Management of Strongyloidiasis

• Spontaneous cure cannot be expected, due to the parasite’s unique autoinfection life cycle.
• Treat all patients with strongyloidiasis, even when asymptomatic, because of the risk of hyperinfection—a potentially fatal complication.
• Reliable diagnosis of patients at risk is needed for accurate recognition and treatment before immunosuppressive therapy is initiated, or in patients with HTLV-I or human immunodeficiency virus (HIV) infection.
• If emergency immunosuppression is required in a patient who may have previously undiagnosed strongyloidiasis, and diagnostic tests are not rapidly available (very few hospitals can do same-day serology), presumptive treatment with ivermectin should be considered.
• Cure can be achieved with single-dose ivermectin.
• Failure of treatment with ivermectin is generally due to the impairment of host immunity (frequent in patients with HTLV-I infection)

The treatment of strongyloidiasis is difficult because in contrast to other helminth infections, the Strongyloides worm burden has to be eradicated completely.

• Complete eradication is difficult to ascertain, because of the low worm load and irregular larval output.
• A definitive cure cannot be established on the basis of a negative follow-up stool examination alone—it also requires a decline in both serological titers and eosinophilia.
• A single stool analysis for strongyloidiasis was found to be negative in up to 70% of known cases of Strongyloides infection. Reliable testing requires multiple stool examinations, probably at least three and with suitable techniques.
• In the tropics, follow-up is a problem and if only fecal testing is available, it becomes the method of choice.
• Albendazole (400 mg b.i.d. for 3 days) is sometimes used as an alternative or compromise. However, the efficacy of albendazole in the treatment of strongyloidiasis has been shown to be very low in comparison with ivermectin, and it should therefore not be used unless there is no alternative.

Infection is prevented by avoiding direct skin contact with soil containing infective larvae. People at risk, especially children, should wear footwear when walking on areas with infected soil. Patients at risk should be identified and appropriate diagnostic tests should be performed before they begin immunosuppressive therapy.

Persons in household contact with patients are not at risk for infection. The proper disposal of human excreta reduces the prevalence of strongyloidiasis substantially.

No accepted prophylactic regimen exists and no vaccine is available.

Standard precautions should be observed for patients hospitalized with strongyloidiasis. Wearing gloves and gowns and diligent handwashing hygiene is important for those coming into potential contact with the patient’s feces .

• Early detection and effective treatment of S. stercoralis infection.
• Screening of patients who are at risk for chronic strongyloidiasis before immunosuppressive treatment is started, especially with corticosteroids.
• Preventive chemotherapy (PC) for S. stercoralis infection is not yet recommended by WHO, nor is it included in the strategy for soil-transmitted helminth control. However, consistent side benefits on S. stercoralis prevalence have been demonstrated after lymphatic filariasis and onchocerciasis elimination programs that used repeated PC with ivermectin/albendazole or with ivermectin alone.
• Proper evaluation of treatment using stool examination (with highly sensitive tests such as the Baermann technique, filter-paper culture, and agar-plate culture) and specific IgG serology follow-up for 1–2 years.
• Overseas presumptive treatment programs in refugee populations from countries where intestinal parasites are endemic (hookworm, Trichuris trichiura, Ascaris lumbricoides, and Strongyloides stercoralis).
• The installation and use of safe waste disposal systems still remains important.
• Wearing footwear could interrupt transmission of strongyloidiasis, but the cultural acceptability of footwear is low, particularly in hot climates, so other environmental control methods should be assessed. People who don’t have shoes often don’t have chairs, and then the buttocks are an additional target.
• Detect anthelmintic resistance at an early stage. Various in vivo and in vitro methods are available for assessing the efficacy of anthelmintics, and specific laboratory methods can be applied to confirm a suspicion of resistance in the field—e.g., as described in the World Association for the Advancement of Veterinary Parasitology (WAAVP) study recommendations and guidelines.