Animals are a more direct threat to humans with this nematode than with the other larva migrans because the eggs of Strongyloides are embryonated and can be infective as soon as they're passed. They do not require a prolonged period of development in the soil!

Disease in humans:

People are infected by cutaneous penetration of infective larvae. The larvae then migrate to the gastrointestinal tract. Clinical symptoms of GI tract invasion include:

• abdominal pain and nausea
• diarrhea
• protein-losing enteropathy and weight loss
• eosinophilia
• urticarial rash perianally (may extend to the buttocks, abdomen and thighs)

The most severe disease occurs in immunocompromised patients due to "hyperinfection" or "autoinfection" i.e., infective larvae reinfect the person via the perineum or via the lower GI tract before they've even exited the body.

• In these patients, the infestation may be fatal.
  • In addition to gastrointestinal symptoms, there may also be evidence of pulmonary infiltration (due to larval migration in the lungs) and secondary gram (-) sepsis or meningitis.

Disease in dogs:

The larvae of Strongyloides stercoralis burrow into the mucosa of the small intestine, causing enteritis, which is sometimes hemorrhagic.

• Clinical disease is most commonly seen in young puppies.

Diagnosis of Strongyloides infection in dogs:

• detection of larvae on fecal floatations (Sheather's sugar or zinc sulfate)
• detection of larvae in direct fecal smears

Treatment of Strongyloides infection in dogs:

• ivermectin (treatment of choice)
• thiabendazole, mebendazole

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