Chapter 14- infection, infectious diseases, and epidemiology

Resident microbiota

Part of the normal microbiota throughout life

Transient microbiota

Remain in the body for a short period, found in the same regions as resident microbiota, cannot persist in the body because of competition

Axenic

Development in womb free of microorganisms

Opportunistic pathogens

Normal microbiota that cause disease under certain circumstances

Reservoirs of Infectious diseases

Sites where pathogens are maintained as a source of infection. Three types: Animal, Human, and Nonliving

Zoonoses

Diseases naturally spread from animal host to humans

Human carriers

Infected individuals who are asymptomatic but infective to others

Contact transmission

Direct , indirect , and droplet

Direct transmission

Handshaking, kissing, sexual intercourse, bites

Indirect transmission

Drinking glasses, toothbrushes, toys, punctures

Droplet transmission

Droplets from sneezing withing 1 meter

Vehicle transmission

Airborne, waterborne, foodborne

Airborne transmission

Dust particles or droplets carried more than 1 meter

Waterborne transmission

Streams and swimming pools

Foodborne transmission

Poultry, seafood, meat

Vector transmission

Mechanical or biological

Mechanical transmission

On bodies of flies or roaches, they are not infected with it, just carrying it

Biological transmission

Lice, mites, mosquitos, ticks

Portals of entry and exit

Sites through which pathogens enter or exit the body

Examples: Skin, mucous membranes, placenta, parenteral route

Adhesion

Process in which microorganisms attach themselves to cells

Disease (morbidity)

Invading pathogen alters normal body functions

Symptoms

Subjective characteristics of disease felt only by the patient

Signs

Objective manifestations of disease observed or measured by others

Syndrome

Symptoms and signs that characterize a disease or abnormal condition

Asymptomatic (Subclinical)

Infections that lack symptoms but may still have signs of infection

Pathogenicity

Ability of a microorganism to cause disease

Virulence

Degree of pathogenicity

Incubation period

no signs or symptoms

Prodromal period

Vague, general symptoms

Illness

Most severe signs and symptoms

Decline

Declining signs and symptoms

Convalescence

No signs or symptoms

Acute disease

Disease in which symptoms develop rapidly and that runs its course quickly

Chronic disease

Disease with usually mild symptoms that develop slowly and last a long time

Subacute disease

Disease with time course and symptoms between acute and chronic

Asymptomatic disease

Disease without symptoms

Latent disease

Disease that appears a long time after infection

Communicable disease

Disease transmitted from one host to another

Noncommunicable disease

Disease arising from outside of hosts or from opportunistic pathogen

Contagious disease

Communicable disease that is easily spread

Local infection

Infection confined to a small region of the body

Systemic infection

Widespread infection in many systems of the body; often travels in the blood or lymph

Focal infection

Infection that serves as a source of pathogens for infections at other sites in the body

Primary infection

Initial infection within a given patient

Secondary infection

Infections that follow a primary infection; often by opportunistic pathogens