Zoonotic Infections

Question 1

Zoonotic Bacteria

animal vs non-animal vector:

Answer 1

Question 2

Bartonella henselae:

causes:

also rare cause of 2 things:

hallmark:

Treatment:

Answer 2

Cat Scratch Fever

Cat scratch (almost always a child) • Red, swollen area 3-10 days later • Regional lymphadenopathy (hallmark of disease) • Tender, red lymph nodes

Bacillary Angiomatosis (vascular lesions) • Diffuse skin papules in AIDS patients • Often mistaken for Kaposi Sarcoma

Endocarditis (rare cause, culture negative)

Treatment: Doxycycline, Azithromycin

Question 3

key differences between Kaposi Sarcoma & Bacillary Angiomatosis (BA)

Answer 3

similar appearances, aids patients, but kaposi caused by HHV 8

Kaposi Sarcoma: Lymphocytes

BA: Neutrophils/lymphocytes

Question 4

8 Granulomatous Infections: including prototype & that which causes Granulomatosis Infantiseptica

Answer 4

Tuberculosis* prototype

Fungal pneumonias (Histo, Blasto, Coccidio)

Bartonella (cat scratch disease)

Brucella

Listeria in infants (Granulomatosis Infantiseptica)

Leprosy

Schistosomiasis (worm)

Syphilis (gummas)

Question 5

Brucella

Lives in:

causes:

Classic patients:

Treatment:

Answer 5

Lives in cows, goats • Infection from unpasteurized milk or animal exposure

Brucellosis (aka undulant fever) • Flu-like illness • High fever that rises and falls • Profuse sweating

Classic patients: • Worker in meat packing plant • Traveler from Mexico who consumed milk/cheese

Treatment: Doxycycline + streptomycin/rifampin

Question 6

Chlamydophila psittaci causes: from: classsic patient/symptoms:

treatment:

Answer 6

Psittacosis • Parrot fever Infection from inhalation dried feces

Classic patient: Pet store employee • Fever, headache, and dry cough

Treatment: Doxycycline

Question 7

Coxiella burnetii causes: from:

unique feature:

classic scenerio b/c:

symptoms:

diagnosis:

treatment:

Answer 7

Q fever

Farm animals: cattle, goats, sheep

Forms spores that get inhaled • High concentrations in placenta of infected animals CLASSIC SCENERIO: farm worker delivering cow babies gets sick • Symptoms • Pneumonia with flu symptoms (fever, headache, myalgias) • Endocarditis

Diagnosis: Serology (antibodies)

Treatment: Doxycycline

Question 8

Coxiella burnetii causes: from:

Bartonella causes: from:

what to know about these two:

Answer 8

Coxiella burnetii • Q fever • Farm animals (cattle, sheep, goats)

Bartonella • Cat scratch fever • Cat fleas

culture negative endocarditis: Evidence of endocarditis with sterile BCx

Question 9

Francisella tularensis

causes:

hallmark sign:

treatment:

Answer 9

Tularemia (Rabbit fever),

Ulceroglandular tularemia (most common form) Fever, chills malaise • Classically the fever abates for few days, returns • Skin ulcer at site of insect bite • Swollen, painful lymph nodes

Important reservoirs: Ticks, deer flies, rabbits

Treatment: Streptomycin (Doxycycline okay, too)

Question 10

Pasteurella think of: because of where it lives:

key infections:

treatment:

Answer 10

Lives in mouth of cats and dogs

Infection: Cat/dog bites or scratches • Key infections: • Cellulitis • Osteomyelitis

Bite wounds usually polymicrobial (S. Aureus)

Broad spectrum empiric therapy

Amoxicillin-clavulanate (oral)

Ampicillin-sulbactam (IV)

Piperacillin-tazobactam (IV)

Question 11

Leptospira interrogans

classic case & treatment:

Answer 11

Lives in rodents → shed in urine • Illness commonly from contaminated water • Classic case is surfer or swimmer in tropics

Treatment: Doxycycline or Azithromycin

Question 12

Ehrlichia

vector/resevoir:

key micriobio detail:

causes: symptoms:

diagnosis:

treatment:

Answer 12

Tick-borne illness (vector: Lone Star tick)

White tail deer are principal reservoir

Obligate intracellular bacteria • “Berry like” inclusions in monocytes (morulae)

Ehrlichiosis Symptoms • Flu-like illness • Leukopenia • Thrombocytopenia

Diagnosis: Giemsa stain, serology

Treatment: Doxycycline

Question 13

Anaplasma similar to:

Answer 13

Anaplasmosis

Bacteria very similar to Ehrlichia • Morula seen in granulocytes (not monocytes)

Tick vector: Ixodes scapularis (not Lone Star tick)

Similar symptoms, treatments to Ehrlichiosis • Fever, joint pains • Low WBCs, platelets

Blood smear: granulocytes (not monocytes) with inclusions

Question 14

Lyme disease treatment:

Answer 14

• Treatment: Doxycycline or Ceftriaxone

Question 15

Rickettsia and Chlamydia are both:

Answer 15

Obligate intracellular bacteria • Use host ATP

Question 16

Three subtypes of Rickettsia

all infections occur from:

Answer 16

R. rickettsii (Rocky Mountain Spotted Fever)

R. typhi (Murine typhus)

R. prowazekii (Epidemic typhus)

• All infections occur from ticks-fleas-lice

Question 17

Rocky Mountain Spotted Fever

caused by:

transmission:

triad of symptoms: including hallmark rash

rare complications

treatment:

Answer 17

Rickettsia rickettsii

• Transmitted by tick bite
• Triad: Headache, fever, rash Maculopapular rash • Starts wrists/ankles → spreads to trunk, palms, soles

Rare complications: • Encephalitis • Seizures • DIC

• Treatment: Doxycycline

Question 18

Murine Typhus

caused by:

aka:

reservoir/vector:

common in:

symptoms:

treatment:

Answer 18

Rickettsia typhi

Also called “endemic” typhus

Reservoir: Rats • Transmitted from rat fleas

Common in developing world • Flu-like illness • Rash (<50%) • Maculopapular • Starts in trunk spreads out

Treatment: Doxycycline

Question 19

Epidemic Typhus

caused by:

transmission:

symptoms:

treatment:

Answer 19

Rickettsia prowazekii

Some outbreaks in Africa during civil wars • Transmitted by body louse • Body louse lives on skin/clothes • Eggs laid on clothes and hatch • Larvae suck blood • During meal, louse defecates highly infective feces • Rickettsia in louse feces introduced to skin/membranes

Fever, chills, headaches, malaise • Maculopapular rash • Starts in trunk spreads out can progress→Confusion, seizures, coma • Treatment: Doxycycline

Question 20

Yersinia pestis

causes:

resevoir:

symptoms:

treatment:

Answer 20

Bubonic Plague

Reservoir: rats, sometimes squirrels or prairie dogs • Humans get disease from rat flea bites Human to human spread via respiratory droplets

Fever, chills, headache • Intense pain/swelling of a lymph node area (bubo)

Buboes: • Exquisite tenderness • Erythema and edema of overlying skin • Inguinal region most frequent (“bubo” = Greek word “groin”)

Treatment: Streptomycin (Doxycycline okay, too)