Microbiology 14 Flashcards
Terminology Pathology: Etiology: Pathogenesis: Disease:
Pathology: the study of disease
Etiology: the study of the cause of a disease
Pathogenesis: the development of disease
Infection: colonization of the body by pathogens
Disease: an abnormal state in which the body is not functioning normally
Normal Microbiota:
Transient microbiota
Normal microbiota
Symbiosis
Transient microbiota may be present for days, weeks, or months
Normal microbiota permanently colonize the host
Symbiosis is the relationship between normal microbiota and the host
Symbiosis kinds?
In mutualism, both organisms benefit
In commensalism, one organism benefits, and the other is unaffected
In parasitism, one organism benefits at the expense of the other
Some normal microbiota are opportunistic pathogens
Normal Microbiota:
microbial antagonism
normal microbiota
probiotics
Microbial antagonism is a competition between microbes
Normal microbiota protect the host by
Occupying niches that pathogens might occupy
Producing acids
Producing bacteriocins
Probiotics: live microbes applied to or ingested into the body, intended to exert a beneficial effect
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 laboratory animal.
The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.
Evidence of Infectious Diseases:
sympton, sign and syndrome
Symptom: a change in body function that is felt by a patient as a result of disease
Sign: a change in a body that can be measured or observed as a result of disease
Syndrome: a specific group of signs and symptoms that accompany a disease
Transmission of Infectious Diseases:
Communicable disease,Contagious disease,Noncommunicable 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
Noncommunicable disease: a disease that is not transmitted from one host to another
Occurrence of an Infectious Disease:
incidence,prevalence,sporadic,endemic,epidemic,pandemic
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
Sporadic disease: disease that occurs occasionally in a population
Endemic disease: disease constantly present in a population
Epidemic disease: disease acquired by many hosts in a given area in a short time
Pandemic disease: worldwide epidemic
Herd immunity: immunity in most of a population
Severity or Duration of an Infectious Disease:
acute, chronic,subacute, latent
Acute disease: symptoms develop rapidly
Chronic disease: disease develops slowly
Subacute disease: symptoms between acute and chronic
Latent disease: disease with a period of no symptoms when the causative agent
Extent of Host Involvement in an Infectious Disease:
local,systemic and focal
Local infection: pathogens are limited to a small area of the body
Systemic infection: an infection throughout the body
Focal infection: systemic infection that began as a local infection
Extent of Host Involvement in an Infectious Disease:
sepsis,bacterecemia,septicemia
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: growth of bacteria in the blood
Extent of Host Involvement in an Infectious Disease:
toxemia,viremia,primary infection, secondary infection, subclinical disease
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 (inapparent infection)
Predisposing Factors
Make the body more susceptible to disease Short urethra in females Inherited traits, such as the sickle cell gene Climate and weather Fatigue Age Lifestyle Chemotherapy
Reservoirs of Infection
Continual sources of infection
Human: AIDS, gonorrhea
Carriers may have inapparent infections or latent diseases
Animal: rabies, Lyme disease
Some zoonoses may be transmitted to humans
Nonliving: botulism, tetanus
Soil
Contact
Direct: requires close association between infected and susceptible host
Indirect: spread by fomites
Droplet: transmission via airborne droplets
Vehicle
Transmission by an inanimate reservoir (food, water, air)
Vectors
Arthropods, especially fleas, ticks, and mosquitoes
Transmit disease by two general methods:
Mechanical transmission: arthropod carries pathogen on feet
Biological transmission: pathogen reproduces in vector
Transmission of Disease
