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Syphilis / Treponema
pallidum
spirochete not able to be cultured in vitro- too thin to see by Gram stain, but contains endotoxin3rd most commonly reported sexually transmitted disease in USAcoinfection with other STDs is commonSF ~ 30% of early syphilis patients are HIV+~5X greater in malespeak incidence is at later age than Chlamydia & gonorrheabi- & homosexual men ~65% of increaseMost common in blacks TERM 2
Syphilis / Treponema pallidum -Treatment /
prevention
DEFINITION 2 Transmissioncommonly sexual intercourse (1/3 of exposed become infected)transplacental (congenital syphilis)direct contact via epithelial & mucosal microtraumas (infrequent) Pathogenesislocal replication - dissemination by blood & lymphaticsinfects endothelial cellsswollen lymph nodes - adenopathy TERM 3
Stages/Manifestations of Syphilis
DEFINITION 3
Primary syphilisSecondary syphilisLatent syphilisTertiary
syphilisCongenital syphilis
TERM 4
Primary syphilis
DEFINITION 4
3 90 days after exposurechancehard, slightly
elevated, round, ulcerous lesion at site of entry usually
penis, labia/cervix, anorectal region, or mouth heals
spontaneously in ~3-6 weeks even in absence of
treatmentmay progress to secondary syphilis in
absence of treatment
TERM 5
Secondary syphilis
DEFINITION 5
1 - 12 weeks after chancre heals constitutional
symptoms fever, headache, myalgias, arthralgias, poor
appetite, loss of weight, loss of hairskin rash &
generalized adenopathy appearance of rash is highly
variable (macular, papular, pustular, etc.)
Secondary syphilis -Rash
usually bilateral commonly involves the palms of
hands & soles of feet rash/lesions are teeming with
spirochetes & thus potentially very infectious may
resolve spontaneously without treatment reappear at any
time or remain latent
TERM 7
Latent syphilis
DEFINITION 7 may last a few months or a lifetimeno obvious symptoms, but still infected(positive serological tests, VDRL & RPR) Early latent (<1 year) infectious, secondary syphilis may reappear high risk of passage to fetus (congenital syphilis) Late latent (> 1 year) transmission rare~ 15- 50% of untreated latent cases progressto tertiary syphilis TERM 8
Tertiary syphilis
DEFINITION 8 may occur anytime(~5 - 50 years after primary infection)granulomatous lesions gummas may occur in practically any location skin, bone, liver, etc. heart (cardiovascular syphilis) CNS & brain (neurosyphilis & dementia) gummas in critical organs may cause death non- infectious (low number of spirochetes in lesions) TERM 9
Congenital syphilis
DEFINITION 9 T. pallidum crosses placenta & infect fetus in utero75-95% chance of infecting fetusin utero - stillbirth/abortion variety of fetal abnormalitiesinfected infants may be initially asymptomatic latter develop - rhinitis (snuffles) & macular rashUntreated - developmental abnormalities of hard tissues saber shins Hutchinsons incisors & mulberry (Moons) molars TERM 10
Laboratory Diagnosis of Syphilis - Microscopy
DEFINITION 10 (1) Microscopy immediate observation of material from lesion - spirochetes w/ corkscrew motion used in presumptive diagnosis of 1syphilis in males (vaginal & oral lesions / indigenous spirochetes) may be used in males & females for diagnosis of 2 syphilisDarkfield microscopy (unstained)Fluorescent microscopy (direct immunofluorescence) stained w/ fluorescent- tagged antibody to T. pallidum
ZOONOSES
human diseases caused by microbes acquired from animals (not all veterinary diseases are zoonoses)acquired directly from the animal reservoir ortransmitted by insect vector (i.e. ticks, fleas, mosquitoes, etc)Significant causes of human diseases Many are life-threatening (ex. rabies & plague) Epidemic spread & frequently misdiagnosedThe Plague - Yersinia pestisLyme Disease - Borrellia burgdorferiRocky Mountain Spotted Fever - Rickettsia rickettsii TERM 17
The Plague - Yersinia pestis
DEFINITION 17
infectious disease of animals and humanstransmitted to
humans by bite of rodent flea carrying Yersinia pestis
TERM 18
Yersinia pestis - Identification
DEFINITION 18
facultative Gram-negative rod (Enterobactereacae
family member)bipolar staininglow infectious dose
(high #s in blood)laboratory diagnosis by lymph node
&/or blood culture
TERM 19
Yersinia pestis - Epidemiology
DEFINITION 19
endemic in a variety of animalswild rodents serve as major
reservoirtransmitted from infected rodentsto other animals
(including humans)by bite of infected fleaSylvatic
(endemic) plague in wild rodent populationUrban
(epidemic) plaguein urban rat population
TERM 20
Pathogenesis of Plague
DEFINITION 20
flea ingests Y. pestis from infected rodentwhile taking blood
mealY. pestis multiplies in flea intestinal tract - blocked flea
flea regurgitates Y. pestis in to new victim during next
bitesurvive w/i macrophagessepticemia & lymph node
enlargement (early diagnosis is critical - 50-60% fatal if not
treated rapidly)
Three principal forms of plague
Septicemic w/ or w/o regional lymph node involvement (10-15% of cases) multi-organ involvement & septic shock Bubonic involvement of regional lymph nodes (80-85% of cases) inflammation & hemorrhagic / characteristic black buboesPneumonic (~100% fatality) involvement of the lungs & development of pneumonia (2-5% of cases) transmitted person-to- person by respiratory route (fleas not needed TERM 22
Plaque - Treatment / Prevention
DEFINITION 22 Treatment streptomycin &/or tetracycline may be used prophylactically in close contacts Prevention vaccine (?) - inactivated whole bacteria - marginally effective high-risk individuals veterinarians park rangers militarysurveillance of rural rodent populations for plague urban rodent & flea control measures public education TERM 23
Lyme Disease - Borrellia burgdorferi
DEFINITION 23
1st recognized in the USA - 1975mysterious outbreak of
juvenile rheumatoid arthritisin adults Borrellia burgdorferi
1982 determined to be the etiologic agent transmitted to
humans from infected animals by Ixodes ticks
TERM 24
Borrellia burgdorferi
DEFINITION 24
long thin (~0.2 m) spirochetenot easily seen by Gram
stain & light microscopeusually observed by darkfield
microscopycan be grown in vitro in complex growth
media
TERM 25
Epidemiology of Lyme Disease
DEFINITION 25
primary reservoir white-footed mouse (& other small
mammals)transmitted by Ixodes tick deer tick(very
small, not common dog tick)to larger mammals white-tailed
deer dogs humans, etc.24-48 hr bite required for
transmission
Treatment & Prevention of Lyme Disease
doxycycline or amoxicillin for stage 1penicillin or ceftriaxone for late stagesvaccine(s) human vaccine licensed in 1999, but removed from market in 2002 (low demand?)vaccine available for dogs (used off-label for horses) management of deer populations avoid tick-infested areas (May-July, nymphs)wear light colored clothestuck in shirts, pants, etc.inspect yourself for ticks & remove promptly if found TERM 32
Rocky Mountain Spotted Fever - Rickettsia
rickettsii
DEFINITION 32
most severe & most frequently reportedrickettsial
disease in USA Rickettsia Gram-negative cocobacilli
obligate intracellular pathogensalso cause Q fever
and several varieties of typhus
TERM 33
Rickettsia rickettsii
DEFINITION 33
reservoir rodents, dogs, & other mammals vector (&
resevoir?) dog or wood ticks (can be transmitted by
transovarian route in ticks) Dermacentor variabilis in the
East Dermacentor andersonii in the West Rhipicephalus
sanguineus (? Arizona)
TERM 34
Rickettsia rickettsii - Pathogenesis
DEFINITION 34 Pathogenesis 2 - 14 days following tick bite sudden onset of persistent fever, headache, & fatigue few days latter - rash 1st on extremities (palms, soles, arms) & then on body trunkif untreated severe complications may occur CNS damage - delirium & coma septic shock(~30% death rate)overall death rate ~2-5% of infected individuals TERM 35
Rickettsia rickettsii -Treatment / Prevention
DEFINITION 35
Diagnosis symptoms & serological testsTreatment &
Prevention tetracycline no vaccine avoid tick exposure
