Question 1

Match the organism with the mode of transmission.
-Copepods

Accepted Answer

Copepods are the intermediate hosts of the parasitic worm Dracunculus medinensis, which is transmitted to humans when they drink water contaminated with copepods infected with the larvae of the worm.

Question 2

Match the organism with the mode of transmission.
-Crabs

Accepted Answer

Parastrongylus cantonensis, also known as the rat lungworm, is transmitted through ingestion of raw or undercooked snails, slugs, or crabs that are intermediate hosts.

Question 3

Match the organism with the mode of transmission.
-Snails

Accepted Answer

D

Question 4

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:

Accepted Answer

Serologic diagnosis has proven effective,particularly in ocular larval migrans (OLM).Aqueous humor elevated antibody titer specific for Toxocara spp. ,in comparison to serum levels,is considered diagnostic.Although serologic analysis can be useful,it is important to note that antibody titers may vary,depending on the location of the infection.A serum titer of 1:8 is considered significant for OLM;1:32 is significant for visceral (tissue)larval migrans (VLM).

Question 5

Match the organism with the mode of transmission.
-Swine

Accepted Answer

Trichinella spp. is transmitted through the consumption of undercooked pork or wild game, such as swine. The other organisms listed have different modes of transmission: Dracunculus medinensis is transmitted through ingesting water contaminated with copepods, Parastrongylus cantonensis is transmitted through ingesting raw snails or slugs, and Parastrongylus costaricensis is transmitted through ingesting raw or undercooked mollusks.

Question 6

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

Accepted Answer

A.braziliense or A.caninum is treated with ivermectin or thiabendazole.

Question 7

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

Accepted Answer

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 8

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

Accepted Answer

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.

Quiz 50: Tissue Nematodes

Match the organism with the mode of transmission. -Copepods

Match the organism with the mode of transmission. -Crabs

Match the organism with the mode of transmission. -Snails

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:

Match the organism with the mode of transmission. -Swine

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

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

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