Microbiology Case Study: A 47 Year Old Male with Abdominal Pain and Diarrhea

A 47 year old male of Jamaican origin with no known past medical history presented to a clinic with abdominal pain and diarrhea. He has been working as a seasonal farmer and plans to return back to Jamaica by the end of the month. Stool samples were obtained and sent for culture and ova and parasite exam.

Rhabditiform larvae of Strongyloides stercoralis from the wet mount of O&P exam
Rhabditiform larvae of Strongyloides stercoralis from the wet mount of O&P exam
Blood agar plate demonstrating tracks made by crawling larvae
Blood agar plate demonstrating tracks made by crawling larvae

Strongyloides stercoralis is the primary species of the Strongyloides genus that causes human disease. The larvae are small and can reach around 1.5mm in length. The primary mode of infection is through contact with soil that is contaminated with larvae. The larvae are able to penetrate the skin and migrate through the body to the small intestine where they burrow and lay their eggs. The eggs hatch into larvae in the intestine, unlike other helminths. Of these larvae, most will be eliminated in feces, but some may shed and immediately re-infect the host. This is achieved either by burrowing into the intestinal wall, or by penetrating the perianal skin. The process is called auto-infection, and if the patient is not treated, they may continue to be infected throughout their life.

Strongyloides is generally found in warm and moist areas, as well as areas associated with agricultural activity. The majority of people infected with Strongyloides are asymptomatic, and those who do develop symptoms have generalized symptoms such as abdominal pain, bloating and diarrhea.

The time of exposure is usually unknown, although a local rash can occur at exposure. People exposed to Strongyloides can also develop a cough several days post exposure. Abdominal symptoms usually occur about 2 weeks later, and larvae can be found in the stool after 3-4 weeks. Strongyloides is treated with ivermectin as a first-line drug. Thiabendazole can also be effective.

 

-Mustafa Mohammed, MD is a 2nd year anatomic and clinical pathology resident at the University of Vermont Medical Center.

Wojewoda-small

-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Assistant Professor at the University of Vermont.

One thought on “Microbiology Case Study: A 47 Year Old Male with Abdominal Pain and Diarrhea”

  1. I have also diagnosed a rare case of this parasite in urine. This was not due to contamination.
    The patient actually presented with urine persistently stained with blood even when she was not menstruating. Her PCV came crashing and persisted for long. When I found the parasite in urine, I had to call for a repeat of sampling only to find same. I then made a wet preparation of her blood and found the parasite swimming everywhere. I saw about 30 parasites per field. We concluded that this was a case of deseminated Strongydiasis.

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