Parasite-specific IgG response and peripheral blood eosinophil count following albendazole treatment for presumed chronic strongyloidiasis.

BACKGROUND

In developed countries, asymptomatic chronic Strongyloides stercoralis infection occurs in immigrants from endemic regions of the world. Accurate and reliable means of diagnosis and follow-up are required for effective management. The role of S stercoralis enzyme-linked immunosorbent assay (ELISA) in this context was examined.

METHODS

In this study, 95 asymptomatic Laotian immigrants living in Melbourne, Australia, for an average of 12 years, were screened for S stercoralis infection using stool microscopy, eosinophil count, and serology by ELISA. Twenty-two patients with a positive ELISA were treated with albendazole, 400 mg twice daily for 3 days, and monitored with serology, fecal microscopy, and eosinophil counts at 2, 6, 12, and 36 months after treatment.

RESULTS

Patients with moderately reactive baseline ELISA and no eosinophilia had no significant change in either measure over the 36 months of follow-up. All patients with a strongly reactive baseline ELISA showed a reduction in reactivity over the first 6 months of treatment. However, in 50% of these patients, reactivity increased between 12 and 36 months, suggesting treatment failure and relapse of infection. One patient had confirmed treatment failure based on the development of hyperinfection syndrome.

CONCLUSION

The results support evidence that serology is a valuable tool in monitoring treatment responses in patients with suspected strongyloidiasis and highlights the need to ensure that S stercoralis is completely eradicated after treatment.