Borrelia & Leptospirosis Flashcards
(31 cards)
Describe Borrelia
Large spirochetes
Can see on blood smear as they are ciruclating in blood
Serologic test for specific dx
Plasmids code for outer membrane protein antigens
What is the characteristic diseases associated with Borrelia species?
Relapsing fever- B.recurrentis
Lyme Borreliosis- B.Burgdoferis
How does B.Recurrentis avoid the immune system?
Antigenic diversity of their structures using genes on plasmid -> leads ot relapsing fever
When is relapsing fever seen epidemically? endemically?
Epidemic: catastrophe like war/famine
Endemic: Tick borne relapsing fever in mountainous regions in western US
How does the transmission and cycle of relapsing borrelia differ between B.REcurrentis and other Borrelia species?
B.Recurrentis: Louse borne -> suck blood -> crush louse- > transmit infection
Borrelia Species: Tick borne -> feed on rodent -> transovarial passage in ticks -> humans are accidental host here
What are the clinical presentaitons of relapsing fever?
Fever Chills Muscle Pain HA Relapse: resolves 3-5 days, remits after 7-9 days with decreasing severity with each relapse
How is relapsing fever treated
Tetracycline, Erythromycin
J-H reactions commonly seen
How is relapsing fever diagnosed?
Blood smear
Serology
What is lyme borreliosis?
Systemic spirochetal disease that resembles syphilis
Prominently involves skin and CNS
B.Burgdoferi
What are hte primary reservoirs of B.Burgdoferi?
Deer and mouse
How is B.Burgdoferi spread?
Ixodes Ticks (nymph form in spring/summer)
Where in the US is lyme disease most prominent?
Northeast
Describe the pathogenesis of Lyme Borreliosis
Tick bite -> B.Burgdoferi -> multiply locally -> enter lymph/blood -> dissemination
Antibody leads to disappearance of spirochetes -> immune pathogenesis in late stage
What is the characteristic of Early Stage Lyme Disease?
Erythema Migrans: expanding erythematous lesion at site of tick bite with flu like illness
Bull’s Eye lesion
What is the presentation of early disseminated lyme disease?
Occurs days-weeks after primary infection
Fatigue, HA, fever, malaise
Multiple skin lesions
Neuro: ISOLATED FACIAL NERVE PARALYSIS, Meningitis
Cardiac: Heart Block, myocarditis
Arthritis: occurs in 60% untreated much later
What happens in late stage lyme disease?
Arthritis: recurrent pain and swelling in large joints esp KNEE
Encephalopathy: maybe?
Skin: Acrodermatitis Chronic Atrophicans (flat, fragile scar on skin)
How is Lyme Borreliosis diagnosed?
Can’t use culture
ELISA mostly now -> if positive-> confirm with Western Blot
PCR
How is hte positive serologic test related to infection stage of lyme disease?
Acute EM: 30-40%
Convalescent: 60-70%
4-6 weeks post infection: 90%
If clinical findings sufficient-> treat before positive testing results
How is Lyme Borreliosis treated?
Early: Doxycycline, Amoxicillin, Cefuroxime Oral
Late: Oral same as early or IV PEN-G or Ceftriaxone
How can Lyme borreliosis be prevented?
Repellants
Tick checks
How long do ticks have to be attached for intfection to be transmitted for lyme borreliosis?
24 hours
How long does hte tick need to cause relapsing fever in B.recurrentis infeciton?
Just a few minutes
What is leptospirosis?
Zoonosis spirochete
Variety of animal reservoirs
Humans get via contact with infected animal urine usually contaminated water
How does leptospirosis look structurally?
Thin spirochete wiht hook on one or both ends
