The prevalence and response to therapy of Strongyloides stercoralis in patients with asthma from endemic areas.

STUDY OBJECTIVE: To evaluate the prevalence and response to therapy of Strongyloides stercoralis infection in immigrant patients with asthma from areas endemic for Strongyloides.

DESIGN AND INTERVENTIONS: In all patients, we performed a complete history and physical examination, complete blood cell counts (CBC), S stercoralis serologic tests, spirometry, and evaluated three stool samples for ova and parasites. Patients treated for S stercoralis infection had follow-up CBC, spirometry, serologic tests, and at least three additional stool examinations to confirm eradication of the parasite.

SETTING: Ambulatory and hospitalized patients who were referred to the respiratory medicine clinic of a general hospital for the evaluation and treatment of asthma.

PATIENTS: Forty-five asthmatic adults, representing 12 endemic countries, ranging in age from 20 to 76 years, were prospectively evaluated.

RESULTS: Six of 45 patients were infected with S stercoralis, which yielded a prevalence of 13 percent. The patients with asthma and S stercoralis infection had higher blood eosinophil counts (p = 0.006) and were younger (p = 0.006) compared with patients with only asthma. There was no difference in the duration of asthma, spirometry, or steroid use between the two groups. Patients with S stercoralis and asthma tended to be more recent immigrants (p = 0.05). Five of the six patients with S stercoralis agreed to be treated with thiabendazole but only four returned for follow-up evaluation. All four patients had eradication of S stercoralis infection confirmed by negative stool examinations and a decline in S stercoralis serology (160 +/- 25 percent vs 13 +/- 13 percent, p = 0.03). All four patients had a decline in total blood eosinophil counts (2,476 +/- 832 cells per cubic millimeter vs 551 +/- 138 cells per cubic millimeter, p = 0.03) without a clinical improvement in asthma.

CONCLUSIONS: Our data suggest that patients with asthma from areas endemic for S stercoralis, who have elevated peripheral blood eosinophil counts, should be screened for S stercoralis infection. Successful eradication of S stercoralis, however, may not result in a clinical improvement of asthma.