Lecture 13 Flashcards
What is pathology?
study of disease
What is etiology?
cause of a disease
What is pathogenesis?
development of disease
What is an infection?
invasion or colonization of the body by pathogens
What is a disease?
abnormal state in which the body is not performing normal functions
When the human microbiome start?
in utero
- through placenta and maternal cut
How is the human microbiome affected?
microbial diversity increases through interactions with the environment and the diet
- stabilizes throughout life but plays key role in digestion, immunity, and health
What is the human microbiome project?
analyzes relationships between microbial communities on the body and human health
What is normal microbiota?
permanently colonize the host and do not cause disease under normal conditions
What is transient microbiota?
temporarily present
What is the distribution and composition of normal microbiota determined by?
- nutrients
- physical and chemical factors
- host defenses
- mechanical factors
What bacteria is present during vaginal birth?
lactobacillus and bacteroides
What bacteria is present during c-section?
staphylococcus aureus
What is microbial antagonism?
competition between microbes
- competitive exclusion
How does the normal microbiota protect the host?
- competing for nutrients
- producing substances harmful to invading microbes
- affecting pH and available oxygen
What is symbiosis?
relationship between normal microbiota and the host
What is commensalism?
one organism benefits and the other is unharmed
What is mutualism?
both organisms benefit
What is parasitism?
one organism benefits and the other is harmed
What are Koch’s Postulates?
1) Same pathogen must be present in every case of the disease
2) Pathogen must be isolated from the diseased host and grown in pure culture
3) Pathogen from the pure culture must cause the disease when it’s inoculated into a health, susceptible laboratory animal
4) Pathogen must be isolated from the inoculated animal and must be shown to be the original organism.
Why did Koch form those postulates?
to prove the cause of an infectious disease
What are some exceptions to Koch’s postulates?
- some pathogens can cause several disease conditions
- some pathogens cause disease only in humans
- some microbes have never been cultured
What are symptoms?
changes in body function that are felt by a patient as a result of disease
What are signs?
changes in a body that can be measured or observed as a result of disease
What is a syndrome?
specific group of signs and symptoms that accompany a disease
What is a communicable disease?
a disease that is spread from one host to another
What is a contagious disease?
disease that are easily and rapidly spread from one host to another
What is a noncommunicable disease?
disease that is not spread from one host to another
What is an incidence?
number of people who develop a disease during a particular time period
What is prevalence?
number of people who develop a disease at a specified time, regardless of when it first appeared
- takes into account both old and new cases
What is a sporadic disease?
occurs only occasionally
What is an endemic disease?
constantly present in a population
What is an epidemic disease?
acquired by many people in a given area in a short time
What is a pandemic disease?
worldwide epidemic
What is an acute disease?
symptoms develop rapidly and the disease lasts a short time
What is a chronic disease?
symptoms develop slowly
What is a subacute disease?
intermediate between acute and chronic
What is a latent disease?
causative agent is inactive for a time and then activates and produces symptoms
What is herd immunity?
immunity in most of a population
What is local infection?
pathogens are limited to a small area of the body
What is a systemic infection?
infection throughout the body
What is a focal infection?
systemic infection that began as a local infection
What is sepsis?
toxic inflammatory condition arising from the spread of microbes from a focus of infection
- bacteria or their toxins
What is bacteremia?
bacteria in the blood
What is septicemia?
blood poisoning
- growth of bacteria in the blood
What is toxemia?
toxins in the blood
What is viremia?
viruses in the blood
What is primary infection?
acute infection that causes the initial illness
What is secondary infection?
opportunistic infection after a primary infection
What is subclinical disease?
no noticeable signs or symptoms
What are some predisposing factors?
- gender
- inherited traits
- climate/weather
- lack of vaccination
- fatigue
- age
- lifestyle
- nutrition
What is incubation period?
interval between initial infection and first signs and symptoms
What is prodromal period?
shor tperiod after incubation
- early, mild symptoms
What is period of illness?
disease is most severe
What is period of decline?
signs and symptoms subside
What is period of convalescence?
body returns to its prediseased state
What are examples of continual sources of infection?
- human reservoirs
- animal reservoirs: animals -> humans
- nonliving reservoirs: soil and water -> inhaled by humans
What are examples of contact transmission?
- direct contact: close association between infected and susceptible host
- congenital transmission: mother to fetus/newborn
- indirect contact: fomite (nonliving object like doorknob)
- droplet transmission: airborne droplets less than 1 meter
What are examples of transmission by an inanimate reservoir?
- airborne
- waterborne
- foodborne
What are healthcare-associated infections? (HAIs)
acquired while receiving treatment in a healthcare facility
- AKA nosocomial infections
What do HAIs result from?
- microorganisms in the hospital environment
- weakened status of the host
- chain of transmission in a hospital
What is a compromised host?
individual whose resistance to infection is impaired by disease, therapy, burns
What are transmission-based precautions?
supplemental to standard precautions
- designed for known or suspected infections
- masks
What are examples of standard practices?
- handwashing
- disinfecting tubs used to bathe patients
- cleaning instruments well
- using disposable bandages and intubation
What are emerging infectious diseases?
diseases that are new, increasing in incidence, or showing a potential to increase in the near future
What are contributing factors of emerging infectious diseases?
- genetic recombination
- evolution of new strains
- widespread use of antibiotics and pesticides
- changes in weather patterns
- modern transportation
- insect vectors
- ecological disaster, war, and expanding human settlement
- animal control measures
- public health failure
- bioterrorism
What is epidemiology?
study of where and when diseases occur and how they are transmitter in populations
What do epidemiologists do?
- determine etiology of a disease
- identify other important factors concerning the spread of disease
- develop methods for controlling a disease
- assemble data and graphs to outline incidence of disease
What did John Snow do? What year?
1848-1849
- mapped the occurrence of cholera in London
- descriptive epidemiology
What did Ignaz Semmelweis do? What year?
1846-1848
- showed that handwashing decreased the incidence of puerperal sepsis
- experimental epidemiology
What did Florence Nightingale do? What year?
1858
- showed that improved sanitation decreased the incidence of epidemic typhus
- analytical epidemiology
What is the CDC responsible for?
- collecting and analyzing epidemiological information in the US
- publishes morbidity and mortality weekly report
What is morbidity?
incidence of a specific notifiable disease
What is mortality?
deaths from notifiable diseases
What are notifiable infectious diseases?
diseases in which physicians are required to report occurrence
What is morbidity rate?
number of people affected in relation to the total population in a given time period
What is mortality rate?
number of deaths from a disease in relation to the population in a given time
What are blood cultures grown on?
mannitol-salt agar
- coagulase-positive
- gram-positive cocci
