14: Principles of Disease and Epidemiology Flashcards
disease causing, have their own mechanism for invading our tissues
pathogenic microorganisms
single most important virulence factor for microorganisms
capsule
what purpose does glycocalyx in the capsule serve?
prevents phagocytosis
science that deals with the study of disease and its causes
pathology
cause of a disease, pathology’s first concern
etiology
the manner and process by which a disease develops
pathogenesis
the invasion or colonization of the body by potentially pathogenic microbes. does NOT necessarily indicate disease
infection
obvious symptoms of infection
clinical infection
no or few symptoms of the infection
subclinical infection
any change from a state of health. an abnormal state in which part or all of the body is not properly adjusted or is not capable of carrying out its normal function
disease
any change from a state of health caused by pathogens
infectious disease
what is the best source for a baby’s normal flora?
the mother
is the placenta sterile?
no, resident microbes in both placenta and amniotic fluid
from the maternal vagina, becomes the predominant organisms in the newborns intestine (general)
lactobacilli
example of microbe from maternal vagina in newborns intestine
lactobacillus acidophilus
example of microbe from foods in newborns intestine
Escherichia coli
organisms that establish a more or less permanent residence in or on the body without normally causing disease
normal flora, normal microbiota
microbial communities that live in and on the human body
microbiomes
project to analyze microbiomes
Human Microbiome Project
what two things do they think may damage the intestinal microbiome, resulting in later disorders in humans?
antibiotics and food preservatives
organisms which are present for hours, days, weeks,and then disappear
transient microbiota
frequently causes transient bacteremias
alpha hemolytic streptococci, viridians streptococci
body sites which are currently believed to be bacteriologically sterile. if normal flora bacteria obtain access to these areas, disease will often result
blood, brain, spinal fluid, endometrium
one of the normal bacterias found in the vagina that may gain access to and infect the uterus (endometrium) during criminal abortion
clostridium perfringens
process where normal flora can benefit the host by preventing the overgrowth of harmful microbes
microbial antagonism or competitive exclusion
example of microbial antagonism where lactobacilli cause and acidic pH in adult female vagina. upset can lead to what?
candida albicans vaginitis
example of microbial antagonism where E. coli is found in the intestine and produces _____ proteins that inhibit the growth of other bacteria of the same or closely related species, such as pathogenic _____ and _____
bacteriocins, salmonella, shigella
What does lactobacillus acidophilus use for its terminal electron acceptor?
pyruvic acid (3C molecule)
example of microbial antagonism where normal microbiota of the intestine effectively inhibits _____
clostridium difficile
when the normal flora is eliminated by antibiotics, clostridium difficile flourishes, produces toxin, and can cause potentially ______
fatal colitis (inflammation of the colon)
some recent cases of colitis caused by clostridium difficile have been successfully treated by giving the patient what?
capsules containing a spouse’s normal fecal flora
term used to describe the living together of the host and its normal flora
symbiosis
type of symbiotic relationship where one of the organisms is benefited and the other is unaffected. some of the bacteria that live on our sk
commensalisms
type of symbiotic relationship where both organisms benefit
mutualism
normal flora escherichia coli that live in our intestine that benefit from nutrients in the colon while they simultaneously make vitamin K (used in blood clotting factors) and B vitamins that are used by our body’s cells. this is an example of what type of relationship?
mutualism
type of symbiotic relationship where one organism benefits at the expense of, or detriment to, the other. many disease-causing bacteria fall into this category
parasitism
intentional application or ingestion of helpful live microbial cultures to a host to exert a beneficial effect is gaining popularity
probiotics
live culture yogurt (which contains ______) is ingested because it is known that certain _____ can alleviate diarrhea or prevent vaginal yeast infections
lactobacillus acidophilus, LAB (lactic acid bacteria)
what is the commercial probiotic used with baby chickens?
preempt
generally harmless bacteria, such as normal flora eschericia coli in the intestine, can become a serious pathogen when it gains access to other regions of the body
opportunistic pathogens
opportunistic pathogenic fungus which can cause deadly pneumonia in persons with AIDS
pneumocystis jirovecii
opportunistic pathogen often found in the upper respiratory tract, bu which can cause deadly meningitis if it escapes into the blood stream
neisseria meningitidis
opportunistic pathogen, a normal resident of the nose and throat, which can cause pneumonia when aspirated
streptococcus pneumoniae
“the old man’s friend” kills a lot of old people with aspiration pneumonia
streptococcus pneumoniae
example of microbe cooperation: pathogens that cause periodontal disease and gingivitis have been found to have receptors, not for the teeth, but for the ________ that colonize the teeth.
oral streptococci
pioneered the search for infectious agents with this technique
Robert Koch, Koch’s postulates
Koch’s postulates can be modified if an organism will not grow on _____
artificial media
- same pathogen must be present in every case of the disease
- pathogen must be isolated from the lesions and grown in pure culture.
- pathogen from the pure culture must cause the same disease in experimental animals
- pathogen must be reisolated from the diseased animal
Koch’s Postulates
changes in body function, such as pain and malaise. subjective changes are not apparent to an observer
symptoms
vague feeling of body discomfort
malaise
objective changes in body function that a physician can observe and measure (lesions, swelling, fever, paralysis, etc)
signs
changes produced in tissues by disease
lesions
specific group of symptoms or signs that may accompany a particular disease
syndrome
diseases that can be spread from one host to another, either directly or indirectly
communicable diseases
communicable diseases that are easily spread form one person to another
contagious diseases
example of contagious diseases
chickenpox and measles
disease that are not spread form one host to another, but are caused by environmental microbes or by the host’s own normal flora
noncommunicable diseases
example of noncommunicable disease is tetanus, which is caused by _______ found in the soil, and _____, caused by a woman’s own normal flora
clostridium tetani, yeast vaginitis
a disease that occurs occasionally, example?
sporadic disease, typhoid fever
a disease that is constantly present in a certain population, example?
endemic disease, common cold
a disease that man people in a given area acquire in a short period of time, example?
epidemic, salmonella from contaminated peanut butter
an epidemic disease that occurs worldwide, example?
pandemic disease, influenza and AIDS
this disease may reach epidemic status at a university
neisseria gonorrhoeae
disease that develops rapidly, but only lasts a short time, example
acute disease, influenza
disease that develops more slowly and less severely, but may continue or recur for long periods, example
chronic disease, tuberculosis
disease progression between acute and chronic, example
subacute disease, SBE and septic emboli
SBE
subacute bacterial endocarditis
____ is caused by normal flora of the mouth (_______) which travels in the body and colonizes onto defective semilunar heart valve, causing ________ to form. Bacteria and diseased tissue then break off (_______) causing continuous bacteremia and spread of infection. Death may take many weeks. It is prevented by _____.
SBE, alpha-hemolytic streptococcus pyrogenes, cardiac vegetation, septic emboli, antibiotics
disease in which the causative agent remains inactive for a time, but then become active to produce symptoms of disease, example
latent disease, shingles is the reactivation of varicella virus
rate at which a disease or an epidemic spreads and the number of individuals involved are determined in part by the _______
immunity of the population
can provide long-lasting and sometimes lifelong protection of an individual against certain diseases
vaccination
people who are immune to an infectious disease will not be ____, thereby reducing the occurrence of the disease
carriers
when many immune people are present in a community, this may exist
herd immunity
abscess is what type of infection
local infection
measles is what type of infection
systemic (generalized) infection
highly contagious systemic infection transmitted by inhalation
measles
what type of infection would an oral bacteria that can spread from the teeth to cause a local infection on a heart valve.
focal infection
cardiac vegetation of heart valves caused by SBE is an example of what type of infection
focal infection
toxic inflammatory condition arising from the spread of microbes, especially bacteria and their toxins, from a focus of infection
sepsis
systemic infection arising from the multiplication of pathogens in the blood.
septicemia, blood poisoning
common cause of sepsis
septicemia
simply the presence of bacteria in the blood, which may or may not be associated with disease
bacteremia
refers to the presence of toxins in the blood, example
toxemia, tetanus toxin
refers to the presence of viruses in the blood
viremia
an acute infection that causes an initial illness, such as influenza
primary infection
infection caused by an opportunistic pathogen after the primary infection has weakened the body’s defenses, example
secondary infection, hemophilus influenzae
infection that does not cause noticeable illness, which can be carried by some persons who never develop the illness, example
subclinical (inapparent) infection, poliovirus, hepatitis A virus, Typhoid Mary
make the body more susceptible to a disease and influence the course of the disease
predisposing factors
example of disease with genetics as predisposing factor
San Joaquin Valley Fever caused by Coccidioides immitis, also called Lower Sonoran Life Zone, develops progressive systemic disease in people with darker colored skin
example of disease with sex and hormones as predisposing factor
yeast vaginitis from candida albicans
example of disease with lifestyle as predisposing factor
alcoholics rose gardener’s syndrome caused by dimorphic fungus (subcutaneous mycoses) sporothrix schenckii and treated with potassium iodide
example of disease with lack of good judgment being a predisposing factor
clostridium perfringens causes gas gangrene and clostridium tetani causes tetanus in traumatic wounds
example of disease with chemotherapy as a predisposing factor
leukopenia
decrease in number of leukocytes, increased risk of infection
leukopenia
example of disease with age as a predisposing factor
streptococcus pneumoniae “old mans friend” aspiration pneumonia
time interval between actual infection and the first appearance of any signs or symptoms of disease
period of incubation
period where the first vague symptoms of disease appear
prodromal period
period where disease is most severe. stage where death occurs
period of illness
time when the signs and symptoms of disease subside, during this time, the patient is vulnerable to secondary infections
period of decline
period when person regains strength and the body returns to normal
period of convalexcence
during what stage of disease is a person considered contagious
all of them
continual source of the pathogen with adequate conditions for multiplication and an opportunity for transmission
reservoirs of infection
people who transmit the disease but who have no obvious signs of the disease, example
carriers, nasal carriage of staphylococcus aureus
diseases transmitted from animals to humans
zoonoses
nonliving reservoirs
soil, water, food
soil which contains pathogenic microbes, example
nonliving reservoir, coccidioides immitis (San Jauquin Valley Fever)
water contaminated by pathogens, example
nonliving reservoir, vibrio cholerae
food improperly prepared or stored, example
nonliving reservoir, trichinella spiralis
types of contact transmission
direct contact (person-person), indirect transmission, adroplet infection
disease transmission by means of a nonliving object
indirect transmission, fomite
infectious droplets travel a very short distance
droplet infection
transmission of disease agents by a medium, such as water, food, or air
vehicle transmission
spread of agents that travel more than one meter from the reservoir to the host
vehicle transmission
example of airborne transmission
coccidioidomycosis in lower sonoran life zone, rubeola virus which causes measles
animals that carry pathogens from one host to another
vectors
passive transport of the pathogen on the insect’s feet or other body parts, example
mechanical transmission, salmonella or shigella from feces of infected people to food on table
active process when the pathogens reproduce in the vector, example
biological transmission, plasmodium in the gut of an anopheles mosquito
hospital acquired or health-care associated infections
nosocomial infection
infection or disease that is a direct result of a health care workers actions
iatrogenic disease
nosocomial infections result from the interaction of what three factors
microorganisms in the hospital, compromised host, and chain of transmission
4 common hospital pathogens
escherichia coli, staphylococcus, pseudomonas aeruginosa, candida albicans
burn patients are at high risk for nosocomial infection with what pathogen that is green in color and smells like rotten fruit
pseudomonas aeruginosa
hospital microbes share _____ so multiple resistance to antibiotics develops
R factors
common nosocomial infection responsible for yeast vaginitis, thrush, and meningitis
candida albicans
suppressed immune system when drugs or disease interfere with the activity of _____ or _____
B-lymphocytes or T-lymphocytes
another term for leukopenia
leukocytopenia
examples of impaired cellular activity within the body that can allow disease to occur
dabetes, cirrhosis of liver, malnutrition, poisonings, etc
what accounts for 13% of all nosocomial diseases
UTIs with escherichia coli
what is the principal route of transmission of nosocomial infections
direct contact transmission from hospital staff to patient
what fomites might be responsible for indirect transmission of nosocomial infection
stethoscopes, neckties
accredited hospitals must have. monitors incidence and distribution of infections, conducts education, investigates outbreaks of disease, etc
infection control nurse
what organizations monitor emerging infectious diseases
CDC and WHO
science that deals with when and where diseases occur and how they are transmitted
epidemiology
