Transmission Flashcards
(31 cards)
Streptococcus pneumonia (pneumococcus)
children=primary vector direct spread=middle ear, sinuses, trachea, bronchi, lungs Hematogenous spread= pleural cavity, CNS, bones, joints, peritoneal cavity, heart valves
Direct spread via close contact
(i.e. in crowded living conditions!)
Acinetobacter baumannii
.UTI: urination from fomite source;
enters through catheters
soil, foods (vegetables, meat, fish)
skin colonization (rarely throat,
nares, GI tract);
contaminated environmental sites
and medical equipment; health-
care personnel w/ skin colonization
Bordetella pertussis
Very contagious
Most don’t seek treatment and
become important reservoir of
disease
spread from person-->person by coughing, sneezing, etc. infants infected by caregivers/ siblings (reservoirs) .
Francisella tularensis
direct contact w/ Rabbits, rodents, arthopods tick bites, deer flies contaminated H20, blood, tissue while handling carcasses of infected animals eating badly cooked meat of infected animals inhalation of dust from bad soil,etc.
Doesn’t pass from person–>person
.
Yersina pestis
Animal reservoir (ground rodents, cats, rabbits
transmitted via vector (flea)
pneumonic form transmitted human-
to-human
(Bubonic plague via flea from ground
rodents and rabbits)
Primary pneumonic: from human or cat w/
pneumonic plague; act of bioterrorism
.
Brucella spp.
Animal reservoirs (cows, sheeps/goats, pigs)
(bison, elk, wild boars, herbivores)
Genitourinary tract&mammary glands infected
Direct contact w/ animals or
consumption of unpasterurized
dairy products
Rarely inhalation of aerosols from animal
CAN’T be transmitted human-to-human
or by arthropod vectors
.
Coxiella burnetii
Animal reservoirs Inhalation of animal aerosols handling viscera (including amniotic fluid, placentas) drinking raw milk sometimes by ticks (*has spore-like form that permits distribution over several miles by wind…Category B agent of bioterrorism)
CAN’T be transmitted human-to-human
.
Chlamydia
Psittacosis: reservoir=birds
spread by inhaling organisms in dried bird feces
Pneumonia: reservoir=humans
respiratory spread
Ocular, respiratory, genital tract infections:
reservoir=humans;
Neonatal infections: contracted from mother
during pasage through birth canal
Most common sexually transmitted disease
Often clinically silent, so left untreated, which
contributes to sexual transmission
Severe Pneumonia: concentrated aerosols
(C. trachomatis)
.
Legionella
attacks 2-5% of those exposed
(Pontiac fever attacks 95% of those exposed
indiscrminately)
Found in environment, esp. H2O (best in warm water) People breathe in mist/vapor Think: hot tubs and air conditioning systems on tall buildings
Bacteria NOT spread human-to-human
.
Mycoplasma
.
Mycobacterium bovis
humans and cows = reservoirs consumption of unpasteurized milk (can lead to extrapulmonary TB-->bone infections-->hunched backs) .
Mycobacterium avium
.
Mycobacterium leprae
.
Mycobacterium tuberculosis
humans= only reservoir
People who have TB infection but not TB
disease are NOT infectious (and will normally
have normal CXR)
SNEEZING, coughing, talking, etc.
.
Nocardia Asteroides Complex
inhalation
(not transmitted from person to person,
not usually nosocomial)
contamination of wounds w/ soil (cutaneous
disease)
.
Actinomyces israelii Complex
.
Histoplasmosis
Histoplasma capsulatum
.Inhalation of airborne conidia
no person-to-person transmission
Blastomycosis
Blastomyces dermatitidis
.
Coccidioidomycosis
Coccidioides immitis
.Release of endospores from spherule
Extremely infectious
proper precautions in lab need to be taken
Aspergillosis
.inhalation of conidia
hospital air ducts
Mucormycosis
(Zygomycetes fungi:
Absidia, Rhizopus, Mucor Species)
.
Pneumocystosis
Pneumocystic jerovici (carinii)
.
Influenza viruses
.pigs= intermediate host b/c birds
cannot directly infect humans
High concentration of virus in respiratory
secretions during initial phase of illness, so may
be passed on before you know you are sick
person-to-person via airborne droplets from
coughing, sneezing, talking
direct contact w/ contaminated surfaces/object
Rhinoviruses
Only 70-80% of those exposed have symptoms
Not related to temperatures, fatigue, sleep
deprivation
virus spread in large amounts; can occur few
days before symptoms, peaks days 2-7 of illness
may last as long as 3-4 wks
occurs after close exposure to infected
respiratory secretions & by large/small particle
aerosolization
Infection by transfer from fomites (environ.
objects, i.e. door knob) is common
hand-to-hand contact; self-inoculation of eyes/
nose; aeorsol particles–>ciliated areas of nose/
nonciliated areas of nasopharynx through
receptors in posterior nasopharynx
.
