Infectious Disease Compendium

Strongyloides

Microbiology

A nematode. Many animals have their own, with Strongyloides stercoralis being the main human species. S. fuelleborni in central Africa and S. kellyi in Papua New Guinea can infect humans.

Epidemiologic Risks

Walking barefoot in human stool. It is found throughout the third and developing world, including Kentucky (PubMed) and the US South.

Dogs may be a source (PubMed).

HIV likely a risk as well.

Syndromes

Local irritation/itching where you stepped, gi upset.

It is a small bowel pathogen.

With steroids or hematologic malignancy, the organism can disseminate with a hyper-infection syndrome (PubMed)  from the bowel to everywhere and anywhere, often accompanied with poly-microbial bacteremia from the bowel (PubMed), hyper-eosinophilia and 2/3 will die (PubMed). They can get the thumbprint sign of the skin: the organism goes up the umbilical veins to the skin and cause a hemorrhagic rash. Larva currens due to the rapid migration of the larvae through the skin. Larva currens is a red line that moves rapidly (more than 5 cm or 2 inches a day), and then disappears.

It can cause disease both from reactivation and be acquired from the transplanted organ (PubMed).

People from endemic areas should be screened before immunosuppression, but most will not think of the disease.

And, for an off the wall cause of recurrent meningitis, chronic strongyloidiasis with human T­-lymphotropic virus type 1 (PubMed).

Treatment

Ivermectin 200 micrograms /kg for 2d is probably the treatment of choice; transplant patients may require longer courses of therapy (PubMed).

And one test of cure study suggests ivermectin does not cure any patient with the standard treatment plans (PubMed) with all patients remaining PCR positive and most remaining stool positive. So how long should patients get therapy?

Thiabendazole 25 mg/kg bid for 2 days (maximum of 3 g/day). Albendazole 200 mg/kg/day for 1 to 2 days. In the hyper infection syndrome treatment for 2 to 3 weeks.

Also 7-day course of oral albendazole 800 mg daily is INFERIOR to Ivermectin single dose (200 microgram/kilogram body weight), or double doses, given 2 weeks apart, in Thai patients with chronic strongyloidiasis (PubMed).

Notes

There is a case of one person manifesting 75 years (seventy five, so you know it is not a typo) after leaving an endemic area (PubMed). This is because the unusal ability to cause autoinfection: the larvae penetrate the wall of the bowel or the skin of the perineum, enters the circulation, travels to the lungs, and then back home to the small intestine. Most other parasites have to leave the human for a while to finish reproducing.

In the UK it is called threadworm.

Last Update: 05/15/18.