Zoonotics Flashcards
Rickettsiae morphology
Giemsa stain rods peptidoglycan containing cell wall diaminopimelic acid (DAP) cell wall obligate intracellular
rickettsiae virulence
multiply in endothelial cells –> leakage and thrombosis
Rickettsiae Dx
#1--> serology #2 --> PCR assay #3 --> Weil-Felix reaction = not used d/t cross reactivity with Proteus
Rickettsiae Tx
sulfonamides will make it WORSE!
PNC doesn’t work
use tetracyclines or chloramphenicol
R. Rickettsii
Rocky Mountain Spotted Fever
xsmitted by the wood and dog tick (Dermacentor)
Rocky mountain rgn / Eastern and SE US
rash on trunk, soles, and palms
R. Rickettsii complications
DIC thrombocytopenia encephalitis vascular collapse renal and cardiac failure
R. akari
Rickettsial pox
xsmitted by house mouse mite
US large urban areas / Russia / Korea
R. akari clinical presentation
erythematous papules –> vesicles –> local eschar with regional lymphadenopathy
R. prowazekii
Endemic typhus
Res: humans and flying squirrels
Xsmitt via human body and head louse
Central, South America and Africa
R. prowazekii clinical presentation
2wks –> H/M/F –> 4-7d –> patchy cutaneous erythema –> maculopapular, petechial, or hemorrhagic form
rash starts at trunk and goes to extremities
does not affect the soles or palms
R. prowazekii complications
Brill-Zinsser Dz = recrudescent infection myocarditis CNS dysf(x)
R. typhi
Endemic (murine) typhus
Res: rat
Xsmit via rat flea (Xenopsylla)
rash that starts on trunk and spreads to the extremities
Oriental (R.) tsutsugamushi
Scrub typhus Res: rodents Xsmit via chiggers chills/F/H --> local vesicular lesion --> black eschar fatality 30% in untreated cases
Ehrlichia
Ehrlichiosis
Res: cattle, domestic animals
Xsmit via deer and dog ticks
SE, Mid Atlantic, S, Central US
Ehrlichia clinical presentation
Rash is UNCOMMON
F/H/M/Myalgia
leukopenia
thrombocytopenia
Yersinia pestis
Bubonic plague
SE US –> semi-arid plains
G- rods
bipolar staining via Giemsa stain
Yersinia pestis virulence
facultative intracellular parasite of macrophages
V-W antigens = antiphago
F1 antigens = antiphago
Type III secretion system –> Yops
Yersinia pestis pathogenesis
- bubonic vs pneumonic (highly contagious)
- xsmit via flea bite, human contact, resp xsmission
- organisms infect lymphatics –> hemorrhagic and supurative necrosis –> bubo formation
Yersinia pestis Tx
streptomycin and gentamicin
recovery = long lasting immunity d/t CMI and opsonizing Ab
formalin-killed vaccine no longer used in US
Francisella tularensis
tularemia / rabbit fever / deerfly fever / rabbit skinner's dz G- coccobacillus growth on sulfhydryl compound media facultative intracellular Dx via serology Tx with strepto or gentamicin long lasting CMI upon recovery attenuated partially protective vaccine available
Francisella tularensis pathogenesis
- infection –> invasion of macro, necrosis and GRANULOMA formation
- ulceroglandular = most common / ulcerating, necrotic plaque
- glandular = vector borne / regional lymph enlargement / no skin lesions
- oculoglandular = conjunctivitis with lymph involvement
- typhoidal = most severe / bacteremia with organ seeding / resembles TB or brucellosis
Brucella (suis, abortus)
brucellosis (undulant or Malta fever) G- coccobacilli aerobic catalase and oxidase + growth on trypticase-soy agar w/ CO2 facultative intracellular
Brucella (suis, abrotus)
Xsm: contam milk, droplets, skin contact mult in phago cells --> nodes --> blood --> organ seeding GRANULOMATOUS nodules and abscesses undulating fever with night sweats palpable spleen Dx via serology via agglutination
Pasteurella multocida
cat-scratch disease
G- coccobacilli
non-hemolyitic mucoid colonies on blood agar
diffuse cellulitis w/ erythematous border
