Infection
Invasion/colonization of body by pathogenic microorganisms
Disease
Occurs when infection results in change from normal state of health
Pathogen
Microorganism/virus able to produce disease
Location of portal exit
Usually close to organism’s breeding site
Transmission of disease pathway
(1) Reservoir
(2) Portal of exit
(3) Mode of transmission
(4) Portal of entry
(5) Susceptible victim
Factors for infection
(1) Communicability
(2) Immunogenicity
(3) Pathogenicity
(4) Toxingenicity
(5) Virulence
Risk factors for susceptibility
Breaking the chain of infection
Stages of infection
(1) incubation period
(2) prodromal stage
(3) invasion/acute illness
(4) convalescence
Classes of infectious microorganisms
Symbiosis
benefits only the host not the organism
Mutualism
benefits host and microorganism
Commensalism
benefits only the microorganism, no harm to host
Pathogenicity
benefits the microorganism, harms the host
Opportunism
Benign microorganisms become pathogenic due to decreased host resistance or translocation to other body sites
Bacteria characteristics
Bacterial virulence factors
Bacteremia
presence of bacteria in the blood
Sepsis
large amount of infection in the blood
life-threatening
overproduction of pro-inflammatory cytokines
Most common bacterial infections
Reproduction of fungi
Mycoses
infections caused by fungi
Dermatophytes
fungi that invade skin, hair, or nails
Candida albicans
most common cause of fungal infection
opportunistic yeast