Systemic spirochetes Flashcards
Describe how spirochetes appear microscopically. Do they gram stain? Do they grow in vitro?
Spirochetes are spiral-shaped organisms that exhibit corkscrew motility, don’t gram stain, and grow SLOWLY in in vitro or not at all.
What are the three geneses of pathogenic spirochetes?
- Treponema (pallidum and carateum) - all susceptible to penicillin, all have same serological responses in humans
- Borrelia - zoonotic infection
- Leptospira - zoonotic infection.
Can T. Pallidum be grown in culture?
NO
Can Borrelia be grown in culture?
yes - it is fastidious and microaerophilic
Can Leptospira be grown in culture?
Yes - aerobically in the right media
Borrelia burgdorferi - what disease does it cause?
Lyme disease: tick born
What is the tick that carries Lyme disease? The animals that are important to the life cycle of this tick?
Ixodes scapularis
Ixodes dammini
Reservoirs: white footed mice and white-tailed deer
Describe the clinical manifestations of lyme disease
Early infection (STAGE 1): localized infection - ERYTHEMA MIGRANS (bulls eye rash) at site of tick bite
Early infection (STAGE 2): dissemminated infection - secondary annular skin lesions, systemic symptoms such as severe malaise and fatigue. BELLS PALSY.
Late infection (STAGE 3): persistant infection: arthritis (like one knee), meningoencephalitis, neuropathies.
How do you diagnose Lyme Disease?
Clinically: have erythema migraines or a late manifestation
Laboratory: At least one of: isolation of B. burgdorferi, Diagnostic levels of IgM or IgG antibodies to spirochetes, or significant increase in antibody titer between acute and convalescent serum samples (4x rise in titer). Serologic: ELISA - only good to detect Lyme disease from here, not europe (different strain)
What is the therapy for Lyme Disease?
Oral antibiotics for stage 1: doxycycline
Stage 2: may need IV antibiotics
Is lyme disease forever?
No. It is probably reinfection.
What bug can cause a similar rash to Lyme Diseases’s erythema migraines bull’s eye?
Southern Tick-associated Rash Illness (STARI) - by lone star tick Amblyomma americanum
What causes relapsing fever? how do you define relapsing fever?
Borrelia sp - Recurrent episodes of fever separated by asymptomatic intervals
What is the difference in vector and reservoir of relapsing fever that is epidemic and endemic
Epidemic relapsing fever: human reservoir, body louse vector
Endemic relapsing fever: rodent/soft-shelled tick reservoir, soft-shelled tick vector
How is Borrelia recurrent transmitted?
From person to person by LICE. No animal reservoir, only occurs in epidemic form.
How is Borrelia hermsii transmitted?
From animals to humans by ticks. Animal reservoir. Endemic form only.
What is the key clinical feature of distinguishing LICE born vs. TICK born recurrent fever?
LICE: greater jaundice and CNS involvement than TICK.
What causes Leptospirosis?
The spirochete Leptospira
How is leptospirosis spread?
Excrete leptospira in urine into water => infect animals and humans
What is the clinical presentation of leptospirosis?
acute febrile illness (along with conjunctival suffusion - reddening of the conjunctiva due to increased blood flow) and or meningitis
What is a major complication of leptospirosis?
Weil’s disease: jaundice and renal failure when infected with leptospirosis.
