Topic 10 -Principles of Disease and Epidermiology Flashcards
What is pathology?
Study of disease
What is etiology?
Study of the cause of a disease
What is pathogenesis?
The development of a disease
What is infection?
Colonisation of the body by pathogens
What is disease?
An abnormal state in which the body is not functioning normally
Transient microbiota…?
may be present for days, weeks or months
A bit about normal microbiota? How do they protect the host?
Permanently colonise the host. Can be opportunistic pathogens.
Protect by:
-producing acids, -producing bacteriocins, -occupying niches that pathogens might occupy
What is symbiosis? Name the 3 kinds.
the relationship b/w normal microbiota and the host
-commensalism, mutualism, parasitism
What is commensalism?
one organism benefits, and the other is unaffected e.g. a whale and barnacles
What is mutualism?
both organisms benefit e.g. oxpeckers (birds) and zebras
What is parasitism?
one organism benefits at the expense of another e.g. tapeworms in humans/animals
List Koch’s Postulates.
- The same pathogen must be present in every case of the disease
- The pathogen must be isolated from the diseased host and grown in pure culture
- The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible animal
- The pathogen must be isolated from the inoculated animal and must be shown to be the same as in the original animal
Koch’s Postulates are used to prove..?
the cause of an infectious disease
What is a communicable disease?
A disease that is spread from one host to another e.g. HIV
What us a noncommunicable disease?
A disease that is not transmitted from one host to another
What is a contagious disease?
A disease that is easily spread from one host to another e.g. flu
What is a symptom?
A change in body function that is felt by a patient as a result of disease (can only be experienced) e.g. pain
What is a sign?
A change in a body that can be measured or observed as a result of disease e.g. rapid pulse, high temp.
What is a syndrome?
A specific group of signs and symptoms that accompany a disease
Describe incidence of disease
Fraction (annual number) of a population that contracts a disease during a specific time
Describe prevalence of disease
Fraction (current number) of a population having a specific disease at a given time
Describe sporadic disease
Disease that occurs occasionally in a population
Describe endemic disease
Disease constantly present in a population
Describe epidemic disease
Disease acquired by many hosts in a given area in a short time
Describe pandemic disease
Worldwide epidemic
What is herd immunity?
Immunity in most of a population
What is an acute disease?
symptoms develop rapidly
What is a chronic disease?
disease develops slowly
What is a subacute disease?
Symptoms b/w acute and chronic
What is a latent disease?
Disease w/ a period of no symptoms when the causative agent is inactive
What is a local infection?
Pathogens are limited to a small area of the body
What is a systemic infection?
An infection throughout the body
What is a focal infection?
A systemic infection that began as a local infection
What is sepsis?
Toxic inflammatory condition arising from the spread of microbes
What is bacteremia and septicemia?
Bacteremia - bacteria in the blood
Septicemia - growth of bacteria in the blood
What is toxemia and viremia?
toxemia - toxins in the blood
viremia - viruses in the blood
Describe a primary infection
Acute infection that causes the initial illness
Describe a secondary infection
Opportunistic infection after a primary (predisposing) infection
What is a subclinical disease?
No noticeable signs or symptoms (inapparent infection)
What is a predisposing factor to disease? List 4.
Make the body more susceptible to disease.
- Inherited traits e.g. sickle cell
- Climate & weather
- Short urethra in females
- Age & lifestyle
Put the following in order, according to the pattern of disease: period of decline, period of convalescence, period of illness, prodromal period, incubation period
SEE DIAGRAM.
- Incubation period (no signs or symptoms)
- Prodromal period (mild signs or symptoms)
- Period of illness (most severe signs and symptoms)
- Period of decline (signs and symptoms)
- Period of convalescence (gradual recovery of health and strength after illness or injury)
What is a reservoir of infection? Give examples.
A continual source of infection. Carriers may have inapparent infections or latent diseases
Human -AIDS
Animal -Rabies
Nonliving -fomites, soil, air, dust, food
What is a fomite?
an inanimate object capable of transmitting pathogens
Describe 3 methods of disease transmission
- Contact (direct, indirect by fomites, airborne droplets)
- Vehicle transmission (by inanimate reservoir e.g. food)
- Vectors e.g. fleas
What are the 2 methods of disease transmission by vectors?
- Mechanical transmission: carries pathogen on feet
2. Biological transmission: pathogen reproduces in vector
What is a nosocomial infection?
Acquired as a result of a hospital stay
List several methods of disease transmission in hospitals
- bedding
- patients gowns
- towels
- bedpans
- thermometers
- gloves
- eating/drinking utensils
What is a compromised host?
a patient with acquired or congenital immunologic deficiency at increased risk for infectious disease complications
