Trichinellosis

Question 1

True or false: Trichinella is the smallest nematode parasite in humans

Answer 1

True

Question 2

What is the source of Trichinella?

Answer 2

Food-borne

Question 3

What species has domestic pigs and wild mammals as major hosts?

Answer 3

T. spiralis

Question 4

What species has bears and walruses as major hosts?

Answer 4

T. nativa

Question 5

Which species has wild mammals and birds as major hosts?

Answer 5

T. pseudospiralis

Question 6

Which Trichinella species are non-encapsulated?

Answer 6

T. pseudospiralis, T. papuae, T. zimbabwensis

Question 7

What is the reservoir of T. spiralis?

Answer 7

Pigs

Question 8

What is the reservoir of T. nativa?

Answer 8

Polar bears, walruses

Question 9

What is the reservoir of T. pseudospiralis?

Answer 9

Pigs

Question 10

What is the distribution of T. spiralis?

Answer 10

Worldwide

Question 11

What is the distribution of T. nativa?

Answer 11

Arctic

Question 12

What is the distribution of T. pseudospiralis?

Answer 12

Worldwide

Question 13

What is the distribution of T. nelsoni?

Answer 13

Africa

Question 14

What is the distribution of T. britovi?

Answer 14

Temperate zone

Question 15

Associate the following characteristics with the Trichinella species
a. High reproductive capacity, no freezing resistance
b. Low reproductive capacity, freezing resistance
c. Low reproductive capacity, no freezing resistance, no capsule
d. Low reproductive capacity, no freezing resistance

Answer 15

a. T. spiralis
b. T. nativa and T. britovi
c. T. pseudospiralis
d. T. nelsoni

Question 16

What makes Trichinella’s life cycle unique?

Answer 16

Its intracellular localization in enterocytes and skeletal striated muscle cells

Question 17

True or false: All stages in the life cycle of Trichinella occur in the same host

Answer 17

True

Question 18

What is the life cycle of T. spiralis?

Answer 18

Humans infected via uncooked, contaminated meat and animals infected from eating contaminated meat
Juveniles carried by hepatoportal system through liver, heart and lungs into muscle
They grow to sexual maturity
Male and female worms copulate to produce juveniles
Juvenile worms migrate into muscle of host and mature into infective stage

Question 19

In which ways is Trichinella like a virus?
a. They penetrate individual fibers
b. They alter the gene expression of the host cell
c. They subvert and redirect the host cell activities to their survival
d. All of the above

Answer 19

d

Question 20

How many molts do Trichinella larvae undergo in a period of 30 hours?

Answer 20

4

Question 21

True or false: The adult male worm is bigger than the adult female worm

Answer 21

False, the female worm is bigger than the male worm

Question 22

Place the following steps leading to encystation in order
a. Fiber loses its myofilaments
b. Fiber smooth endoplasmic reticulum increases
c. Fiber mitochondria degenerates
d. Fiber nuclei enlarge
e. Larvae enter the muscle fiber cell
f. Encapsulation of the unit with collagen secreted by neighboring fibroblasts

Answer 22

e, a, d, b, c, f

Question 23

What is the stichosome?

Answer 23

Row of discoid cells containing secretory granules

Question 24

What is the action of stichocytes?

Answer 24

Secrete antigens into nurse-cell parasite complex and mediate alteration of host gene expression

Question 25

What are the most invaded muscles?

Answer 25

Eye, tongue, masticatory muscles, diaphragm, intercostals, arms, legs

Question 26

True or false: Nurse cells form in the heart muscle cells

Answer 26

False

Question 27

True or false: Nurse cells do not encyst in smooth muscle

Answer 27

True

Question 28

True or false: Nurse cells form in the nervous system

Answer 28

False, they do not

Question 29

What is associated with the invasion of muscles?

Answer 29

Intense inflammatory reaction

Question 30

What condition develops 14 days after penetration of the muscle cell?

Answer 30

Edema

Question 31

What is the reaction that triggers the inflammatory reaction?

Answer 31

Release of secretory-excretory antigens

Question 32

Place the following with their category of resistance to infections a. Natural resistance to infection b. Resistance acquired after a first contact with the same infectious agent c. Resistance acquired after a first contact with an unrelated infectious agent or immunogenic substance

Answer 32

a. Innate b. Specified acquired immunity c. Non-specific acquired immunity

Question 33

A first infection with which disease protects against Trichinellosis?

Answer 33

Mycobacterium tuberculosis

Question 34

Mice infected with which parasite are protected against Trichinellosis?

Answer 34

Toxoplasma

Question 35

True or false: Th1 and Th2 immune responses play a role in trichinellosis

Answer 35

True

Question 36

What other immune responses are involved in resistance?

Answer 36

Serum antibodies, T cells and ADCC

Question 37

Which immune cell is important in the response to nematode?

Answer 37

Eosinophils

Question 38

What controls eosinophil levels?

Answer 38

T cells

Question 39

True or false: Activation of Th1 cells produces a high amount of IL-5

Answer 39

False, activation of Th2 cells produces a high amount of IL-5

Question 40

What is the pathology of the intestinal stage?

Answer 40

Traumatic damage to the tissues leading to inflammation, nausea, vomiting, sweating and diarrhea

Question 41

What is the pathology of the migrating larvae?

Answer 41

Damage to blood vessels leading to edema

Question 42

What is the pathology of the formation of nurse cells?

Answer 42

Muscle pain, eosinophilia and edema in tissues

Question 43

Fever, orbital edema, myalgia and eosinophilia are features of which type of trichinellosis?

Answer 43

Acute trichinellosis

Question 44

What is another frequent sign of acute trichinellosis?

Answer 44

Splinter hemorrhages in nail bed

Question 45

What is the diagnosis of trichinellosis?

Answer 45

Detection of muscle nurse cell by biopsy or PCR in epidemiological studies

Question 46

What is the treatment for trichinellosis?

Answer 46

Analgesics and immunosuppressive drugs like prednisone to relieve symptoms and corticosteroids to reduce inflammation