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Flashcards in Transmission Deck (31)
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1

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!)

2

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

3

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)
.

4

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
.

5

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
.

6

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
.

7

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
.

8

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)
.

9

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
.

10

Mycoplasma

.

11

Mycobacterium bovis

humans and cows = reservoirs
consumption of unpasteurized milk
(can lead to extrapulmonary TB-->bone
infections-->hunched backs)
.

12

Mycobacterium avium

.

13

Mycobacterium leprae

.

14

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.
.

15

Nocardia Asteroides Complex

inhalation
(not transmitted from person to person,
not usually nosocomial)

contamination of wounds w/ soil (cutaneous
disease)
.

16

Actinomyces israelii Complex

.

17

Histoplasmosis
(Histoplasma capsulatum)

.Inhalation of airborne conidia
no person-to-person transmission

18

Blastomycosis
(Blastomyces dermatitidis)

.

19

Coccidioidomycosis
(Coccidioides immitis)

.Release of endospores from spherule

Extremely infectious
(proper precautions in lab need to be taken)

20

Aspergillosis

.inhalation of conidia
hospital air ducts

21

Mucormycosis
(Zygomycetes fungi:
Absidia, Rhizopus, Mucor Species)

.

22

Pneumocystosis
(Pneumocystic jerovici (carinii))

.

23

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

24

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
.

25

Adenovirus

Viruses can be shed for months from lymphoid
tissues (tonsils, adenoids, Peyer's patches)

inhalation of water droplets by fecal-oral route
(i.e. waterborne transmission/direct inoculation)

inadequately chlorinated swimming pools
.

26

Coronaviruses

Wide range of host species

person-to-person via airborne droplets (cough,
speaking, sneezing)

direct contact w/ contaminated surfaces/object

SARS reservoir=bats

fecal transmission
.

27

Respiratory Syncytial Virus (RSV)

Direct person-person contact/ large droplet
spread (i.e. sneezing)
.

28

Human Metapneumovirus (hMPV)

Direct person-person contact/ large droplet
spread (i.e. sneezing)
.

29

Human Parainfluenza viruses 1-4 (hPIVs)

Direct person-person contact/ large droplet
spread (i.e. sneezing)
.

30

Hantavirus Pulmonary Syndrome (HPS)

rodent hosts (usually not pets though)
(each virus is adapted to single host rodent
species)


breathing air containing aerosolized rodent
saliva, urine, or feces

Rodent bite (rare)
touch something contaminated then touch nose
or mouth
food contaminated w/ rodent urine, feces, etc.

No person-to-person cases reported
.

31

Fungal Infections in General

.