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.