Parasitology part 2

Question 1

Describe the trematodes.

Answer 1

Oval leaf shaped; Ventral sucker. Mostly hermaphrodites (Schistosomiasis)

Question 2

How is Schistosomiasis transmitted?

Answer 2

Direct penetration. Intermediate in snail. Found in freshwater snails and human waste

Question 3

Discuss Schistosomiasis pathology.

Answer 3

1. Initail dermatitis when cercariae attach.
2. Intense inflammation in submucosal venules of intestine or urinary bladder.
3. Eggs released into bladder to complete life cycle or into bloodstream to end up in liver where it forms granulomas.

Question 4

Discuss Schistosomiasis clinical presentation.

Answer 4

Inital pruritis, then bloody diarrhea, finally hepatomegaly , ascites and bladder cancer.

Question 5

How is Schistosomiasis diagnosed?

Answer 5

Eggs in stool or urine; Treat with Praziquantel after 3 months of exposure

Question 6

Describe protozoa

Answer 6

Unicellular; motile

Question 7

How is Trypanosoma cruzi transmitted? (Chagas Disease)

Answer 7

Direct penetration; Kissing bug. Defecation at time of blood meal. Subsequent scratching leads to inoculation

Question 8

Discuss Trypanosoma cruzi pathophysiology.

Answer 8

1. Initial chagoma at site of bite

2. Chronic infection by amastigotes; Targets cardiac muscle, esophagus and colon

Question 9

Describe Typanosoma cruzi clinical presentation.

Answer 9

Cardiac: Rhythm disturbances, cardiomyopathy
Colon: Constipation, Abdominal pain
Esophagus: Difficulty or painful swallowing, chest pain

Question 10

How is Trypanosoma cruzi (Chagas Disease) diagnosed?

Answer 10

Parasite specific antibodies; Visual observation of motile parasite in unfixed blood smears.

Question 11

Describe Leishmania.

Answer 11

Arthropod; Promastigote form is injected from sand fly. Amastigote is in macrophages

Question 12

Discuss Leishmania pathophysiology

Answer 12

Amastigotes in macrophages cause protective Th1 (IFN-y) response. Th2 responses lead to progression/exacerbation. Injection of fly salivary proteins along with promastigote is crucial to disease progression.

Question 13

Discuss treatment of Leishmania.

Answer 13

Immune response to fly salivary proteins can block progression of disease; Novel vaccine strategy.

Question 14

Describe the clinical presentation of Leishmania

Answer 14

Itchiness at sight of bite; Can spread to oral and nasal mucosa. Chronic exposure leads to hepato/splenomegaly and skin lesions.

Question 15

Describe Toxoplasma gondii

Answer 15

Danger to immunocompromised patients; Transmitted by ingestion and causes cysts. Cysts come from cat feces or undercooked meat.

Question 16

Discuss Toxoplasma gondii pathophysiology

Answer 16

Can invade any cell type; Immunocompetent individuals can prevent cyst rupture.

Question 17

Describe toxoplasma gondii clinical presentation in Immunocompetent versus immunocompromised patients.

Answer 17

Immunocompetent: Fever, headache, fatigue.
Congenital: Spontaneous abortion, epilepsy, hearing loss
Immunocompromised: Seizure, encephalitis

Question 18

How is Toxoplasma gondii diagnosed?

Answer 18

Presence of antibodies, Fetal testing of amniotic fluid for antigen; Neonatal testing for IgM

Question 19

How are Trichomonas transmitted?

Answer 19

Sexually transmission; Pear shaped with five flagella

Question 20

Discuss Trichomonas pathophysiology.

Answer 20

Binds to columnar cells but DO NOT INVADE. Kills cell by direct contact. Reproduces by binary fission; No cyst. Recruits PMNs and macrophages

Question 21

How does Trichomonas present clinically?

Answer 21

Asymptomatic in males; Vaginal discharge in females.

Question 22

How is Trichomonas diagnosed?

Answer 22

Microscopic examination of wet mount motility; Large number of PMNs