The disease‐producing potential of a microorganism. Often defined in terms of virulence factors, which are specific characteristics or abilities of the microorganism.
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 ability of an organism to sicken or kill its host.
Ability or power of a microorganism to produce disease.
The capacity of a given organism or group of organisms to produce disease of various degrees of severity.
The capacity of a microorganism to overcome the body’s immune system and other defenses and cause disease. Virulence is increased when disease causing agents have special characteristics, called virulence factors, which contribute to the agent’s ability to survive in the human body. Certain signals can sometimes control the growth of the virulence factors; for example, oxygen, pH, and temperature levels and the concentration of ions are among the signals that influence the virulence factors of bacteria.
The disease-producing (pathogenic) ability of a microorganism.
The power of a bacterium or virus to cause disease. Virulence can be measured by how many people the micro-organism infects, how quickly it spreads through the body, and how many people die from it.
The relative power and degree of pathogenicity possessed by organisms. Properties that influence the virulence of an organism include 1. the strength of its adhesion molecules, which link it to the target cell; 2. its ability to secrete enzymes or exotoxins that damage target cells, or endotoxins that interfere with the body’s normal regulatory systems; and 3. its ability to inhibit or evade the actions of white blood cells and their chemical mediators.
The concept known as “pathogenicity” refers to the relative ability of a parasitic organism or virus to cause disease within an organism. This capacity to induce illness can vary in degree, and is often used to measure the harmful impact of a particular pathogen.
The measure of an infectious agent’s capacity to cause illness, as determined by factors such as the mortality rate and its ability to infiltrate the host’s tissues, defines the pathogenicity of the organism.
The capacity of a microorganism to induce illness. This can be evaluated by determining the percentage of the population exposed to the microorganism that experiences disease symptoms, the speed at which the infection propagates within the body, or the fatality rate associated with the infection.