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Syphilis, Plague, and Lyme Disease: Definition, Transmission, Stages, and Diagnosis, Quizzes of Microbiology

Detailed information about three infectious diseases: syphilis caused by treponema pallidum, the plague caused by yersinia pestis, and lyme disease caused by borrellia burgdorferi. It covers their definitions, transmission methods, stages, and diagnostic methods. It also mentions related diseases such as rocky mountain spotted fever.

Typology: Quizzes

2012/2013

Uploaded on 08/11/2013

cantwell77515
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TERM 1
Syphilis / Treponema
pallidum
DEFINITION 1
spirochete not able to be cultured in vitro- too thin to see by Gram
stain, but contains endotoxin3rd most common ly reported
sexually transmitted disease in USAcoinfection with other
STDs is commonSF ~ 30% of early syp hilis 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 in tercourse (1/3 of exposed
become infected)transplacental (cong enital syphilis)direct
contact via epithelial & mucosal micr otraumas (infrequent)
Pathogenesislocal r eplication - dissemination by b lood &
lymphaticsinfects end othelial 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.)
pf3
pf4
pf5
pf8

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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