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81 Cards in this Set
- Front
- Back
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Are many infectious diseases preventable?
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yes; vaccinations
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What is a major cause of disability and death worldwide?
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infectious disease
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In a developed country, how many of the deaths are from infectious disease?
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1/10 of the deaths
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In a developed country, infectious disease accounts for how much of poverty, poor nutrition, lack of access to healthcare, lack of clean water, lack of sanitary sewers, overcrowding?
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6/10
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90% of deaths due to Infectious Disease worldwide are caused by just a few diseases. (T/F)
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True
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What is Infection?
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invasion or colonization of he body by a pathogen
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What is a disease?
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any change from a state of health
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What is an acute disease?
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it develops rapidly and lasts a short amount of time; common cold
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What is a chronic disease?
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it develops slowly and it is continual or recurrent; Hep C
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What is a latent disease?
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means a pathogen can remain inactive for longs periods of time; Herpes
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What is a communicable disease?
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any disease that spreads from one host to another host either directly or indirectly; Flu
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What is a contagious disease?
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a disease that is easily spread from host to host; Varicella-Zoster- chicken pox
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What is a non-communicable disease?
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a disease that can't be spread from host to host; Heart disease
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What is epidemiology?
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the study of where and when the disease occurs
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What is incidence?
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the number of new cases of a disease in a given area or population during a given period of time
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What is prevalence?
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the total number of cases of a disease in a given area/ population during a given time period; Existing + New = Total
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What is an Endemic Disease?
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it occurs at a relatively stable frequency in a given population
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What is a Pandemic Disease?
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an epidemic that occurs simultaneously on more than 1 continent
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What is a Sporadic Disease?
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only a few cases occur
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What is Etiology?
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the cause; microbe is the cause
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What do you use to determine the etiology?
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Koch's postulates
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Name all 4 steps in Koch's Postulates.
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1) suspected pathogen must be present in every case of the disease
2) pathogen must be isolated and grown in a pure culture 3) pure culture must cause the identical disease when it is inoculated into a healthy host 4) reisolate pathogen from experimental host and compare it to pure culture= must be identical |
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What is a sign?
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an objective manifestation of disease; it can be observed and measured by others
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What are examples of a sign?
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fever, rash, vomit, swelling
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What is a symptom?
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a subjective manifestation of disease; only felt by patient
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What are examples of a symptom?
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dizzy, fatigue, nausea, headache
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What is pathogenicity?
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the ability of a microbe to cause disease
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What is virulence?
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the degree of pathogenicity
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What are the 3 Virulence Factors?
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1) Extracellular Enzymes
2) Toxins 3) Anti-phagocytic Factors |
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What do Viruluence factors do?
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they increase the virulence of a pathogen
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What is the Virulence Factor Extracellular Enzymes produced by?
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they are produced by some bacteria; excreted by bacteria into environment
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What are examples of extracellular enzymes?
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coagulase (clot formation), kinases (clot busters), hyaluronidase (invade into deeper tissue), leukocidin (decrease phagocytosis)
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What is the virulence factor toxins?
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they are chemicals produced by some bacteria that harm tissues or trigger host immune responses that actually damages the host
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What is a toxiod vaccine?
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a disabled toxin; tetanus shot
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What is an exotoxin?
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it is produced and excreted by bacteria into the environment; gene to produce the toxin would be on a plasmid
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What are the different exotoxins?
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1) cytotoxin
2) neurotoxin 3) enterotoxin |
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What is a cytotoxin?
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An exotoxin; kills hosts cells, affects host cell function (Diphtheria cytotoxin decreases protein synthesis in human cells)
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What is a neurotoxin?
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an exotoxin; interferes with nerve function (tetanus toxin, botulism toxin >paralysis)
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What is a enterotoxin?
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an exotoxin; kills the lining of the GI tract
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Which bacteria produce exotoxins?
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some Gram (+) and some Gram (-) bacteria
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What are endotoxins?
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the LPS in the Gram (-) outer membrane
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What does LPS cause?
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fever, triggers inflammation, hemorrage, clot, shock, and death
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What is the virulence factor anti-phagocytic factors?
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factors that decrease phagocytosis; glycocalyx, slime layer, capsule all decrease phagocytosis
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Can capsules prevent the fusion with lysosomes even if they are phagocytized?
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yes
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What are the 3 different relationships that microbes have with the host?
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1)Mutualism
2)Commensalism 3)Parasitism |
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What is Mutualism?
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the host and the microbe benefit; like the microbes in the GI tract and reproducitve tract
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What is Commensalism?
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one organism benefits/ the other is not harmed or benefits (neutral); like S. aureus or S. epidermidis on skin
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What is Parasitism?
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the microbe benefits/ host is harmed; like Giardia lamblia
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What are reservoirs of infectious disease?
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sites where pathogens are maintained as a source of infection
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What are the 3 reservoirs of infectious disease?
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1)Animal Reservoir
2)Human Carriers 3)Non-living Reservoirs |
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What is an Animal Reservoir?
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its a pathogen in an animal, in tissue of an animal, or in waste of an animal
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What is a zoonotic disease?
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disease in animals and humans
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What is a human carrier?
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the human has no signs or symptoms, but have the pathogen and transmit it
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What is a non-living reservoir?
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-water (vibrio cholera)
-soil (tetanus) -food (Salmonella) |
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What is a portal of entry?
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how the pathogen enters the human
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What are the 4 portals of entry?
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1)Skin
2)Mucous Membranes 3)Placenta 4)Parental Route |
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How is skin a portal of entry?
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unbroken skin is an excellent barrier against pathogens; broken skin= portal of entry
-MRSA |
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Where are the mucous membranes located in your body?
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line all body cavities open to exterior such as the GI tract, urinary tract, respiratory tract, reproductive tract, and conjunctiva(eye)
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What is the most frequently used portal of entry?
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the respiratory tract
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What percentage of pathogens in pregnancies take the placenta as the portal of entry?
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2% of preganancies
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What is the parental route?
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the means by which a portal of entry is circumvented; pathogen is directly deposited into the tissue via bite, needle, nail
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Most pathogens choose a different portal of exit than the one they entered. (T/F)
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False; most use the same portal they entered
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Pathogens never leave in secretions. (T/F)
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False; urine, feces, saliva, semen, breast milk, respiratory droplets
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What is biofilm?
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web of bacteria and polysaccharides; dental plaque, catheters, heart valves, and prostheses
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What helps a pathogen hang on when it is inside its host?
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glycocalyx, slime layer, capsule, fimbrae
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What are the stages of infectious disease? (the graph)
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1)incubation period
2)prodromal period 3)illness 4)decline 5)convalescence |
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What are the 3 modes of transmission?
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1)contact transmission
2)vehicle transmission 3)Vector transmission |
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What are the types of contact transmission?
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-direct contact transmission (person to person body contact between hosts)
-indirect contact transmission (person to person via fomite) -droplet transmission (respiratory droplets) |
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What is vehicle transmission?
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when a pathogen is spread via a vehicle: water, air, food, body fluids
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What are the different types of vehicle transmission?
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-airborne transmission (respiratory droplets, travel more than 3 ft.)
-waterborne transmission (drinking contaminated water; usually fecal-oral) -foodborne transmission (poorly cooked food) -body fluid transmission (blood, urine, saliva, semen, vaginal secretions) |
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What are the different types of vector transmissions?
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-biological vector (vector or animal serves as a host for multiplication of a pathogen)
-mechanical vector (passively carry the pathogen to a new host, roach, flies) |
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What are nosocomical infections?
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infection acquired from a healthcare facility
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What % of patients who get catheters get a nosocomical UTI?
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10%
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What are common sites of Nosocomical Infections?
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32%> urinary (UTI)
22%> at surgical site 15%> in lungs 14%> bloodstream (systemic) |
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What are common Nosocomical Infection organisms?
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-staph aureus
-E. coli -pseudemonas aeruginosa -clostridium difficile |
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Handwashing decreases transmission of nosocomical infections by what %?
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50%!
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What is the transmission rate for a single needlestick with Hep B virus?
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6-30%; there is a vaccine for this> immunoglobulins= 90% effective
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How effective is the immunoglobulins treatment in Hep B?
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90%
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What is the transmission rate of a single needlestick with Hep C?
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1.8%; no vaccine, use interferon treatment
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What is the transmission rate of a single needlestick with HIV?
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0.3%; no vaccine, HAART therapy
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What treatment is used for HIV virus?
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HAART therapy
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