blood infections
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8/2/2019 Blood Infections
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Transmission Pathogenesis Incidence Symptoms Other Diseases Vaccine?
Infectious Endocarditis
Bacteria or virus in the
blood infects interior
heart muscle, causing
damage and resulting
clot
Bacteria stick to the clot,
may increase it
Emboli clot breaks off,
flows to a smaller blood
vessels and blocks blood
flow petechial
hemorrhages, stroke,
coronary embolism
Abs bind the emboli and
recruit complement,
increasing cell damage
Common causes: oral-
streptococci enter via
bleeding gums
Skin or fecal bacteria
enter via wounds
Bacteremia
Same as endocarditis
bugs and
Group B Strep (GBS)
Beta hemolytic
streptococcus
S.agalactiae normal
vaginal flora, but not
present in all women.
Testing in last 3 weeks
before giving birth
Most common cause of
neonatal death in US
Puerperal fever, sepsis
in mother, post birth.
Major cause of death
due to childbirth if no
access to clean water,
Abx.
Neonatal bacteremia,
meningitis, pneumonia
depending on where
infant infected
Epstein Barr Virus (EBV;
herpes 4)
Droplet-hard to get:
requires high ID50
Kills pharyngeal cells,
causing inflammation.
Causes some B cells to
divide, encouraging viral
replication. Makes B
cells look like
Monocytes (atypical
lymphocytes_
Tissue tropism: lytic in
pharyngeal epithelia,
latent in B cells
-Asymptomatic in most
healthy people, just feel
tired
-fetuses if mothers
primary infection is in
pregnancy, fetus may be
born jaundiced
-hearing loss and
learning disabilities may
develop later.
Immunocompromised
pneumonia if
respiratory, flu like
symptoms and
pneumonia if via
transfusion/transplant
Lyme Disease
Borellia borgdorferi:
fastidious spiral
bacterium with reservoir
in mice, problem
especially in E. US
Deer tick Difficult to study!
Hypothesis: unusual cell
wall LPS triggers
confused chronic
immune reaction
wherever pathogen is
(first skin, later
joints/brain)
-Rash sometimes
bullseye shape with
fever, pain for months.
Lack of neutrophil
response, chronic
inflammation.
-Arthritis later
inflammation to joints,very painful
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8/2/2019 Blood Infections
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Transmission Pathogenesis Incidence Symptoms Other Diseases Vaccine?
Chagas Disease
Trypanosoma cruzi
Protozoan flagellate
Vector, vertical kissing
bug so called because it
is attracted to CO2
exhaled while victim
sleeps. Bites near
mouth, but actual
transmission is from its
poop, which may enter
through eye or wound.
Lives in thatched roofs
May stay at bite site
inflammation. If
disseminates, forms a
pseudocyst inside
cardiac or autonomic
nervous system cells
Distribution: Latin-
AmericaUS issue with
immigrants, blood banks
Acute: flu-like
symptoms. If poop was
in eye, get droopy eye
for a few weeks, like the
kid. Some develop
chronic infection and
may immediately or
years later suffer organ
failure, especially of
heart or GI, due topseudocyts
Brucellosis
Brucella spp.
Food esp. unpasteurized
milk.
Goats/sheep, swine,
cattle
Flu-like symptoms. May
develop into chronic
nocturnal fever
-Causes spontaneous
abortion in humans too
Bioterrorism: has been
explored as possible
bioterror agent
Tularemia (Rabbit
fever)
Francisella tularensis
fastidious bacterium
Multiple usually would
infected while
butchering small
mammals.
Ex: rabbits, squirrels for
meat. Improbable but ID
50 is low!
Ulcerated would
Granulomas in skin
Buboes
-if disseminated, high
fever, organ failure, high
mortality
Bioterror: can also be
inhaled, so proposed
bioterror agent (but so
tough to grow this is
really unlikely)
Plague Black plague
name for buboes
Yersinia pestis
Gram negative bacteria
Vector: flea bite Lives in macrophages,
spreads to lymph nodes
and rapidly multiplies.
-Massive immune
recruitment there, and
dying bacteria release
LPS into lymph, then
blood septic/toxic
shock
Bubonic Plague: buboes
are purple, swollen
lymph nodes. High
fever, death in days
Rickettsial infections
Obligate intracellular
bacteria. Very small and
simple, kind of likeviruses, and also
intracellular.
Arthropods. All are
transmitted by
insect/arachnid bites
Rickettsial infections
Rocky Mountain
Spotted Fever
R. rickettsia
Vector: tick Infects and kills
endothelial cells,
causing blood vessel
collapse.
-rash due to blood
leaking into tissues,
possible clot
development and
subsequent embolism.
Rickettsial infections
Typhus flu-like
symptoms
Epidemic Typhus
R. prowazeckii
Vector: lice
Endemic Typhus
R. typhi
Vector: rat flea
-rash (same rash as
RMSF), very high fever,
high mortality if
untreated
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Transmission Pathogenesis Incidence Symptoms Other Diseases Vaccine?
Arboviruses
Insect born viruses
Aedes mosquitoes-
striped mosquito
invasive to Americas
Distribution Dengue
Fever: tropics (can only
be spread by Aedes)
US Emergence?
Mosquito recently seen
in SW US
Distribution of Yellow
fever: Equatorial Africaand Latin America
West Nile born by other
species of Aedes
mosquito genus, found
father north, including
here. Serious human
infections rare.
Dengue Fever:
Quebrante huesos
breakbone fever.
Terrible muscle and
joint pain, high fever.
Dengue Hemorrhagic
fever: may develop,
depending on strains.
Hemmorhage internal
and external
Yellow fever virus:
diseases similar to
dengue fever but pain is
less and liver problems
more. Jaundice, swollen
abdomen, Hemorrhagic
fever may develop.
Vaccine for Yellow
Fever: most effect
vaccine ever developed.
You get a yellow card
(photo) to prove you
have it.
Ebola and Marburg
viruses
Blood reservoir
unknown; bats
suspected. Possibly
begins with bat bite and
spreads to victims
caretakers
Break down cell: cell
boundaries between
epi/endothelial cells
Outbreaks: small, every
few year in Central/East
Africa. Only large
outbreaks (numbering in
hundreds) associated
with iatrogenictransmission: non sterile
practices in hospital
care
Fever
Sever hemorrhaging
Inside and out
Lymphatic filiariasis
Sometimes called
elephantiasis
Wuchereria bancrofi,
Brugia malayi
roundworms
Mosquito Baby worms in blood;
adult worms live in
lymph vessels. Have
bacteria inside them
that, when released on
worm death, cause
inflammation, scarring.
Distribution: tropics Early: parasitemia (baby
worms in blood), fever,
fatigue. People born in
endemic areas may not
have symptoms. Later, if
untreated: painful
swollen limbs. scrotum
from repeated scarring.
Malaria: review from
unit 1
HIV: review from unit 5
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