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the ability of an agent to enter and multiply in the host is known as

infectious agents

any type of pathogens that can cause a disease


any disease-producing agent (especially a virus or bacterium or other microorganism)


ability of a pathogen to overcome the defensive powers of a host and to induce disease


extreme harmfulness (as the capacity of a microorganism to cause disease)


rate of occurrence; particular occurrence; Ex. high incidence of infant mortality


the number of existing cases of a disease


organism that carries pathogens from person to person


anything (a person or animal or plant or substance) in which an infectious agent normally lives and multiplies


an animal or plant that nourishes and supports a parasite


a disease that can pass from animals to humans


a disease that is constantly present to a greater or lesser degree in people of a certain class or in people living in a particular location


The state where the disease is continuously present in a population of animals with no serious outbreaks


a widespread outbreak of an infectious disease


a disease spreading quickly among animals


an epidemic that is geographically widespread


Animal version of pandemic.

mechanical transmission

indirect transmission by a vector in which the infectious agent does not undergo physiologic changes inside the vector

biological transmission

The transmission of a pathogen from one host to another when the pathogen reproduces in the vector.




life cycle events triggered by environmental cues may be altered. trees "leaf out" earlier. spring arrives earlier in some places. flowers appearing out of season

transovarial transmission

when the infection is transmitted by stages from generation to generation of ticks

vector competence

ability of a vector to acquire a pathogen and to successfully transmit it to another susceptible host

sibling species

Reproductivly isolated species that are so similar morphologically that they are difficult or impossivle to distinguish using morphological characters


being long-lasting and recurrent or characterized by long suffering adjective


having or experiencing a rapid onset and short but severe course


any substance (as a toxin or enzyme) that stimulates the production of antibodies


any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response

herd immunity

Immunity in most of a population


a population survey using serologic test to screen for exposure and immunity to an infectious disease

active immunity

a form of acquired immunity in which the body produces its own antibodies against disease-causing antigens

passive immunity

an immunity resulting from antibodies that are conveyed naturally through the placenta to a fetus or artificially by injection of a serum containing antibodies


reduced in strength

subunit vaccine

Contain only certain proteins from the organism, can not cause dz, a lyme vaccine and FeLV are available

Vaccinia virus

Virus used to vaccinate against variola


a watch kept over a person; careful, close, and disciplined observation


animals with detectable antibodies


a system of refrigeration used for keeping and distributing vaccines at the correct temperature and in good condition

genetic control

Chemical barriers, physical barriers, & sterile males


primary prevention of infectious diseases by administering antimicrobial drugs to prevent infection


the working together of two things (muscles or drugs for example) to produce an effect greater than the sum of their individual effects


a toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die


toxin that is secreted by microorganisms into the surrounding medium


non membrane bound nucleus


relating to the stage in the development of a disease before the symptoms are observed

epidemiological triad

agent, host, environment


any sensation or change in bodily function that is experienced by a patient and is associated with a particular disease


a property of molecules to which an adaptive immune response can be generated

risk factor

anything that increases the chance of disease or injury


a bacterial toxin that has been weakened until it is no longer toxic but is strong enough to induce the formation of antibodies and immunity to the specific disease caused by the toxin

passive immunization

injection of pre-formed abs into patient (can be from another species or maternal abs)

active immunization

exposing susceptible individuals to antigens associated with an infectious disease process that do not cause the disease but rather induce an immune response that protects against subsequent infection

intrinsic factor

•natural substance normally found present in the stomach essential to the metabolism of vitamin B 12 .

extrinsic factor

Body coverings


Able to be transmitted between people or species; contagious or catching; talkative or expansive; readily communicated

droplet nuclei

particles of dried secretions from the mouth and nose that may float in the air for a considerable amount of time over long distances


any inanimate object (as a towel or money or clothing or dishes or books or toys etc.) that can transmit infectious agents from one person to another

transovarial transmission

•The transmission of microorganisms between generations of hosts via the eggs

asymptomatic carrier

a person infected with a pathogenic microorganism but with no symptoms of the infection

incubatory carrier

An individual capable of transmitting an infectious agent to others during the incubation period of the disease.

convalescent carrier

An individual capable of transmitting an infectious agent to others during the incubation period of the disease

chronic carrier

person with a latent infection who sheds the infectious agent


the ratio of deaths in an area to the population of that area


death rate

natural immunity

immunity to disease that occurs as part of an individual's natural biologic makeup

acquired immunity

Formation of antibodies and lymphocytes after exposure to an antigen


long term or permanent damage to the host long after the disease leaves the host

incubation period

the period between infection and the appearance of symptoms of the disease

attack rate

type of incidence rate defined as the proportion of persons exposedto an agent who develops the disease, usually for a limited time in a specific population

relative risk

incidence of disease (mortality) in exposed over incidence of disease in unexposed

prospective study

data collected in the future from groups sharing common factors

retrospective study

study that begins with the identification of persons with the disease and a suitable comparison (control) group of persons without the disease, then compares the diseased and nondiseased with reguard to the frequency of exposure to study factor

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