Other Zoonotic & Vector-Borne Diseases Flashcards
Zoonoses
Infections normally found in nonhuman vertebrates that are
transmitted to humans
Franciscella tularensis
“Rabits eat tulips”
Rabit fever
Tularemia = ulcers at the site of infection, fever, and weight loss
Glandular fever (think EBV/mono fever)
Small gram (-)
coccobacilli
stains poorly
Faculatative intracellular
Requires cysteine
Franciscella tularensis
Transmission of Franciscella tularensis
Highly infectious (alert lab before sending sample for serology)
Hard Tick bites, Exposure to mucous membranes, Aerosol (has been used as germ-warfare), Ingestion
Diseases transmitted by hard ticks
Lyme disease
Rocky Mountain spotted fever
Tularemia
Colorado tick fever
Human tick-borne ehrlichiosis
American babesiosis
Tick paralysis
STARI (Southern tick-associated rash illness)
Anaplasmosis
Diseases transmitted by soft ticks
Tick-borne relapsing fever
Types of infections with Franciscella tularensis
Ulceroglandular (most common, skin)
Oculoglandular
Pneumonic (30% fatal)
Typhoidal (ingestion)
Why is Franciscella tularensis a good biological weapon?
Low infectious dose
Severe disease
Airborn transmission
Who is at risk for Franciscella tularensis
Rabit hunters
Kids who run over rabits while mowing the lawn
Lab workers
Veterinarians
Undulant fever after drinking unpasteurized milk
Brucella suis
Brucella suis
Humans: facultative intracellular parasites of RES
Animals: GU pathogens shed in milk (no vector)
Enter via mucous membranes, skin, ingestion/inhalation; engulfed by PMNs and macrophages; travel to regional lymph nodes; multiply in macrophages; phagocyctic cells of RES; killed by phagocytic cells or contained within granulomas (prone to recurrent bacteremia)
Which profession is most at risk for acquiring Brucella suis?
Lab workers
Complications of Brucella suis
Fever, night sweats, headache, chills, myalgias, and weight loss
Hepatic lesions, arthritis, meningitis, endocarditis
Lymphadenopathy + new kitten
Bartonella henselae (flea vector)
Trench fever + Vector
Bartonella quintana (body louse)
Carrion’s disease
Limited to the Andes (Peru)
Bartonella bacilliformis (sand fly vector)
1st phase: Oroya fever (hemolytic anemia)
2nd phase: Verruga peruana (Peruvian warts)
Febrile bacteremia
Trench Fever (5 day fever)
Bartonella quintana
Immunocompromised = bacillary angiomatosis + endocarditis
Girl scratched by cat
Two-week history of swelling behind her ear
Diagnosis/confirmatory test/treatment?
Bartonella henselae
Serologic analysis
Lymph node drainage + azithromycin
Vector for brucella?
Does not have one
Can grow on artificial media
Found in RBCs
Bartonella
Obligate intracellular bacteria
Transmitted by arthropods
Rickettsiaceae
Tick-borne Rickettsia
Rickettsia rickettssii (RMSF)
Mite-borne Rickettsia
Rickettsia akari (Rickettsialpox)
Orientia tsutsugamushi (scrub typhus)
Louse-borne Rickettsia
Rickettsia prowasekii (epidemic typhus)
Flea-borne Rickettsia
Rickettsia typhi (murine endemic typhus)
Gram - coccobacilli
Requires host cell for many functions
Movement from cell to cell involves actin polymerization
Rickettsia
Pathogenesis of Spotted Fever and Typhus (the two groups of Rickettsia)
Vasculitis
Proliferation of the organisms in the endothelial lining of small arteries, veins, capillaries
Skin rash + Severe headache
EM slide with comet-like tail
Rickettsia
Do not confuse with comet-tail from ultrasound (pulmonary edema)
Which age group is most susceptible to RMSF (Rickettsia rickettssii)?
Age 0-9 are 5x more likely
Most effective treatment for RMSF
Doxy
Common misperceptions about side effects. Short courses = no problems with tooth staining or weakening of enamel
Rash that looks like chicken pox
Eschar at site of bite
Rickettsia akari
Do not confuse this eschar with that of anthrax
Rickettsia prowazekii
Prowazekki
Places of war (Somalia)
Causes epidemic typhus
Typhus means “smoky/hazy” (describing complications in the mind)
Signs of meningoencephalitis begin with the rash and continue into the 2nd or 3rd weeks. Other signs of meningoencephalitis include sensitivity to light or photophobia, delirium or altered mental status, or coma
Military importance in Vietnam
Orienta tsutsugamushi
aka Scrub typhus
Rickettsia typhi
Murine/Endemic typhus
Form of typhus transmitted by fleas (Xenopsylla cheopis), usually on rats
Obligate intracellular
Survive in cytoplasmic vacuoles of mammalian hematopoetic cells
Anaplasmataceae (Anaplasma & Ehrlichia)
Contrast with Rickettsia/Orienta that live in endothelial cells
Transmitted by the lone star tick
Inclusions in monocytes/macrophages
Headache, Muscle Ache, Fatigue
Ehrlichia chaffeensis (HME)
What does Ehrlichia chaffeensis (HME) do?
Blunts the immune system, allowing opportunistic infections to take over
Inclusions in granulocytes
Transmitted by Ixodes tick
Anaplasma phagocytophilum
Transmitted via tick feces or cattle placenta
Flu-like symptoms
Diffuse perspiration
Q fever
Coxiella burnetti
Other complications of Coxiella burnetti
Atypical pneumonia
Rarely, endocarditis
Can occur decades after initial infection
Any question that mentions armadillos
Mycobacterium leprae
