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89 Cards in this Set
- Front
- Back
What is the only contagious acid fast bacilli?
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mycobacterium tuberculosis
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which mycobacterium of them all is most commonly isolated?
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m. tuberculosis
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what bacteria is the leading cause of worldwide death?
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Mycobacterium tuberculosis
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What happens in the course of the disease tuberculosis?
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1. Macrophages/PMNs trying to rid AFB form tubercle.
2. Tubercle may liquify, form AFB-filled cavity in lungs. 3. Symptoms manifest as chronic cough and low fever. |
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What are the symptoms of tuberculosis?
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-Chronic cough
-LOW-grade fever |
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What is Miliary tb?
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Tb disseminated beyond lungs due to tubercles rupturing.
-Indicated by positive urine. |
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2 types of TB skin tests:
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-Mantoux
-Tine |
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What is the preferred TB skin test?
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Mantoux
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Why is Mantoux preferred to Tine for Tb skin test?
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Mantoux is a good deep injection; the Tine uses a disk w/ little needles- less sensitive of test.
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What is done if a TB skin test is +?
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Chest x-ray; to see if tubercle is visible. (lesion) If no lesion is visible it's possible that a vaccine caused the postiive skin test.
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What are the first line oral drugs for treatment of Tb?
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-Isoniazid INH
-Rifampin RIF -Pyrazinamide PZA -Ethambutol EMB |
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What injectable drug treats Tb?
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Streptomycin
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What AFB species is found in cows?
Disease it causes? |
Mycobacterium bovis
Disease similar to Tb, but rare in U.S. |
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What is BCG?
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an attenuated strain of M. bovis that is a vaccine for TB in endemic areas.
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What are the four Runyon groups?
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-Photochromogens
-Scotochromogens -Non-photochromogens -Rapid growers |
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Distinguish. characteristic of Photochromogens
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Develop a yellow-orange pigment only when exposed to light, after growth.
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2 species of Photochromogens:
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Mycobacterium kansasii
M. marinum |
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What disease does M. kansasii cause, what group is it in?
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photochromogens; causes a chronic disease similar to Tuberculosis
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What disease does m. marinum cause, what group is it in?
what specimen do you test for it? |
Skin disease from a water source; called swimming pool granuloma.
Skin specimen, incubated at 30 C |
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Distinguishing feature of Scotochromogens:
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produce a pigment in the DARK - before exposure to light
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2 species of scotochromogens:
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M. scrofulaceum
M. gordonae |
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What does M. scrofulaceum cause?
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scrofula of the neck - lymph node inflammation.
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what is M. gordonae known for?
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being a tap water contaminant; it can show up on a gram stain as a result, so we use distilled H2O.
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What is the distinguishing feature of non-photochromogens?
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they do not produce a pigment in either light nor dark
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what species of runyon group three is a very common isolate in AIDs patients?
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M. avium intracellulare complex
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What disease does M. avium intracel. complex cause?
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Pneumonia, or it disseminates to the skin, intestine, liver, and bone marrow.
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Where are M. ulcerans and M. haemophilum commonly found?
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on skin/in skin ulcerations of AIDS patients
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What is the disting. feature of Runyon group four?
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Rapid growers - they grow within 7 days.
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what is the most frequently isolated species of the rapid growers?
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M. fortuitum
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What does mycobacterium fortuitum cause?
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Soft tissue and bone infections after an injury
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Which of the rapid growers is a questionable pathogen
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M. smegmatis
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5 methods for identifying Mycobacterium Species:
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1. Biochemical
2. HPLC (hipress. liq. chrom) 3. BActec/ESP/BacTAlert 4. Nucleic acid probe 5. PCR on specimen |
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Fast method of Mycobacterium species id:
what is it? |
BacT Alert, Bactec, ESP
-detects the rate of growth of the bug |
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What bug causes leprosy?
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Mycobacterium leprae
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another name for M. leprae
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Hansen's bacillus
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2 forms of leprosy:
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-Lepramatous
-Tuberculoid |
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Symptoms of Leprosy
-Lepramatous -Tuberculoid |
Lep: bacilli are just under the skin surface and cause deformity.
Tub: bacilli infect nerve cells; skin turns to parchment w/ no sensation |
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How do you diagnose Leprosy?
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Test for mycobacterium leprae;
-AFB smear -Grow it - but only In Vivo; in an animal. no labs can grow it. -By process of elimination |
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What bacteria is found in Armadillo footpads?
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M. leprae
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What disease is Mycobacterium paratuberculosis possibly associated with?
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Crohn's disease
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How is M. leprae transmitted?
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through EXTENDED, close and direct contact.
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What's a key biochemical trait of M. tuberculosis?
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It's always niacin positive, and the only Mycobact. (fortuitum is -/+)
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What is the distinguishing requirement for a bacteria to be spirochete?
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Bacillus with a minimum of 1 coil
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name of the antigen common to all spirochetes:
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Reiter protein - useful in identification
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What type of microscopic examination do you do for spirochetes?
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Darkfield; reflected light shows the organism as a light area on the slide.
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What fact re: spirochetes makes lab i.d. difficult?
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it can't be grown in lab
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what is the second most commonly isolated mycobacterium species?
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mycobacterium avium intracellulare complex (MAIC)
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what are the 3 genera of spirochetes?
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-Borrelia
-Leptospira -Syphilis |
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What disease does Borrelia burgdorferi cause?
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LYMES disease
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Where was lyme's disease discovered?
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Old Lymes, Connecticuit
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How is lyme's disease transferred?
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by a vector - deer ticks; in places with high populations of white-tailed deer
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what are the three stages of symptoms of lyme disease?
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Stage 1: Skin lesion called erythema chronicum migrans; flu-like symptoms.
Stage 2: Neurologic or cardiac abnormalities. Stage 3: Arthritis |
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How is lyme disease diagnosed/detected?
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-by detection of antibody
-culture (but its not practical) -PCR (but there arent any specs to test) |
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Is there a treatment for lymes disease?
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YES -Doxycyline for 14-21 days;
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What causes fusospirochetal disease?
Another name? |
Vincent's angina;
caused by Borrelia + fusobacterium, they are in a symbiotic relationship. |
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What are the symptoms of Vincent's angina?
How do you confirm the diagnosis? |
Gingivits with a pharyngeal membrane.
Confirmed with a direct smear from membrane - you'll see the fused complex. |
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What are the three diseases caused by Borrelia?
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-Lyme disease
-Vincent's angina -Relapsing fever |
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What is relapsing fever caused by?
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9 different Borrelia species
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How is relapsing fever transmitted?
What kind of disease is it? How is it detected? |
-ticks and lice;
-a Fevrile disease w/ a fever for 3-7 days, goes down, then goes back up. -seen on a blood smear, so not detected in the microbiology lab, but haematology |
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What disease is caused by Leptospira, and what is it?
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Leptospirosis; a zoonotic FEBRILE disease from rodent droppings.
(causes fever) |
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What is unique about the Leptospira genus compared to Borrelia and Treponoma?
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It can be cultured in lab
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What type of media is used for a Leptospira culture?
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-Fletcher's media.
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Incubation conditions for leptospira:
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Fletcher's media, 30'C, up to 6 weeks.
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What is the primary method of identifying Leptospira?
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Serological tests for Antibody in the patient; not done in a typical lab, sent off to others.
NOT id'd with culture or stain. |
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what causes syphilis?
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Treponoma pallidum
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what is the most common species of Treponoma?
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Treponoma pallidum
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How is syphilis transmitted?
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1. direct sexual contact
2. Congenitally; passes through the placenta during fetal development |
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What type of symptoms does an infant have when born with congenital syphilis?
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2ndary symptoms - rash
Maybe Hutchinson's teeth |
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What do the 4 symptomatic phases of Syphilis consist of?
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1. Hard chancre
2. rash 3. no symptoms 4. gummas |
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When are symptoms seen after initial Syphilis infection?
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on avg, 3 weeks; can be 10-90 days
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What happens during Primary Syphilis?
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Hard chancre on genitalia, in mouth.
Disappears as bug goes into circulation. A lesion smear is most reliable at this stage. |
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Problems with doing a lesion smear during primary syphilis:
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-Other treponomas are normal flora; won't be abnormal to see on slide.
-Must use darkfield microscopy - not used to it, may have error. |
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Common I.D. method for Primary Syphilis:
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Immunoflourescent stain from a Chancre lesion smear
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What happens in 2ndary Syphilis - Symptoms, timecourse, then what?
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-Rash appears mainly on trunk
-Represents hematogenous dissemination of the bug -Appears 2-8 wks after chancre, resolves in 2-10 wks. Serological identification is very reliable at this point. |
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When can/can't you do a Serological assay for antibody during Syphilis?
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NOT during primary - 25% of positive patients will test negative! Use FTA-ABS
YES during 2ndary - dissemination, bug is everywhere in blood. |
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What happens in latent syphilis?
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-Rash rarely re-appears,
-No symptoms visible. |
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What happens in Tertiary Syphilis?
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GUMMAS develop - tissue lesions (CNS, Cardiovasc).
Cause loss of musc. coordination, congenital heart failure, seizures, and you go insane. |
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How is Syphilis treated?
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In Primary/Secondary phases, very susceptible to Penicillin, one large dose intramuscularly.
In 3ary, longer treatment necessary. Gummas are irreversible. |
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Main way to diagnostically test for Syphilis?
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(Treponema pallidum)
Serological test on serum/plasma |
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2 broad categories of serol. testing:
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-Non-treponemal tests - for reagin.
-Treponemal Ab tests - for Ab. |
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2 types of Non-treponemal tests:
-what is this type of testing? -Why is it done? What does it show? |
Screening. Shows every possible positive, and then some. Lots of false positives, but no false negatives.
1. VDRL (Venereal dis. research lab) 2. RPR (Rapid plasma reagin) |
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What is Reagin?
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Produced in response to tissue damage, which occurs in Syphilis - chancre
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What are 2 Treponomal Ab tests?
What are they for, what do they tell? |
1. FTA-ABS (flouresc. treponemal antibody-absorbed)
2. Hemagglutination (MHATP) Confirmatory tests, directly for treponema pallidum, no false positive. |
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Why do screening instead of just confirmatory testing for Syphilis?
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Screening is faster, easier to perform, and there are no false negatives.
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What Treponema species causes YAWS?
What is YAWS? |
-Treponema pertenue
A skin disease in the tropics that causes hyperplasia - very very gross!! |
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Where are other Treponemes normal flora?
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-Mouth
-Vagina -Intestines |
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Which Treponeme is never normal flora?
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Treponema pallidum
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Pharyngeal membrane, gingivitis
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Vincents Angina
Fusobacterium Borrelia |
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SYPHILIS:
(transmission reminder) |
not just an STD; babies get it too
Sex w/ the whole course Congenital w/ secondary symptoms |