42-Treponema, Borrelia and Leptospira

Question 1

What is the structure of a spirochete?

Answer 1

• Spirochetes are tightly coiled with pointed, straight ends. Three periplasmic flagella are at each end. The spirochetes are too thin to be seen with light microscopy, but they can be visualized by darkfield illumination or by staining with specific antitreponemal antibodies labeled with fluorescent dyes.

Question 2

What is a treponemal test?

Answer 2

use T. Pallidum as the antigen and detect specific anti-T. Pallidum antibodies.

Question 3

What is a nontreponemal test?

Answer 3

measure IgG and IgM antibodies developed against lipids released from damaged cells during the early stage of disease and present on the cell surface of treponemes. • The big difference is that nontreponemal tests are less sensitive than treponemal tests for average healthy people in primary and tertiary phase, but treponemal tests are unreliable in patients with AIDS, because they have a weak immune system.

Question 4

B. recurrentis- diseases

Answer 4

Epidemic Relapsing Fever

Question 5

B. recurrentis- clinical Sx

Answer 5

Recurrent episodes of fever and septicemia seperated by afebrile periods.

Question 6

B. recurrintis- lab tests

Answer 6

Microscopy

Question 7

B. recurrentis- epidemiology

Answer 7

Transmitted person to person with lice as the vector. Seen most commonly in crowded or unsanitary conditions (refugee camps)

Question 8

B. recurrentis- pathogenesis

Answer 8

Antigenic Variation - change proteins on outer surface so that antibodies don’t recognize them. This causes relapses of infection.

Question 9

B. burgdorferi- diseases

Answer 9

Lyme Borreliosis

Question 10

B. burgorferi- clinical Sx

Answer 10

3 Stages: 1. Bulls Eye rash and flu like symptoms for 2-3 weeks. 2. Disseminated fatigue, migratory joint and muscle pain. 3. Chronic arthritis and encephalitis

Question 11

B. burgdorferi- lab tests

Answer 11

Immunofluorescence and western blot

Question 12

B. burgdorferi- epidemiology

Answer 12

Mainly in the northeastern US. The reservoir is deer and mice, and the vector is a tick. Tick bites deer, the bites human.

Question 13

T. pallidum- diseases

Answer 13

Venereal Syphilis

Question 14

T. pallidum- clinical Sx

Answer 14

3 Phases: Primary Phase - lesions (chancres) at site of infection and infiltration of PMNs and macrophages. Secondary Phase - prominent skin lesions dispersed over the entire body surface. Late Phase (Tertiary) - all tissues may be involved.

Question 15

T. pallidum- lab tests

Answer 15

DFA microscopy if mucosal ulcers are observed. Serology is sensitive.

Question 16

T. pallidum- epidemiology

Answer 16

Humans are the only host and its transmitted by sexual contact. Congenital Trasmission - during the first 8 years, if untreated, trasmission from mother to fetus can occur at any time

Question 17

T. pallidum-pathogenesis

Answer 17

Lack species specific antigens on cell surface, so they are able to avoid the immune system. They resist phagocytosis, and are able to bid to fibronectin allowing direct interaction with host tissues.

Question 18

T, carateum- disease

Answer 18

Pinta

Question 19

T. carateum- clinical Sx

Answer 19

Small papules develop on the skin and persist for months to years before resolving

Question 20

Leptospira- disease

Answer 20

Leptospirosis

Question 21

Leptospira- clinical Sx

Answer 21

Most common form of disease is mild and has virus like symptoms. Systemic leptospirosis most commonly presents as aseptic meningitis. Most serious is Weil Syndrome is characterized by vascular callapse, thrombocytopenia, hemorrhage and hepatic and renal dysfunction

Question 22

Leptospira- lab tests

Answer 22

Culture blood or CSF in the first 7-10 days of illness

Question 23

Leptospira- epidemiology

Answer 23

Reservoirs are rodents, dogs, farm animals and wild animals with humans as the end-stage host. People are infected through exposure to water contaminated with urine from an infected animal or handling tissues from an infected animal. Disease is more common during warm months.