My answers to the CDC DPDx Monthly Case Studies for February - 2017 (437 and 438)

Case 437

A 31-year-old female, with travel to Mexico a few months prior, noticed a small worm-like object on the inner surface of her lower lip.  She removed the object with a needle and delivered it to her health care provider.  The object was forwarded to the CDC DPDx Team for identification.  Figures A and B were taken with a dissecting microscope and the ruler in the background shows one centimeter; Figure C is a composite of two images of the organism that was submitted taken with a compound microscope to show the entire organism at 40x magnification.

The insert (of the anterior end) was taken at 100x magnification.  What is your diagnosis?  Based on what criteria?

  Acknowledgements: This case was kindly provided by Optimus Medical Clinic, Houston, Texas.

 

Answer: Gongylonemiasis is the affliction caused by this parasite, which is simply protracted discomfort or sensation of movement in the buccal, oral or gingival areas associated with a sensation of foreign body.

 

Subjects commonly pull worms from their gums, tongue, lips, and inner cheeks after days and even weeks of reported discomfort.



Gongylonema pulchrum is the only parasite of the genus Gongylonema capable of infecting humans. Transmission to humans is due mostly to accidental ingestion of infected coprophagous insects contaminating  food  if unsanitary conditions pervade in its production chain.

The infection usually occurs when someone drinks contaminated water, or consumes an infected beetle.

In humans, there can be an up to six week incubation period for worm development and symptoms may not appear until the second molting of the worm, in which the young adult worms begin migration from the esophagus to the buccal and oral palate tissue. It is this movement through the mucosa of the mouth and lips that causes patients to complain of symptoms. The buccal mucosa with non-keratinized stratified squamous epithelium is the ideal environment for the parasite such as the mucous membrane of the inside of the cheek  contiguous with the mucosae of the soft palate, the undersurface of the tongue and the floor of the mouth.

The average length for male worms is 29.1 mm (1.15 in), while the average length for adult females is 58.7 mm (2.31 in).

The anterior end is covered by numerous cuticular platelets and the buccal opening is small.

Case 438

Fig. A

A 36-year-old male immigrant, with an elevated eosinophil count, was suspected of being infected with pinworms and was administered a pinworm paddle test.  Figures A-B show what was observed on the plastic paddle.  What is your diagnosis?  Based on what criteria?

Acknowledgments: This case and images were kindly provided by the Cadham Provincial Public Health Laboratory, University of Manitoba, Winnipeg, Canada.



Answer: Taeniasis occurs everywhere whenever raw or uncooked beef and/or pork meat infected with encysted  larval stage  are eaten.

Fig. B

Increased eosinophils may be a sign of infection.

Diagnosis of taeniasis is done mainly using stool sample, particularly by identifying the eggs. However, this has limitation at the species level because tapeworms basically have similar eggs.

One possible laboratory diagnostic method is the cellophane-tape technique or a paddle test.

 

 

P. Laranjeira (26/02/2017)