Introduction to Human Parasites: Protozoa and Helminths

Question 1

A parasite is ______.

Answer 1

an organism which lives upon or within another living organism at whose expense it obtains some advantage

Question 2

What are protozoa?

Answer 2

unicellular eukaryotes

Question 3

Metazoa are?

Answer 3

multicellular eukaryotes

Question 4

What are helminths?

Answer 4

worms

Question 5

What is an arthropod?

Answer 5

insect

Question 6

A _____ is an organism which lives upon or within another living organism at whose expense it obtains some advantage.

Answer 6

parasite

Question 7

What is the definitive host?

Answer 7

species in which the parasite undergoes sexual replication

Question 8

What are unicellular eukaryotes called?

Answer 8

protozoa

Question 9

The species in which asexual replication of the parasite occurs is called?

Answer 9

an intermediate host

Question 10

What are multicellular eukaryotes called?

Answer 10

metazoa

Question 11

What is an insect called?

Answer 11

arthropod

Question 12

What are worms called?

Answer 12

helminths

Question 13

The species in which the parasite undergoes sexual replication is called the ____.

Answer 13

definitive host

Question 14

What is an intermediate host?

Answer 14

species in which asexual replication of a parasite occurs

Question 15

What is tropism?

Answer 15

the ability to affect a certain tissue

Question 16

For parasitic diseases, diagnosis is often made by ____ of the parasites in specimens or biopsy materials collected directly from patients.

Answer 16

direct examination

Question 17

Name the 3 pathologic helminth groups in humans.

Answer 17

1. Roundworms/Nematodes
2. Flatworms/Trematodes/Flukes
3. Tapeworms/Cestodes

Question 18

The protozoan parasites in humans include ____, ____, ____, _____, and _____.

Answer 18

1. amebas
2. flagellates
3. ciliates
4. sporozoa
5. microsporidia

Question 19

Schistosomiasis features

Answer 19

1. transmitted via fresh water
2. intestinal or urinary manifestations
3. 2nd only to malaria in #
4. mostly sub-Saharan Africa
5. trematodes/flatworms
6. complex life cycle

Question 20

Describe the schistosome life cycle.

Answer 20

1. infected humans shed eggs in urine or feces
2. eggs in water release miracidia, which infect snails
3. mircidia grow into cercariae, which penetrate human skin
4. cercariae mature into worms w/I the human venous system, where they mate
5. eggs circulate blood and are released into intestines or bladder

Question 21

Cercariae invading the skin can cause ____ within 2-3 days.

Answer 21

dermatitis (swimmers itch)

Question 22

What is another name for the acute phase of schistosomiasis? When does it occur?

Answer 22

Katayama fever; 4-8 weeks post skin invasion

Question 23

In which body sites are granulomatous and fibrotic changes seen from schistosomiasis? Why?

Answer 23

the liver and/or bladder; from EOS infiltrating the inf. area

Question 24

What is the most important parasitic disease?

Answer 24

malaria

Question 25

What is the genus that causes Malaria in humans? Name the 4 species.

Answer 25

Plasmodium; 1. vivax 2. ovale 3. malariae 4.q falciparum

Question 26

Describe the malaria parasite life cycle.

Answer 26

1. infected mosquito bites human, injecting sporozoites into the blood 2. asexual phase of development (schizogony) occurs in liver 3. Next, merozoites are released into the blood to infect erythrocytes and undergo additional asexual replication *** sexual phase is completed in mosquito w/I salivary gland

Question 27

The symptoms of malaria are primarily associated with the _____ and release of merozoites.

Answer 27

rupture of infected erythrocytes

Question 28

What physical exam findings will be seen in a Malaria pts?

Answer 28

jaundice, hypotension, tachycardia, fever, hepatosplenomegaly

Question 29

What is the major cause of death in Malaria pts?

Answer 29

multi-organ failure

Question 30

With _____ infections, immune complex deposition | leading to glomerulonephritis is common.

Answer 30

P. malariae

Question 31

The diagnosis of malaria is usually established by detecting _____ in stained thick or thin blood films.

Answer 31

the asexual forms of the parasites

Question 32

_____--caused Malaria is widely distributed from | tropical to temperate zones, but _____ occurs primarily in the tropics and subtropics.

Answer 32

P. vivax; P. falciparum

Question 33

Name 4 diseases that confer resistance to Malaria but are otherwise bad news.

Answer 33

1. sickle cell anemia 2. thalassemias 3. G6PD deficiency 4. ovalocytosis

Question 34

Which allele is assoc. with recovery from falciparum malaria?

Answer 34

HLA-B53

Question 35

With P. malariae infections, _____ leading to glomerulonephritis is common.

Answer 35

immune complex deposition

Question 36

What is ascites?

Answer 36

fluid that distends the abdomen

Question 37

What are some RBC changes seen in F. malaria infected cells?

Answer 37

membrane protrubances (knobs) containing PfEMP1 adhesive protein, which allow attachment to BVs and other RBCs

Question 38

Acquired immunity against malaria prevents ____ but does not ____.

Answer 38

high-level disease; prevent infection

Question 39

Malarial immunity declines when ____.

Answer 39

pt lives outside of an endemic area for an extended period of time