Spirochetes
Introduction
motile spiral-shaped organisms
Pathology: access thru abraded skin or mucous membrane
- vascular/lymphatic system, remain dormant in tissues for yrs
- host response: PMNs/macrophages/leuks
- Jarisch-Herxheimer reaction
: exaggerated reaction to bug
Þ due to cytokine response (fever, aching)
Syphilis
– Treponema pallidum
Location – worldwide
Transmission
sexually transmitted; kissing (rare); congenital infection (passage thru placenta); transfusion-assoc; accidental direct inoculation; progression in AIDS era
most infections early in the disease
gains access through mucous membrane or abraded skin Þ dissemination through lymphatics/vascular system
Clinical Manifestations
primary: chancre (painless ulcer; herpes chancre is painful!); atypical/multiple lesions in HIV ppl; chancre Þ external genitalia, cervix, mouth, parianal, anal canal
secondary (disseminated): 2-8 weeks after chancre; cutaneous and constitutional lesions; rash; adenopathy; CNS involvemnt in 40%; extensive differential diagnosis (the great imitator!)
latent: early and late
late: 2-40yrs after chancre; gummas thru-out body (destructive lesions); no feeling in feet Þ ulcers
- neurosyphilis
: meningovascular; general paresis (personality, affect, reflexes, eye, sensorium, intellect and insight, speech); tabes dorsalis
- cardiovascular syphillis
congenital: early and late; snuffles (runny nose), rash, - Darkfield exam: 1,2,congenital
Diagnosis
Biopsy specimens
Serologic testing
Nontreponemal reaginic tests (RPR, VDRL, STS)
specific treponemal tests (FTS-ABS, TPHA, MHA-TP) Þ confimatory test, very specific
Treatment
penicillin
can cause Jarisch-Herxheimer reaction
Lyme disease
– Borrelia burgdorferi
Location – northeast and mid-western USA, Europe, Scandinavia, China, Japan, Australia, Russia
Transmission – deer tick; transmission during May and Nov in all age groups
- injection into skin from tick with spread to lymph nodes and dissemination to blood and organs (synovium, retina, muscle, myocardium, spleen, liver, brain)
- invades and persists (latently or asymptomatically) in tissues for yrs
Clinical Manifestations
stage 1: ECM (erythema chronicum migrans) and assoc symptoms
stage 2: cardiac, neurologic abnormalities, musculoskeletal symptoms or intermittant arthritis
stage 3: chronic skin, nervous system or joint abnormalities
other systems affected: eye; congenital infection; hepatitis; ARDS (adult respir distress synd)
Diagnosis
large circular red lesions
culture is most definitive
Ab responses most frequent and practical diagnostic test
Treatment
Early disease: tetracycline, PCN
Lyme arthritis: oral tetracycline or amoxicillin/probenecid, IV PCN, ceftriaxone, new macrolides
Meningitis: ceftriaxone or IV PCN
Leptospirosis
– Leptosppira species
– worldwide
Transmission
Zoonosis: main host is animial;
Two Modes of Transmission:
- (1) direct contact with infected animals (esp rats)
- (2) indirect contact with water or soil contaminated with urine from infected animals
risk: occupational (farmers,vets) ,recreational (campers,swimmers)
Clinical Manifestations – biphasic Illness
- Anicteric
- 1st stage (3-7 days): fever, myalgias, headache, conjunctival suffusion; bug present in blood/CSF
- 2nd stage (0-30 days): fever, meningitis, uveitis, rash; bug present in urine
Icteric
1st stage (3-7 days), 2nd stage (10-30 days): jaundice, hemorrhage, renal failure
Diagnosis
isolate bug (blood-early; urine-late)
Treatment
Penicillin G or tetracycline
Must start by day 4 to have any effect
Relapsing fever
– Borrelia species
- Location
– worldwide; louse-borne; E- Africa, S-American Andes
- Transmission
– 2 types:
- (1) epidemic (louse borne; more fatal)
- (2) endemic (tick borne)
- Clinical Manifestations
- get recurrence/relapse due to Ag modifications on surface of bug
- recurrent fever, hepatosplenomegaly, jaundice, rash, CNS involvement
Diagnosis
demonstrate organism in blood during febrile episode
Treatment
tetracycline, chloramphenical
can cause Jarisch-Herxheimer reaction
Rat-bite fever
– Spirillum minor
Location – worldwide
Transmission – rat bite
Clinical Manifestations – fever, bite wound, regional adenitis, chills, headache, malaise, myalgias
Yaws, Pinta, Bejel
– Nonvenereal treponemes
- Location
– tropical/subtropical Africa, Latin America, Western Asia
- Transmission
– direct contact with infected human
- Clinical Manifestations
– cutaneous lesions
- bone lesions with yaws and bejel
- mucous membrane lesions with bejel
- all with 1, 2, latent and late lesions,