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19 Cards in this Set

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What are Borrelia?
It is a corkscrew shaped bacterium, and are larger than treponema.
They cause Lyme disease and relapsing fever, and transmitted by insect vectors.
How is Lyme disease spread?
It is spread via the Ixodes tick. It takes greater than 24 hours of attachment for organism transfer.
Animal reservoirs include the white footed mouse and whiter tailed deer. The ticks pick up the bacterium from these animals.
What are the three stages of Lyme disease?
1. early localized stage
2. early disseminated stage
3. late stage
What is the early localized stage?
This begins about 10 days after the tick bite and lasts about 4 weeks. The skin lesion at the bite is called erythema chronicum migrans, and there are mild flulike symptoms.
What is the disseminated stage?
The organism disseminates(Borrelia burgdorferi) to 4 organ systems, the skin, nervous heart joints.
It can invade the brain resulting in meningitis, cranial nerve palsies(7th nerve) and peripheral neuropathies.
Is the heart involved in Lymes disease?
cardiac abnormalities can occur in about 10% of patients. Most common is atrioventricular nodal block with /without myocarditis. A permanent pacemaker is sometimes necessary.
App. 6 months after infection, arthritis may occur.
What occurs in the late stage?
About 10% of untreated patients will develop chronic arthritis that lasts for more than a year. The knee is often involved.
Many of these patients have the B cell alloantigen HLA-DR(1+4). Encephalopathies occur and memory impairment irritability and somnolence.
How is the diagnosis made?
1. Doctor recognition
2. If patient presents with ECM, the leading edge of the rash can be biopsied and cultured for Borrelia.
3. Elisa/western blot
How is Lyme disease treated?
Doxycycline or penicillin family.
vaccines-Imulyme/Lymerix
(they pass antibodies in the individual blood into the biting tick. The antibodies neutralize bacteria in the tick before they can be transmitted to the human.
What is Borrelia recurrentis?
Also known as "relapsing fever",it is transmitted to humans via the body louse(Pediculous humanus).
This bacteria disseminates via the blood. A high fever develops with chills and headaches.
Fever resolves in3-6 days. patient is afebrile for 8 days or so and then relapses.
What causes the relapsing episodes?
Antibodies bind specifically to the Borrelia surface proteins and remove the Borrelia from the blood.
However, this agent can change its surface proteins, and antibodies no longer recognize them, elicting new antibodies with new interleukin pyrogens.
What is the standard therapy?
Doxycycline/Erythromycin
What is Leptospira?
They are long thin aerobic spirochetes that are wound up in a tight coil. They have hooks on one or both ends, and are divided into 2 species.
What are the 2 species of Leptospira?
1. Leptospira interrogans- causes human disease and is divided into 23 serogroups.
It is found in the urine of dogs, rats livestock and wild animals. They can penetrate abrade skin either directly or orally.
2. Leptospira pomonas.
Clinically, there are 2 phases. What occurs in the first phase?
This is the Leptospiremic phase, the bacteria invade the blood and CSF causing spiking fevers malaise and bodyaches. The conjunctiva are red and there is photophobia.
What is the 2nd phase?
This phase correlates with the appearance of IgM antibodies.
Patients may develop meningismus and the CSF reveals elevated WBC count.
What is Weil's disease?
Caused by L. interrogans, (serogroup icterohemmorhagica) causes jaundice, which may involve renal failure, and hepatitis and organ hemmorhage.
How is Weil's disease diagnosed?
It is diagnosed via culture(blood and CSF via special culture) Urine may be cultured in the 2nd phase.
What is the therapeutic protocol?
Treatment must be initiated quickly. Penicillin and Doxycycline are used routinely at the appropriate times.