Learning activity 7

Symptoms

changes in body function that are felt by a patient as a result of disease (Ex: feeling feverish)

Signs

changes in a body that can be measured or observed as a result of disease (ex: fever of 102.2 * F)

Disease

an abnormal state in which the body is not performing normal functions

Subclinical disease

no noticeable signs or symptoms (inapparent infection)

Infection

invasion or colonization of the body by pathogens

Acute disease

Symptoms develop rapidly, but the disease lasts only a short time

Subacute disease

intermediate between acute and chronic

Chronic disease

symptoms develop slowly

Latent disease

causative agent is inactive for a time, but then activates and produces symptoms

Local infection

pathogens are limited to a small area of the body

Focal infection

systemic infection that began as a local infection

Systemic (generalized) infection:

an infection throughout the body

Sepsis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

Bacteremia

bacteria in the blood

Septicemia

also known as blood poisoning; growth of bacteria in the blood

Toxemia

toxins in the blood

Viremia

viruses in the blood

Primary infection

acute infection that causes the initial illness

Secondary infection

opportunistic infection after a primary (predisposing) infection

Subclinical disease

No noticeable signs or symptoms (asymptomatic)

Incubation period

interval between initial infection and first signs and symptoms

Prodromal period

short period after incubation; early, mild, symptoms

Period of illness

disease is most severe

Period of decline

signs and symptoms subside

Period of convalescence

body returns to its pre-diseased state

Pathogenicity

the ability to cause disease

Virulence

the degree of pathogenicity

Microbes form __

biofilms

virulence factors

help pathogens spread throughout the body

Exoenzymes

rearrange actin filaments of the cytoskeleton, allowing bacteria to move between cells

Siderophores

proteins secreted by pathogens that bind iron more tightly than host cells

Toxins

Poisonous substances produced by microorganisms. (Produce fever, cardiovascular problems, diarrhea, and shock)

Toxemia

presence of toxin in the host’s blood

Intoxications

presence of toxin in the host’s blood

Toxigenicity

ability of a microorganism to produce a toxin

Superantigens

cause an intense immune response due to the release of cytokines from host cells

Genotoxins

Damage DNA (causing mutations disrupting cell division and leading to cancer), produced by SOME gram-negative bacteria

Lipid A

portion of lipopolysaccharides (LPS) of gram-negative bacteria, released during bacterial multiplication and when gram-negative bacteria die

Exotoxins

mostly from gram-positive bacteria, metabolic product of the cell, made of protein, small lethal dose, destroyed by autoclave

Endotoxins

Gram-negative only, part of cell structure, released when cell divides/dies, made of lipid, general symptoms, not destroyed by autoclave, causes fever, large lethal dose

Antigenic drift

minor changes in surface antigens

Antigenic shift

Major changes in surface antigens

Cytopathic effect (CPE)

stopping cell synthesis, causing cell lysosomes to release enzymes, changing host cell function, producing interferons to protect uninfected cells

Inclusion bodies

created by viruses

Syncytium

created by a virus fusing cells

Contact inhibition

Viruses cause loss of contact inhibition in the cell, leading to cancer.

Mycotoxins

produced by mushrooms and are neurotoxic

etiology

proved by Koch’s postulates

Endemic

disease constantly present in a population

Sporadic

disease that occurs only occasionally

Epidemic

disease acquired by many people in a given area in a short time

Pandemic

worldwide epidemic

communicable disease

a disease that is spread form one host to another

noncommunicable disease

a disease that is not spread from one host to another

Contagious disease

diseases that are easily and rapidly spread from one host to another

Noninfectious diseases

not caused by a pathogen

nosocomial disease (HAIs: Healthcare-Associated infections)

acquired while receiving treatment in a healthcare facility

Compromised host

an individual whose resistance to infection is impaired by disease, therapy, or burns

Zoonotic disease (zoonoses)

pathogen that is transmitted from animals to humans

Opportunistic pathogens

Do not cause disease in a normal habitat or in a healthy individual

Emerging infectious diseases (EIDs): New diseases

may be new to an area due to transportation/environmental factors

EIDS (diseases that have changed)

able to infect a new host or has become resistant to treatment

Human reservoirs

carriers may have inapparent infections or latent diseases

Animal reservoirs

Zoonoses are diseases transmitted from animals to humans

Nonliving reservoirs

Soil and water

Direct contact transmission

requires close association between the infected and a susceptible host

Indirect contact transmission

spreads to a host by a nonliving object called a fomite

Droplet transmission

transmission via airborne droplets less than 1 meter

Vehicle transmission

transmission by an inanimate reservoir

Mechanical transmission

arthropod carries pathogen on its feet

biological transmission

The pathogen reproduces in the arthropod vector and is transmitted via bites or feces

Notifiable infectious diseases

diseases in which physicians are required to report occurrence