blood infections

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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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


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.


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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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

blood infections

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