Lecture 6.2: Mechanisms of Pathogenicity

Infection

Successful colonization within a host of a microorganism (bacterium, virus, fungi, etc…), leading to signs and symptoms deviating from the host's normal structure or functioning.

Pathogens

Microorganisms that can cause disease.

Signs of Disease

Objective and measurable indications of a disease in humans, such as body temperature, heart rate, breathing rate, and blood pressure.

Symptoms of Disease

Subjective experiences that may not be objectively measured.

Portal of Entry

The pathway through which a pathogen enters a susceptible host.

Periods of Disease

Sequential stages including Incubation, Prodromal, Period of Illness, Period of Decline, and Period of Convalescence in acute diseases.

Pathogenicity

The ability of a microbe to cause disease.

Virulence

The degree to which an organism is pathogenic, indicating the severity of disease signs and symptoms.

Primary Pathogens

Microorganisms causing disease regardless of the host's immune system effectiveness.

Opportunistic Pathogens

Microorganisms causing disease only in individuals with compromised host defenses.

Virulence Factors

Molecules aiding pathogens in colonizing the host, evading the immune response, obtaining nutrition, and causing damage to host tissues.

Antigenic Variation in Viruses

Changing surface antigens to avoid recognition by the host's immune system.