Edit · Interactions Between Microbes and Humans (VOCABULARY STUDY)

Pathology

The study of disease

Etiology

The study of the cause of a disease

Pathogensis

The development of a disease

Infection

The successful colonization of the body by pathogens

Disease

Any condition in which the normal structure or functions of the body are damaged or impaired

What is the sequence from exposure to disease?

Exposure > Colonization > Infection > Disease

Does exposure or colonization always lead to disease?

No

Transient microbiota

are present for days, weeks, or months

Normal microbiota

permanently colonize the host

Symbiosis

is the relationship between normal microbiota and the host - MUTUALISM, COMMENSALISM, PARASITISM

Normal microbiota protect the host by

occopying niches that pathogens might occupy, producing acids, producing bacteriocins

Symptom

a subjective change in a body function that is felt by a patient because of a disease

Sign

An objective and measurable change in body function as the result of a disease.

Syndrome

a specific group of signs and symptoms that accompany a disease

Communicable disease

a disease that is spread from one host to another

Contagious disease

a disease that is easily spread from one host to another

Iatrogenic disease

contracted as the result of a medical procedure

Noncommunicable disease

a disease that is not transmitted from one host to another

True pathogens

capable of causing disease in healthy persons with normal immune defenses

Opportunistic pathogens

cause disease when the host's defenses are compromised

Virulence of a microbe is determined by

its ability to estaablish itself in a host and cause damage

Virulence factor

contributes to its ability to establish itself in the host and cause damage

Endemic disease

disease constantly present in a population

Sporadic disease

disease that occurs occasionally in a population

Epidemic disease

disease acquired by many hosts in an area in a short time

Pandemic disease

worldwide epidemic

Herd immunity

immunity in most of a population

Incidence

fraction of a population that contracts a disease during a specific time

Prevalence

fraction of a population having a specific disease at a given time

Acute disease

symptoms develop rapidly

Chronic (persistent) disease

develops slowly

Subacute disease

symptoms between acute and chronic

Latent disease

disease with a period of no symptoms when the causative agent is inactive

Local infection

pathogens are limited to a small area of the body

Focal infection

a localized pathogen, or the toxins it produces, can spread to a secondary location

Systemic infection

an infection throughout the body

Sepsis

toxic inflammatory condition arising from the spread of microbes

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 (inapparent infection)

Bacteremia

bacteria in the blood

Sepsis

growth of bacteria in the blood

Toxemia

toxins in the blood

Viremia

viruses in the blood

Reservoir

a primary habitat in the natural world from which a pathogen originates

Examples of a reservoir

living: humans with active infections, human carriers, animals and anthropods/ non-living: soil, water, food, and air

Transmitter

an individual or object from which an infection is acquired

vehicle transmission

transmission by an inanimate reservoir (food, water,air)

DIRECT contact

requires a close association between the infected and susceptible host

INDIRECT contact

spread by fomites

DROPLET contact

transmission via airborne droplets

Vector

usually an anthropod,

Mechanical Vector

anthropod carries pathogen on feet

Biological Vector

pathogen reproduces in vector

ID50

infectious dose for 50% of the test population

LD50

lethal dose (of a toxin) for 50% of the test population

What are the three portals of entry?

Skin, Inhalation, Ingestion

Adhesins/Ligands

bind to the receptors on host cells

M protein

resists phagocytosis

Mycolic acid

(waxy lipid) resists digestion

Toxin

substance that contributes to pathogenicity

Toxigenicity

ability to produce a toxin

Toxemia

presence of toxin in the host's blood

Toxoid

inactivated toxin used in a vaccine

Antitoxin

antibodies against a specific toxin

What are the major portals of exit of infectious diseases?

Coughing, sneezing, insect bite, removal of blood, feces, skin cells and open lesions, urine