Bacterial zoonoses II Flashcards
What is the shape for borrelia?
Long spirochete
What causes Lyme disease in the US?
Borrelia burgdorferi
What is the main vector for Lyme disease?
Ixodes spp. (hard tick)
What is the characteristic presentation of a borrelia burgdorferi bite / infection?
Bull’s eye rash
What characterizes late infection of borrelia burgdorferi?
Arthritis - one or more joints, skin discoloration, neurologic complaints
What is the treatment for early stage Lyme disease? Late stage?
- Early stage - cefuroxime + doxycycline + amoxicillin 2. Late stage - ceftriaxone + doxycycline + amoxicillin
What are the two types of relapsing fever?
Epidemic and endemic
What is the cause of epidemic relapsing fever?
Borrelia recurrentis (louse-borne)
What is the cause of endemic relapsing fever?
Borrelia hermsii (tick-borne)
How does borrelia evade the immune system during relapsing fever infection?
Antigenic variation
Is epidemic relapsing fever a zoonotic disease?
No - human to human
What is the treatment for relapsing fever?
Tetracycline or erythromycin
What is the gram stain for rickettsia?
Gram negative (weakly)
What is the pathogenesis of rickettsia?
- Organisms infect vascular epithelium of small blood vessels 2. Facilitate own entry into host cell 3. Escape vacuoles and enter cytoplasm 4. Limited ability to survive outside host cell
How does rickettsia manifest in the skin?
Inflammation, thrombosis, erythrocyte leakage - rash or petechia
How does rickettsia manifest in systemic disease?
Vascular lesions throughout body, dependent on virulence and tissue tropism of strain / species involved
What are the vectors for rocky mountain spotted fever?
Dog tick, rocky mountain wood tick
When are most cases of rocky mountain spotted fever reported?
Between April and September
How does rocky mountain spotted fever present?
- Fever 2. Rash 2-5 days after fever - small flat pink non-itchy spots on wrists, forearms, and ankles
What type of spread is associated with rocky mountain spotted fever?
Centripetal
What is the presentation of untreated rocky mountain spotted fever?
Disseminated intravascular coagulation, thrombocytopenia, pulmonary edema, renal failure, GI hemorrhage, shock
What is the treatment for rocky mountain spotted fever?
Tetracycline (doxycycline)
What is the gram stain for ehrlichia and anaplasma?
Gram negative (weakly)
Ehrlichia and anaplasma primarily parasitize what cell types?
Monocytes and granulocytes
What are morulae?
Colonies of ehrlichia / anaplasma inside vacuoles
What causes human monocytic ehrlichiosis (HME)?
Ehrlichia chaffeensis
What causes human gradulocytic ehrlichiosis (HGE)?
Anaplasma phagocytophilium
What protects ehrlichia and anaplasma from humoral immune response?
Intracellular location
What is the pathogenesis of ehrlichia / anaplasma infection?
Derailment of phagolysozome maturation
What leads to resolution of ehrlichia / anaplasma infection?
INFy-mediated activation of macrophages
What is the principle vector for human monocytic ehrlichiosis?
Lone Star Tick
What is the principle vector for human granulocytic ehrlichiosis?
Ixodes tick
Which is the treatment for ehrlichiosis?
Tetracycline (doxycycline)
What is the gram stain for coxiella burnetii?
Gram negative
Coxiella burnetii causes what disease?
Q fever
Q fever is caused by what organism?
Coxiella burnetii
What is the pathogenesis of coxiella burnetii?
Reside and replicate within fully acidified phagolysosomes of macrophages and monocytes (do not derail their formation)
Which variant of coxiella burnetii can survive harsh condition, similar to a spore?
Small cell variant
What is the treatment for Q fever?
Tetracycline (doxycycline)
What is the gram stain for bartonella?
Gram negative
What is the shape of bartonella?
Rod
What causes trench fever?
Bartonella quintana
What causes cat scratch fever?
Bartonella henselae
How is trench fever transmitted?
Body louse - bacteria excreted via feces then rubbed into skin / wound by scratching the bite
What is the treatment for trench fever?
Aminoglycoside (gentamicin) or macrolide (erythromycin)
How is cat scratch fever transmitted?
Inoculation of flea feces into a cat scratch or bite
What type of fever is associated with brucellosis?
Occurs daily, recurs in the evening, normal by morning, ends in a drenching sweat
What type of fever is associated with borrelia?
Occurs every 7-10 days, lasts 7-10 days
