Microbiology & Parasitology M4

Fix

Normal Microbiota

Microorganisms that normally reside in or on the human body without causing disease

Resident Flora

Permanent members of the microbiota that reestablish after disturbance

Transient Flora

Temporary microorganisms present for short durations

Commensalism

One organism benefits, the other is unaffected; 

Mutualism

Both organisms benefit from each other

Parasitism

One organism benefits at the expense of the host

Opportunistic Pathogens

Normally harmless microbes that cause disease when the host is weakened

Signs

Objective changes in health measurable by a physician (e.g., fever)

Symptoms

Subjective changes felt by the patient (e.g., pain)

Communicable Disease

Disease that spreads from one person to another

Non

Communicable Disease

Incidence

Number of new cases in a population

Prevalence

Total number of cases (old and new) in a population

Sporadic Disease

Disease occurring occasionally

Endemic Disease

Disease constantly present in a population

Epidemic Disease

Sudden increase in disease cases in a region

Pandemic Disease

Worldwide outbreak of a disease

Acute Disease

Rapid onset, short duration

Chronic Disease

Slow development, long duration

Latent Disease

Pathogen remains inactive, then reactivates later

Local Infection

Confined to a small area of the body

Systemic Infection

Spread throughout the body

Primary Infection

Initial acute infection

Secondary Infection

Caused by an opportunistic pathogen after primary infection

Pathogen

Microorganism that causes disease

Reservoir

Natural habitat of a pathogen (human, animal, soil, water)

Carrier

Person who harbors and transmits a pathogen without symptoms

Portal of Entry

Pathway by which a pathogen enters the host (e.g., respiratory tract)

Portal of Exit

Pathway by which a pathogen leaves the host

Mode of Transmission

Method by which a pathogen is spread (contact, vehicle, vector)

Virulence

Degree of pathogenicity of an organism

Virulence Factors

Features enabling microorganisms to cause disease (e.g., pili, capsule, toxins)

Pili (Fimbriae)

Hair

Capsule

Gelatinous layer aiding in adhesion and protecting from phagocytosis

Flagella

Appendages aiding in motility and contributing to virulence

Toxins

Poisonous substances produced by microbes

Exotoxin

Protein secreted by bacteria, highly toxic, antigenic, heat

Endotoxin

Lipopolysaccharide in Gram