Parasitic infections of blood and tissues

Question 1

What is the pathogenesis of african sleeping sickness?

Answer 1

1. Flagellated protozoa develops in gut of tsetse fly 2. Chancre / hard nodule at site of bite 3. Parasite replicates in blood and lymphatics and goes to CNS

Question 2

What is the causative agent of Chaga’s disease?

Answer 2

Trypanosoma cruzi

Question 3

What is the causative agent of African sleeping sickness?

Answer 3

Trypanosoma brucei

Question 4

What are the symptoms of Chaga’s disease?

Answer 4

1. Development of chagoma (Romana’s sign) 2. Fever, malaise, myalgia, hepatosplenomegaly 3. Asymptomatic for life, or chronic (cardiac and GI)

Question 5

What is the diagnosis for Chaga’s disease?

Answer 5

1. Travel history 2. Acute - detection in peripheral blood 3. Chronic - serology

Question 6

How is Leishmaniasis transmitted?

Answer 6

Bite of sand fly - parasites are regurgitated into blood stream

Question 7

What are the reservoirs for leishmaniasis?

Answer 7

Dogs and rodents

Question 8

What are the leishmaniasis spp. responsible for cutaneous presentations?

Answer 8

L. major, L. tropica, L. mexicana

Question 9

What are the leishmaniasis spp. responsible for mucocutaneous presentations?

Answer 9

L. braziliensis

Question 10

What are the leishmaniasis spp. responsible for visceral presentations?

Answer 10

L. donovani, L. infantum, L. chagasi

Question 11

What is the initial presentation for visceral leishmaniasis?

Answer 11

Persistent low grade fever

Question 12

Resolution of leishmaniasis is dependent on what type of immunity?

Answer 12

Cell mediated immunity (gamma interferon mediated activation of macrophages)

Question 13

What are the main malaria-causing species of plasmodium?

Answer 13

P. falciparum and P. vivax

Question 14

What is the characteristic clinical feature of malaria?

Answer 14

Malarial paroxysm

Question 15

What are the durations and patterns of paroxysm for malarial species?

Answer 15

1. P. vivax and P. ovale - 48 hrs 2. P. malariae - 72 hrs 3. P. falciparum - 48 hrs

Question 16

How does anemia occur in malaria?

Answer 16

Asexual stage of parasite destroys RBCs each time it completes a cycle of replication

Question 17

What are the three mechanisms involved in the pathogenesis of malaria?

Answer 17

1. RBC lysis by mature asexual intra-erythrocytic parasites 2. Suppression of erythropoiesis by cytokines (TNFa, IL-1) 3. Destruction of RBCs by the spleen

Question 18

Severe anemia is seen in which species of plasmodium?

Answer 18

P. falciparum - highest parasitemia

Question 19

What are other symptoms / complications of malaria?

Answer 19

Splenomegaly, hypoglycemia, lactic acidosis, microvascular sequestration

Question 20

Which populations are most at risk for babesiosis infection?

Answer 20

Elderly, asplenic, immunosuppressed

Question 21

The Maltese Cross morphology is indicative of what disease?

Answer 21

Babesiosis (Babesia spp.)

Question 22

What is the treatment for babesiosis?

Answer 22

Atovaquone and azithromycin (quinine / clindamycin)

Question 23

How is babesiosis transmitted?

Answer 23

Bite of tick

Question 24

What are the causative agents of filariasis?

Answer 24

Filarial nematodes Wuchereria bancrofti and Brugia malayi

Question 25

What is the vector for filariasis?

Answer 25

Mosquito

Question 26

How is schistosomiasis transmitted?

Answer 26

1. Egg get into water via urine or feces 2. Eggs hatch, infect snails, release cercariae which penetrate human skin and circulate to intestine, liver or bladder

Question 27

What are the symptoms of S. japonicum / S. mansoni infection?

Answer 27

Chronic intestinal and hepatic dysfunction - portal fibrosis and hypertension

Question 28

What are the symptoms of S. haematobium infection?

Answer 28

Hematuria, dysuria, urinary frequency, loss of bladder function, increased occurrence of squamous cell carcinoma of bladder