chaper 14 Flashcards
active growth of pathogens
infection
Presence of microbes/pathogens
contamination
infection acquired in health facilities/setting
nosocomial infection
disturbance in state of health of the host
disease
disease caused by microorganisms
infectious disease
disease-causing microbes—-> non-pathogen= non-disease causing
pathogen
degree of pathogenicity
virulence
ability to cause disease
pathogenicity
D= NV/R what does each letter stand for?
D= disease N= # of pathogens V= virulence R= resistance *** larger number in numerator = higher chance of getting disease
disease is often a result of ____________
infection
what is normal flora
microbes that live on and in the body without causing apparent harm
healthy people should have equal _____________&______________
- suseptability
- resistance
- higher susceptibility , lower resistance = good health
- lower susceptibility, higher resistance = disease
what are the two types of normal flora?
- permanent
- transient
some parts of the body that have normal flora??
upper digestive tract (sterile)
eyes and skin
reproductive tract
what are the 3 types of symbiotic relationships?
- mutualism
- commensalism
- parasitism
both benifit, ex: bacteria in human colon
mutualism
1 is benefitted and other is not harmed
commensalism
pathogen causes disease, human harmed flora benifitted.
parasitism
describe how a newly born baby acquires his normal flora
placenta in healthy mothers= sterile
* as the baby goes out of the birth canal the baby acquires NV when it crys, eats, touched by parents, doctors, other materials such as clothes.
what are some pathogens that can cross the placenta?
protozoan
bacteria(syphilis)
DNA viruses(asymptomatic)
RNA viruses(aids)
what is the importance of normal flora?
- prevent attachment of invaders
- deplete essential nutrients
- produce antimicrobial substances that can kill other bacteria
in which cases can normal flora cause disease?
- immune suppression
- changes in normal flora
- introduction of NV into an unusual site of the body
- E. coli can cause UTI bc its norm. habitat is large intestine
what are the steps from beginning to end on how pathogens cause disease…
- transmission(portal entry) 2. adherence to target tissue
- invasion 4. colonization 5. damage of host
- exit(portal of exit)
what is meant by portal of entry?
- cuts, direct contact, food
* thru the respiratory tract—>lungs—->blood(which carries disease thru out the body)
what are the portal of entry of pathogens in the human body?
anus, broken skin, insect bite, ear, eye, nose, mouth, placenta, vagina, penis, and urethra
- placenta route-deep wounds/surgery= not normal transmission
what are used by pathogens to adhere to target tissues? examples
1.attachment of pathogens to cells
2.uses adhesion factors
-attachment proteins
adhesions
ligands
-specialized
once the pathogens are in their target tissues and if the growth requirements are met, the pathogens_______________
invade the tissues and grow
what are examples of virulence factors?
enzymes, toxins, anti phagocytic factors, anti phagocytic chemicals
enzyme that degrades hyaluronic acids= pathogens can enter.
hyaluronidase
enzymes breaks down collagen and pathogen invades deeper tissues
collagenase
enzymes that are produced by pathogenic bacteria, form a clot which protects bacteria in a clot.
coagulase
enzyme that breaks down the clot, and releases the bacteria into pathways
streptokinase
antiphagocytic factor examples
bacterial capsule
antiphagocytic chemicals…
produce chemicals
ex: leukocidins= prevent fusion of lysosome and phagocytic vesicles (kill white blood cells)
what is the portal of exit in the human body
ear wax, blood, skin, anus, tears, nose secretions, saliva, vaginal secretions (blood)
what is reservoir of infection
sites where pathogens are maintained as a source
what is zoonosis
animal to man diseases
what are the 3 modes of disease transmission
- contact
- vehicle
- vector
examples of contact transmission
direct- hands, kissing
indirect- drinking glass
droplet- sneezing within 1 meter
examples of vehicle transmission
airborne- dust
waterborne- steam, swimming pool
foodborne- poultry, seafood
examples of vector transmission
mechanical- body of flies, roaches
biological- lice, mites, mosquitoes(pathogens have to grow in a vector)
how are diseases manifested?
symptomrs- pain, nausea, headache, chills
signs- both people can see, ex: swelling, fever, rbc count
syndrome- group of signs and symptoms, Ex: only you can feel it
5 signs of infections disease
- incubation period- no signs/symptoms
- prodromal peridod- vague gen. symtoms
- illness- most severe signs and symptoms
- decline- declining signs/sym
- convalescence- no signs/sym
how are infectious diseases classified
- taxonomic groups of pathogens, Ex: fungal or viral diseases
- body system affected by pathogens, Ex: nervous system(skin), cardiovascular system, and respiratory system
- how disease is spread
- occurrance
- longevity and duration of the disease
how disease is spread…
- communicable: spread directly or indirectly
contagious: easily spread Ex: common cold - Non communicable: not spread Ex: acne
types of occurrence
A. prevalence: # old plus new cases/time of disease (higher bc includes old cases)
incidence: # new cases/given time of disease
B. frequency and geographic distribution
-Sporadic: occurs occasionally
-Endemic: always prsent
-Epidemic: many people affected within short period
-Pandemic: worldwide epidemic
types of longevity and duration of the diseas..
acute- develops rapidly, last short time
chronic- develops slowly but continual and recurrent
sub-acute- btween acute and chronic
latent- pathogens remain inactive for long period before producing signs/sym
what is etiology?
study of location, course, and transmission of diseases within population
what is epidemiology
study of the cause of disease
