Module 11

Pathogenesis

Pathogenesis

The mechanisms involved in the development and progression of a disease.

Localized Infection

An infection where the pathogens are contained at the original site of infection.

Systemic Infection

An infection that has spread throughout the body, affecting multiple systems.

Primary Infection

The first disease in cases where one infectious disease may follow another. It affects healthy individuals.

Secondary Infection

The second disease that affects infected individuals.

Incubation Period

The time that elapses between the arrival of the pathogen and the onset of symptoms.

Prodromal Period

The time during which the patient feels "out of sorts" but is not yet experiencing actual symptoms of the disease.

Period of Illness

The time during which the patient experiences the typical symptoms associated with a particular disease.

Convalescent Period

The time during which the patient recovers from the illness.

Virulence

The degree or measure of pathogenicity of an organism.

Virulence Factors

The physical attributes or properties of pathogens that enable them to escape host defense mechanisms and cause disease.

Attachment

The process by which pathogens anchor themselves to host cells.

Exoenzymes

Enzymes released by pathogens that enable them to evade host defense mechanisms, invade, or cause damage to body tissues.

Endotoxins

Toxins that are integral parts of the cell walls of Gram-negative bacteria and can cause adverse physiological effects.

Exotoxins

Toxins produced by pathogens that are secreted and can cause damage to specific target organs or systems.

Necrotizing Agent

Cells or tissue death which is also called necrosis.

Coagulase

It is the fibrin covering. It is released by certain species of streptococcus, therefore being able to resist phagocytosis and impair immune response.

Kinase

It is the clot dissolution or lysis. Blood clots prevent the bacteria from moving and attaching.

Hyaluronidase and Collagenase

Spread through connective tissue.

Hemolysins

It is for RBC lysis.

Lecithinase

It is for phospholipid breakdown.

Neurotoxins

The most potent exotoxin that affects the central nervous system; affect neurotransmission.

Enterotoxins

Toxins that affect the gastrointestinal tract, often causing diarrhea and vomiting.

Erythrogenic Toxins

Toxins that produced by some strains of Streptococcus pyogenes, causes scarlet fever that affects RBCs.

Leukocidins

Toxins that destroy white blood cells. They cause destruction of every cells that the body sends to the site of infection to ingest and destroy pathogens.

Diphtheria Toxins

They are produced by toxigenic strains of Corynebacterium diphtheriae. The enzymes inhibit protein synthesis. It kills mucosal epithelial cells and phagocytes and adversely affects the heart and nervous system.

Antigenic Variation

The ability of pathogens to change the composition of their surface antigens, evading recognition by the immune system.

Camouflage and Molecular Mimicry

Mechanisms used by pathogens to mimic host cell surface molecules, making them less recognizable as foreign by the immune system.

Antibody Destruction

The production of enzymes by pathogens that destroy antibodies, rendering them ineffective in fighting the infection.