Prevalence of Strongyloides stercoralis in an urban US AIDS cohort

Abstract

Objectives: We examined the prevalence of Strongyloides stercoralis (Ss) infection in a cohort of AIDS patients from a US urban centre. We monitored our cohort for possible cases of dissemination or immune reconstitution inflammatory syndrome after antiretroviral therapy (ART) initiation.

Methods: One hundred and three HIV-infected participants were prospectively sampled from a cohort observational study of ART-naive HIV-1-infected patients with CD4 ≤100 T cells/μl. Clinical symptoms, corticosteroid therapy, eosinophilia, CD4 count, and plasma HIV-RNA were reviewed. Sera were tested by an enzyme-linked immunosorbent assay (CrAg-ELISA) to crude Ss extract or to an Ss-specific recombinant protein (NIE) and by luciferase immunoprecipitation system assay (LIPS) for Ss-specific antibodies.

Results: Twenty-five per cent of study participants were Strongyloides seropositive by CrAg-ELISA and 62% had emigrated from Strongyloides-endemic areas. The remaining 38% of the seropositives were US born and tested negative by NIE and LIPS. CrAg-ELISA-positive participants had a median CD4 count of 22 T cells/μl and a median HIV-RNA of 4·87 log(10) copies/ml. They presented with diarrhea (27%), abdominal pain (23%), and skin manifestations (35%) that did not differ from seronegative patients. Peripheral blood eosinophilia was common among seropositive patients (prevalence of 62% compared to 29% in seronegatives, P = 0·004). Seropositive patients were treated with ivermectin. There were no cases of hyperinfection syndrome.

Discussion: Strongyloidiasis may be prevalent in AIDS patients in the USA who emigrated from Ss-endemic countries, but serology can be inconclusive, suggesting that empiric ivermectin therapy is a reasonable approach in AIDS patients originating from Strongyloides endemic areas.

Figure 1

Comparison of eosinophil count between Strongyloides CrAg-ELISA-seropositive and -seronegative participants pre-antiretroviral therapy (pre-ART). Number of eosinophils (A) was assessed from 103 patients at their baseline visit (pre-ART). Significance determined by Mann–Whitney U test. Open shapes indicate patients on corticosteroid therapy at the time of blood sampling. When patients on corticosteroid therapy were excluded from the analysis, there was a statistically significant difference in eosinophil count (P = 0.02). (B) Absolute eosinophil counts from 16 Strongyloides CrAg-ELISA-positive patients treated with ivermectin with longitudinal follow-up for 24 weeks after ivermectin administration. WK 0 indicates treatment with a standard dose of ivermectin (200 μg/kg for 1–2 days). Grey lines denote the range of normal absolute eosinophil counts (0.04–0.54 K/μl for males and 0.04–0.36 K/μl for females).