Deck 51: Tissue Nematodes Roundworms

Question 1

Humans acquire infection with Trichinella tissue nematode by ingesting undercooked meat that contains the infective encysted larvae.In which tissue do these larvae encyst?

A) Brain
B) Meninges
C) Myocardium
D) Striated muscle

Answer 1

D
The encysted larvae of the organism Trichinella spp.are ingested.When the undercooked meat is digested in the stomach, the larvae are resistant to the gastric pH and pass to the intestine, where they invade the mucosa.Trichinosis is a disease of the muscle caused by infection with the encysted larvae.

Question 2

MATCHING
Match the organism with the mode of transmission.
a.Dracunculus medinensis
b.Parastrongylus cantonensis
c.Trichinella spp.
d.Parastrongylus costaricensis
Swine

Answer 2

A

Question 3

A definitive diagnosis can be made in a Trichinella infection on the basis of which of the following findings?

A) Presence of adult worms in the feces
B) Identification of encysted larvae through muscle biopsy
C) Presence of cutaneous larvae migrans in the skin
D) Identification of unembryonated eggs in the feces

Answer 3

B
Diagnosis may be difficult because the symptoms may resemble a variety of influenza-like illnesses.A thorough patient history is required to assist the physician in diagnosing the condition in a timely fashion.The identification of the encysted larvae through muscle biopsy provides a definitive diagnosis.However, based on the locations of the larvae, some tissues may be difficult to access; therefore the condition may not be diagnosed until the postmortem examination.

Question 4

MATCHING
Match the organism with the mode of transmission.
a.Dracunculus medinensis
b.Parastrongylus cantonensis
c.Trichinella spp.
d.Parastrongylus costaricensis
Crabs

Question 5

MATCHING
Match the organism with the mode of transmission.
a.Dracunculus medinensis
b.Parastrongylus cantonensis
c.Trichinella spp.
d.Parastrongylus costaricensis
Snails

Question 6

A child is believed to have a Toxocara cati infection in his eye, which he acquired after playing with a stray cat for several weeks.A serum titer was performed, which revealed a titer of 1:8.This laboratory value can be interpreted as:

A) normal.
B) insignificant.
C) diagnostic.
D) negative.

Question 7

Systemic involvement is rare in infection caused by Ancylostoma braziliense or A.caninum; however, pneumonitis may occur.The antihelminthic therapy used to treat this infection is:

A) ivermectin or thiabendazole.
B) metronidazole or thiabendazole.
C) mebendazole or ivermectin.
D) albendazole or diethylcarbamazine.

Question 8

MATCHING
Match the organism with the mode of transmission.
a.Dracunculus medinensis
b.Parastrongylus cantonensis
c.Trichinella spp.
d.Parastrongylus costaricensis
Copepods