvement of community health by organized community effort and including preventive medicine and sanitary and social health.
a cell or group of cells that receive(s) stimuli; a chemical group or molecule (such as a protein) on the cell surface or in the cell interior that has an affinity for a specific chemical group, molecule, or virus.Recombination
the formation of new combinations of genes as a result of crossing over (exchange of genes) between structurally similar chromosomes, resulting in progeny with different gene combinations than in the parents.Reservoir
any person, animal, arthropod, plant, soil, or substance (or combination of these) in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host.Resistance
the sum total of body mechanisms that interpose barriers to the invasion or multiplication of infectious agents, or to damage by their toxic products.Retrovirus
any of large family of RNA viruses that includes lentiviruses and oncoviruses, so called because they carry reverse transcriptase.Reverse transcriptase
RNA-directed DNA polymerase; an enzyme, such as is found in the human immunodeficiency virus, that catalyzes the reaction that uses RNA as a template for double-stranded DNA synthesis.RNA
ribonucleic acid.RNA virus
a virus that contains RNA as its genetic material.Rodent-borne
disease spread by rodents.
pressure exerted on an organism by its environment that causes a change in the organism’s ability to cope with that environment.
systemic disease associated with the presence and persistence of microorganisms in the blood.Seroconversion
the change of a serological test result from negative to positive as a result of antibodies induced by the introduction of micro-organisms into the host.Serological
the use of immune serum in any number of tests (agglutination, precipitation, enzyme-linked immunosorbent assay, etc.) used to measure the response (antibody titer) to infectious disease; the use of serological reactions to detect antigen.Seronegative
negative result in a serological test; that is, the inability to detect the antibodies or antigens being tested for.Seropositive
positive results in a serological test.Serotype
the characterization of a microorganism based on the kinds and combinations of constituent antigens present in that organism; a taxonomic subdivision of bacteria based on the above.Slow virus
any virus (or virus-like agent) causing a disease characterized by a very long preclinical course and a very gradual progression of symptoms; many examples are prions.Strain
a subgrouping of organisms within a species, characterized by some particular quality.Surveillance
the continuing scrutiny of all aspects of occurrence and spread of a disease that are pertinent to effective control.Syndrome
a set of symptoms that may occur concurrently.
any of several lymphocytes (such as a helper T cell) that differentiate in the thymus, process highly specific cell-surface antigen receptors, and include some that control the initiation or suppression of cell-mediated and humoral immunity and others that lyse antigen-bearing cells.Tetramer
molecule (such as an enzyme or polymer) that consists of four structural subunits.Toll
the Toll signaling pathway, which is required for the establishment of the dorsal ventral axis in Drosophila embryos, plays an important role in the response of larval and adult Drosophila to microbial infections.Toll-like receptor
a system of innate immunity originally discovered in Drosophila.Transovarially
relating to or being transmission of a pathogen from an organism (such as a tick) to its offspring by infection of eggs in its ovary.
a preparation of purified polypeptide, protein or polysaccharide, or DNA or of killed microorganisms, living attenuated organisms, or living virulent or crude or purified organisms that is administered to produce or artificially increase immunity to a particular disease.
a carrier, especially an arthropod, that transfers an infective agent from one host (which can include itself) to another.Vector-borne
(i) Mechanical: includes simple mechanical carriage by a crawling or flying insect through soiling of its feet or proboscis, or by passage of organisms through its gastrointestinal tract. This does not require multiplication or development of the organism. (ii) Biological: propagation (multiplication), cyclic development, or a combination of these (cyclopropagative) is required before the arthropod can transmit the infective form of the agent to humans. An incubation period (extrinsic) is required following infection before the arthropod becomes infective. The infectious agent may be passed vertically to succeeding generations (transovarian transmission); transstadial transmission indicates its passage from one stage of life cycle to another, as nymph to adult. Transmission may be by injection of salivary gland fluid during biting, or by regurgitation or deposition on the skin of feces or other material capable of penetrating through the bite wound or through an area of trauma from scratching or rubbing. This transmission is by an infected nonvertebrate host and not simple mechanical carriage by a vector or vehicle. However, an arthropod in either role is termed a vector.Virulence
the degree of pathogenicity of an organism as evidenced by the severity of resulting disease and the organism’s ability to invade the host tissues.Virus
causative agent of an infectious disease.
derived from, originating in, or being a member of another species.Xenotransplantation
transplantation of an organ, tissue, or cells between two different species (such as a human and a domestic swine).
an infection or infectious disease transmissible under natural conditions from vertebrate animals to humans. May be enzootic or epizootic.