Agent (of disease): Factor such as a microorganism whose presence is essential for the occurrence of a disease.
Anopheles: A genus of mosquitoes that includes all mosquitoes that transmit malaria to humans.
Anopheline: Any of various mosquitoes of the genus Anopheles, which can carry the malaria parasite and transmit the disease to humans.
Anthroponotic: Transmission from human to human and potentially from human to animal.
Antibiotic: Class of substances that can kill or inhibit the growth of some groups of microorganisms. Used in this report to refer to chemicals active against bacteria. Originally antibiotics were derived from natural sources (e.g., penicillin from molds), but many currently used antibiotics are semisynthetic and modified with additions of man-made chemical components. See Antimicrobials.
Antibiotic resistance: Property of bacteria that confers the capacity to inactivate or exclude antibiotics or a mechanism that blocks the inhibitory or killing effects of antibiotics.
Antimicrobials: Class of substances that can destroy or inhibit the growth of pathogenic groups of microorganisms, including bacteria, viruses, parasites, and fungi.
Arboviral diseases: Shortened form of arthropod-borne virus. Any of a group of viruses that are transmitted to man and animals by mosquitoes, ticks, and sand flies; they include such agents as yellow fever and eastern, western, and Venezuelan equine encephalitis viruses.
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.
Asymptomatic: Presenting no symptoms of disease.
Bacteria: Microscopic, single-celled organisms that have some biochemical and structural features different from those of animal and plant cells.
Chagas disease: A potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. Predominantly found in Latin America, T. cruzi is commonly transmitted to humans and other mammals by an insect vector.
Climate: Average meteorological conditions over a specified time period, usually at least a month, resulting from interactions among the atmosphere, oceans, and land surface. Climate variations occur over a wide range of spatial and temporal scales.
Climate change: A change of climate attributed directly or indirectly to human activity that alters the composition of the global atmosphere and is in addition to natural climate variability observed over comparable time periods.
Climate extremes: Used to represent weather extremes (see definition below), but viewed over seasons (e.g., droughts), or longer periods.
Climate variability: Refers to variations or deviations from the mean state of the climate or temporal variations of the atmosphere–ocean system around a mean state measure over a long period of time. Typically, this term is used for time scales longer than those associated with synoptic weather events (i.e., months to millennia and longer). The term natural climate variability is further used to identify climate variations that are not attributable to or influenced by any activity related to humans. However it is recognized that such internal or natural variability could be affected by external factors driving climate change such as changes in the atmospheric concentration of greenhouse gases. The El Niño–Southern Oscillation (ENSO) phenomenon is a good example of the variability in the coupled oceanic and atmosphere system that is a central factor in short-term
climate variability and the interannual time scale (http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/prelude_to_ensofaq.shtml; http://www.ncdc.noaa.gov/paleo/outreach/coral/coralenso.html; http://www.sws.uiuc.edu/atmos/statecli/Climate_change/glossary.htm [accessed March 29, 2016]).
Communicable disease: An infectious disease transmissible (as from person to person) by direct contact with an infected individual or the individual’s discharges or by indirect means (as by a vector).
Dengue/dengue hemorrhagic fever (DHF): A vector-borne viral disease, dengue is transmitted between people by the mosquitoes Aedes aegypti and Aedes albopictus, which are found throughout the world. Dengue fever (DF) is caused by any of four closely related viruses, or serotypes, dengue 1–4. Infection with one serotype does not protect against the others, and sequential infections put people at greater risk for DHF and dengue shock syndrome (DSS).
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.
Ecosystem: Mutually interrelated communities of species and abiotic components, existing as a system with specific interactions and exchange of matter, energy, and information.
El Niño: A warming of the surface waters of the tropical Pacific that occurs every 3 to 5 years, temporarily affecting weather worldwide.
Elimination: Cessation of transmission in a country, continent, or other limited geographic area; complete prevention of a clinical presentation of disease.
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.
Emerging infections: Any infectious disease that has come to medical attention within the last 2 decades or for which there is a threat that its prevalence will increase in the near future (IOM, 1992). Many times, such diseases exist in nature as zoonoses and emerge as human pathogens only when humans come into contact with a formerly isolated animal population, such as monkeys in a rain forest that are no longer isolated because of deforestation. Drug-resistant organisms could also be included as the cause of emerging infections since they exist because of human influence. Some recent examples of agents responsible
for emerging infections include human immunodeficiency virus, Ebola virus, multidrug resistant Mycobacterium tuberculosis, and influenza A (H1N1).
Encephalitis: An acute inflammatory disease of the brain due to direct viral invasion or to hypersensitivity initiated by a virus or other foreign protein.
Endemic: Present in a community or common among a group of people; said of a disease prevailing continually in a region.
Enzootic: A disease of low morbidity that is constantly present in an animal community.
Epidemic: Appearance of an abnormally high number of cases of infection in a given population.
Epidemiology: Study of the distribution and determinants of health-related states or events in specified populations. Epidemiology is the basic quantitative science of public health.
Epizootic: A disease of high morbidity that is only occasionally present in an animal community.
Eradication: Reducing the incidence of a disease to zero worldwide, such that further control measures are unnecessary; total interruption of transmission.
Extreme weather: Refers to weather phenomena that are at the extremes of the historical distribution and are rare for a particular place and/or time, especially severe or unseasonal weather. Such extremes include severe thunderstorms, severe snowstorms, ice storms, blizzards, flooding, hurricanes, high winds, and heat waves. For example, although flooding is common in the United States, the impacts of flooding are not consistent from year to year through time. Many years of small floods with little impact may be followed by a single large flood with a sizable loss (e.g., the June 2008 flooding in the Midwestern United States) (http://www.greenhouse.gov.au/impacts/resources/glossary.html; http://en.wikipedia.org/wiki/Extreme_weather; http://www.sws.uiuc.edu/atmos/statecli/General/Illinois-climate-narrative.htmn [accessed March 29, 2016]).
Extrinsic incubation period: Time required for the development of a disease agent in a vector from the time of uptake of the agent to the time the vector is infective.
Globalization: The increased interconnectedness and interdependence of peoples and countries is generally understood to include two interrelated elements: the
opening of borders to increasingly fast flows of goods, services, finance, people, and ideas across international borders; and the changes in institutional and policy regimes at the international and national levels that facilitate or promote such flows (http://www.who.int/trade/glossary/story043/en/index.html [accessed March 29, 2016]).
Herd immunity: A reduction in the probability of infection that is held to apply to susceptible members of a population in which a significant proportion of the individuals are immune because the chance of coming in contact with an infected individual is less.
Host (disease): Person or other living animal that affords subsistence or lodgment to an infectious agent under natural conditions.
Human African trypanosomiasis (HAT): HAT is a protozoan parasitic disease of people and animals, caused by Trypanosoma brucei and transmitted by the tsetse fly. The disease is endemic in some regions of sub-Saharan Africa, covering about 36 countries and 60 million people.
Incidence: Number of cases of a disease commencing, or of persons falling ill, during a given period of time in a specified population. Incidence rate is the number of new cases of a specific disease diagnosed or reported during a defined interval of time divided by the number of all persons in a defined population during the same time.
Infection: The invasion of the body or a part of the body by a pathogenic agent, such as a microorganism or virus. Under certain conditions the agent develops or multiplies, the results of which may produce injurious effects. Infection should not be confused with disease.
Intermediate host: A host that is normally used by a parasite in the course of its life cycle and in which it may multiply asexually but not sexually.
Kinetoplastid: A group of flagellated protozoa characterized by the presence of one or two flagella in the cell body and a kinetoplast within the mitochondrion. As human parasites, kinetoplastids are associated with Chagas disease, HAT, and leishmaniasis.
La Niña: Cooler-than-normal sea surface temperatures in the central and eastern tropical Pacific ocean that impact global weather patterns. La Niña conditions recur every few years and can persist for as long as 2 years.
Microbe: A microorganism or biologic agent that can replicate in humans (including bacteria, viruses, protozoa, fungi, and prions).
Mitigation: Initiatives that reduce the risk from natural and man-made hazards. With respect to climate change, mitigation usually refers to actions taken to reduce the emissions or enhance the sinks of greenhouse gases.
Morbidity: Diseased condition or state.
Mortality: The quality or state of being mortal; the number of deaths in a given time or place; the proportion of deaths to population.
Outbreak: Localized occurrence as opposed to a generalized epidemic.
Pandemic: Epidemic occurring over a wide geographic area and affecting an exceptionally high proportion of the population.
Parasite: An organism living in, with, or on another organism.
Pathogen: Organism capable of causing disease.
Pathogenic: Capable of causing disease.
Polymerase chain reaction (PCR): A laboratory technique used to make multiple copies of a segment of DNA. PCR is very precise and can be used to amplify, or copy, a specific DNA target from a mixture of DNA molecules.
Prevalence: Proportion of persons in a population currently affected by a particular disease. Prevalence rate is the number of cases of a specific disease at a particular time divided by the population at that time living in the same region.
Protozoa and protozoan parasites: Protozoa are microscopic, unicellular organisms that can be free living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism. Transmission of protozoa that live in a human intestine to another human typically occurs through a fecal–oral route (e.g., contaminated food or water or person-to-person contact). Protozoa that live in the blood or tissue of humans are transmitted to other humans by an arthropod vector (for example, through the bite of a mosquito or sand fly).
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 in which it reproduces itself in such manner that it can be transmitted to a susceptible vector.
Rickettsial disease: Infection caused by a variety of obligate intracellular, Gram-negative bacteria that are usually transmitted by ectoparasites such as fleas, lice, mites, and ticks.
Rift Valley fever: Rift Valley fever is a viral zoonosis that primarily affects animals but also has the capacity to infect humans. Infection can cause severe disease in both animals and humans. The disease also results in significant economic losses due to death and abortion among RVF-infected livestock. The virus was first identified in 1931 after an epidemic struck sheep on a farm in the Rift Valley of Kenya. Since then, outbreaks have been reported in sub-Saharan and North Africa. In 1997–1998, a major outbreak occurred in Kenya, Somalia, and Tanzania, and in September 2000, cases were confirmed in Saudi Arabia and Yemen, marking the first reported occurrence of the disease outside the African continent and raising concerns that it could extend to other parts of Asia and Europe (http://www.who.int/mediacentre/factsheets/fs207/en/ [accessed March 29, 2016]).
RNA interference (RNAi): RNAi is a biological process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules.
rRT-PCR: A real-time polymerase chain reaction is a laboratory technique of molecular biology based on the polymerase chain reaction (PCR), which is used to amplify and simultaneously detect or quantify a targeted DNA molecule.
Salmonella: A genus of bacteria that cause typhoid fever, food poisoning, and enteric fever from food poisoning.
Species barrier: Difficulty or impossibility for an infectious agent to pass from one species to another (due to differences between species).
Subclinical infection: An infection where the patient does not have any apparent symptoms (also known as an asymptomatic infection).
Syndrome: A group or recognizable pattern of symptoms or abnormalities that indicate a particular trait or disease.
Transmission: Process by which a pathogen passes from a source of infection to a new host.
Universal precautions: The use of gloves, protective garments, and masks when handling potentially infectious or contaminated materials.
Vaccine: A preparation of living, attenuated, or killed bacteria or viruses, fractions thereof, or synthesized or recombinant antigens identical or similar to those found in the disease-causing organisms that are administered to raise immunity to a particular microorganism.
Vector: A carrier—especially an arthropod—that transfers an infective agent from one host (which can include itself) to another.
Vector-borne: Transmitted from one host to another by a vector.
Vector-borne disease: (1) Mechanical: this 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. (2) 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 the 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 the bite wound or 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.
Viremia: The presence of virus in the blood of a host.
Virulence: The ability of any infectious agent to produce disease. The virulence of a microorganism (such as a bacterium or virus) is a measure of the severity of the disease it is capable of causing.
Xylem: The vascular tissue in plants that conducts water and dissolved nutrients upward from the root and also helps to form the woody element in the stem.
Zika virus: ZIKV is a member of the Flaviviridae virus family and the Flavivirus genus. In humans, it causes a disease known as Zika fever. It is related to dengue, yellow fever, and West Nile and Japanese encephalitis, viruses that are also members of the virus family Flaviviridae.
Zoonoses: Microbes that are naturally transmitted between animals and humans that cause disease in human populations but can be perpetuated solely in nonhuman host animals (e.g., influenza, rabies).
Zoonotic infection: Infection that causes disease in human populations but can be perpetuated solely in nonhuman host animals (e.g., bubonic plague); may be enzootic.