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26 Cards in this Set

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Describe SPIROCHETES?

A) What is their shape and structure?

B) How do they replicate?
A) They are elongated, flexible, and motile; twisted spirally on their long axis (helicoid)

They possess a flagellar structure (axial filament, or internal flagellum spirally wound around the cell and anchored through hooklike bases at the two poles of the cell)

B) Multiply by BINARY FISSION
What are the 3 major groups of SPIROCHETES that cause human disease?
1) GENUS TREPONEMA - causes SYPHILIS, yaws, and pinta; also non-pathogenic organisms in this genus are found in the oral cavity, intestine, and genitalia of both humans and other animals

2) GENUS BORRELIA - cause of relapsing fever and Lyme Disease, named after French biologist, Borrel

3) GENUS LEPTOSPIRA - causes of leptospirosis
* What are the GENERAL CHARACTERISTICS of TREPONEMA PALLIDUM?

1) What human disease does it transmit?

2) How long/ wide is it? Can you view it under scope? Gram stain?

3) Can it be kept in culture? How long can it keep for?

4) How can you kill it and with what? AND...
1) Agent of HUMAN SYPHILIS

2) 5- 15 microns long, with a width of .2 micrometers, which is less than the resolving power of the light microscope and hence cannot be seen by gram staining- - but has a structure that is like that of a GRAM- NEGATIVE bacteria

3) Live organisms cannot be grown in culture, but can be kept motile for several days in very rich media, under anaerobic conditions; it will survive whole blood for only about 24 hours, or tissue specimens for several days (so it cannot survive in blood stored for several days)

4) It can be EASILY KILLED by heat, drying, soap, and water, but the bacteria can be stored at - 80 degrees C for many years, and then revived- - perpetuated in lab by being injected into the testicular tissue of rabbits
* How do you TRANSMIT TREPONEMA?
1) Transmit via GENITALIA or MUCOUS MEMBRANES- - but is not transmissible during the late stages of the disease

2) Can also be transmitted from MOTHER TO FETUS- - "congenital syphilis" which is a serious pathological consequence to the child; still birth, abortion, or general signs at birth generally similar to secondary syphilis

3) Also via TRANSFUSION - - if recipient of FRESHLY obtained blood or from cuts
* DIAGNOSIS

What is the PATHOGENESIS of the TREPONEMA?

a) Incubation?

b) Primary lesion?

c) Secondary lesion?

d) Tertiary lesion?
a) INCUBATION: 2-6 weeks
Clinical evidence of the disease is absent, but bacterial replication at the site of entry as well as secondary sites is very active

b) PRIMARY LESION: usually appears 1- 4 weeks after infection, typically on genitalia, accompanied by focal lymphadenopathy- - heals spontaneously 1- 5 weeks after appearance

c) SECONDARY LESION: organism has dissemincated
Generalized skin rash or mucousal lesion erupts as early as 2 weeks or as late as 20 weeks after the primary lesion first appears
This phase may result in ARTHRITIS, RENAL DYSFUNCTION, or other abnormalities

d) TERTIARY LESION: occurs late disease- - many years after initial infection, adn may occur in CNS, AORTIC VALVES, and other locations

Generally do not see the organisms
2) What is the significance of exposure?
2) Important in aid of diagnosis
3) How do you demonstrate organisms in lesions?

4) Serologic test
It involves darkfield examination of exudate from an open genital lesion, or from "secondary lesions"
4) What are the 2 serological tests performed? (1)
a) EARLY TESTS

"WASSERMANN ANTIBODY" reacts wth a specific lipid: diphosphatidylglycerol to which is added lecithin and cholesterol

Complement fixed in reaction, and degree of fixation measured

Subsequently modified as flocculation tests

Origin of antigen that infected individual actually makes antibodies against unknown

b) MODERN TESTS
1) NONSPECIFIC: which is very sensitive and genreally done first
i) Screening tests widely used: VDRL with cardiolipin
ii) Newer version: RPR in which ag is absorbed to carbon particles, making clumping easier to detect

2) SPECIFIC tests: generally used to confirm results of the nonspecific tests

(see notes for details!)
What about FLASE POSTIVES AND NEGATIVES?
*
* What ANTIBIOTICS do you use to treat TREPONEMA?
PENECILLIN
* VACCINES?
None yet!
What are 3 other TREPONEMAL DISEASES? (see notes for details)
1) YAWS- - like t. pallidum, non veneral, and less serious

2) BEJEL- - similar to YAWS, non venereal, common disease among children from Syria

3) PINTA- - disease of central and south america, rarely serious, and causes non- ulcerating lesions in hands, feet, and scalp
* Describe BORRELIA.

1) What disease does it cause?

2) What is the course of the disease?

B. HERNSII?

B. RECURRENTIS?

3) What is the diagnosis based on?
1) RELAPSING FEVER is caused by any of a dozen different species of BORRELIA- - can't grow on artifical media, but can grow in a chick embryo

B. HERNSII is endemic in the western US, and is transmitted by ticks to rodents, and then to man

Its natural resevoir is in WILD RODENTS

B. RECURRENTS is epidemic, not found in the US and involves transmission from human to human

2) COURSE OF DISEASE: FEVER 4- 5 days, afebrile for 7- 10 days, then fever recurs and disappears again- - have 3- 10 replapses before you recover again

3) Its DIAGNOSIS is based on CLINICAL SYMPTOMS and OBSERVATION of BORRELIA organisms in stained blood smears of darkfield microscopy
What is LYME DISEASE caused by?
LYME DISESASE is caused by BORRELIA BURGDORFERI, and it's the most COMMON tick-borne disease in the US

ENDEMIC on the EAST COAST and PACIFIC NORTHWEST

Its major RESEVOIRS are WHITE- FOOTED MOUSE and WHITE- TAILED DEER

Carries about 7 linear and 2 circular plasmids
What are the 3 stages of PATHOGENESIS for LYME DISEASE?
1) FIRST: papule with expanding erythema 3- 14 days after bite- - fever, headache, stiff neck, malaise

2) SECOND: various neurologic and cardiac involvement

3) THIRD: migrating episodes of arthritis- - occurring weeks to months after tick bite and may last several years
How do you DIAGNOSE LD?
based on thses symptoms and expanding bright red rash- - difficult to isolate the organism- - diagnostic ELISA test to detect circulating antibodies against B. BURGDORFERI is available
What is a LATE MANIFESTATION OF LD?
without treatment you can get chronic arthritis for 3- 5 years after first symptoms, and those with HLA- DR that don't respond well to tetracyclin
TREATMENT?
TETRACYCLIN

AMPICILLIN is safe for young children
VACCINE?
a vaccine has been developed for people with a high risk of being exposed to LD
What did we find out about IRON?
just found out that B. BBURDORFERI does not have a requirement for iron, so there is noevidence of iron uptake systems and no iron requiring enzymes- - but seem to have high requirement for MANGANESE REQUIRING METALLOENZYMES
* DESCRIBE LEPTOSPIRA.

Is it a common disease?

How is it transmitted?

What are different symptoms of the disease?

Who are most at risk of getting the disease?
LEPTOSPIRA is an UNCOMMON human disease by RATS, DOGS, and other animals usually form infected urine.

Transmitted thorugh skin or upper alimentary mucousa, and it is NOT ARTHROPOD BORNE

Manifestations of LEPTOSPIROSIS include NEPHRITIS, JAUNDICE, MENINGITIS

Multiple serotypes can cause disease, and is an occupational hazard for house workers or people in rat infested areas
PATHOGENEISIS of LEPTOSIROSIS
enters the blood and invades various tissues and organs, particularly the KIDNEY, LIVER, MENINGES, and CONJUNCTIVA
SYMPTOMS?

What is WEIL'S DISEASE?
MUSCULAR PAIN, HEADACHE, PHOTOPHOBIA, FEVER, CHILLS

WEIL'S DISEASE is an infectious jaundice caused by one serovar- - and it leads to renal failure, hepatic injury with a fatality rate as high as 25%
DIAGNOSIS OF LEPTOSIRA?
can be grown and identified by serological methods
TREATMENT?
PENECILLIN, ERYTHROMYCIN, TETRACYCLIN
VACCINE?
none for humans