(P2) Inf. Dis: Trichinellosis (the skeletal muscle) (222)

Question 1

name this slide

1. Name the tubular parallel structures:
2. Name the coiled up object:
3. Name the white structure surrounding

the coiled object:

Answer 1

Trichinellosis (the skeletal muscle) (222)

1. striated muscle
2. larvae
3. optically empty cleft around larvae

Question 2

name this slide

What is the entire structure encapsulating the object called and what is it responsible for ?

Answer 2

Trichinellosis (the skeletal muscle) (222)

Nurse Cell

The parasite has evolved a way of stimulating blood vessel development around the cell, in order to receive the nutrients it needs.

In trichinosis, nurse cells are invariably skeletal muscle cells; these are the only type of cell that can support the parasite.

Question 3

name this slide

Name the center structure filled with 6 small round/large cells:

Answer 3

Trichinellosis (the skeletal muscle) (222)

New vessels

Question 4

Trichinellosis (the skeletal muscle) (222)

1. What organism causes this infection?
2. Route of transmission?

Answer 4

1. trichinella spiralis (nematode parasite)
2. ingestion of undercooked meat from its or venison

Question 5

Trichinellosis (the skeletal muscle) (222)

Where does this infection occur in the body?

Answer 5

places with vascularized muscle tissue:

diaphragm, myocardium, intercostal muscles

Question 6

Trichinellosis (the skeletal muscle) (222)

1. Characteristic change in host cell to…?
2. Clinical symptoms?

Answer 6

1. nurse cells gain collagenous capsule and develop new vessels around it

2. myalgias, fever, dyspnea

Question 7

Trichinellosis (the skeletal muscle) (222)

What is the causative agent:

Answer 7

Trichanella spiralis (parasite/nematode)

Question 8

Trichinellosis (the skeletal muscle) (222)

Pathogenesis:

Answer 8

Acquired through the ingestion of larvae in undercooked meat from pigs that have themselves been infected by eating meat infected by T. spiralis.

Question 9

Life Cycle:

Answer 9

In striated skeletal muscle larvae become intracellular parasites, increase dramatically in size and modify the host muscle cells (nurse cells) so that it loses its stratification, gains a collagenous capsule and develops a plexus of new blood vessels around itself.

Question 10

Trichinellosis (the skeletal muscle) (222)

Clinical Manifestations?

Answer 10

• Fever, myalgias, marked eosinophilia and periorbital edema.*
• In some cases, dyspnea, encephalitis and cardiac failure*

Question 11

Trichinellosis (the skeletal muscle) (222)

Morphology:

Cysts in the Striated skeletal muscle: explain

Answer 11

Cysts form in striated skeletal muscle characterized by coiled larvae surrounded by membrane bound vacuoles in myocytes, which is itself surrounded by eosinophilic infiltrate.

Question 12

Trichinellosis (the skeletal muscle)

Morphology:

Heart and Lungs

Answer 12

In the heart there is patchy interstitial myocarditis characterized by eosinophils and giant cells à may lead to scarring.

In the lungs larvae cause focal edema and hemorrhages.

Question 13

Trichinellosis (the skeletal muscle)

Morphology:

CNS

Answer 13

In the CNS larvae cause diffuse lymphocytic and eosinophilic infiltrate with focal gliosis within s. capillaries of the brain.

Scarring is characteristic of T. spiralis.

Question 14

Trichinellosis (the skeletal muscle)

Pathology:

Answer 14

Intestinal lesions

Larva in striated muscles

Question 15

Trichinellosis (the skeletal muscle)

How are muscles affected?

Answer 15

Muscles:

Nuclei # and size increase

Question 16

Trichinellosis (the skeletal muscle)

Name the 2 clinical phases:

Answer 16

The two main phases for the infection:

1. enteral (affecting the intestines)
2. parenteral (outside the intestines).

The symptoms vary depending on the phase, species of Trichinella, quantity of encysted larvae ingested, age, sex, and host immunity.

Question 17

name this slide

1. What are the granular purple looking cells called?
2. What is the light purple stucture next to the Muscle cells called?
3. what is the pail looking structure surrounding the Larva

Answer 17

Trichinellosis (the skeletal muscle)

1. Inflammaroty cells ( eosinophils respond to the parasite infiltration)
2. Muscle fiber degeneration
3. Nurse cells (pale)