Introduction Strongyloidiasis can persist and cause hyperinfection years after acquisition when host immunity is impaired. European Crohn's and Colitis Organisation guidelines1 on opportunisitc infections recommend that Inflammatory Bowel Disease (IBD) patients returning from endemic areas be screened. However, prevalence of intestinal helminths in migrant IBD patients is unknown. We investigated the sero-prevalence of Strongyloidiasis and factors associated with infection.
Methods Migrant patients attending IBD clinic over a 10-month period, with a diagnosis of Crohn's disease (CD) or Ulcerative colitis (UC), were tested for Strongyloides serology. Eosinophil count and inflammatory markers were measured. Ethnicity was used as a proxy for migrant status. Sero-positive patients were followed-up with a Strongyloides charcoal culture before treatment with Ivermectin. Repeat eosinophil count and inflammatory markers were performed 3 months later. T test and χ2 analysis (p<0.05) were performed using SPSS for Windows.
Results 97 migrant patients (54 CD vs 43 UC) were tested. 13/97 patients were sero-positive. In both groups, over 70% of patients were from Asia. Mean eosinophil counts (×109/l) were not different between the two groups (0.29 vs 0.22, p>0.05). No significant change was seen in eosinophil count or in inflammatory markers post treatment. In the sero-positive group 23% had past and current eosinophilia, but this was not statistically different from sero-negative patients. 9/13 reportable charcoal stool cultures were negative. No patients with Strongyloides were taking steroids, compared to 23% of sero-negative patients. In both groups, >40% were on two or more immunosuppressants.
Conclusion There is a high sero-prevalence of Strongyloides in migrant IBD patients. Patients from Asia demonstrated the highest prevalence. Eosinophilia and raised inflammatory markers were not predictive of positive serology, most likely due to the high rate of immunosuppression. We cannot confirm all sero-positive patients were infected; published data2 supports the specificity of Strongyloides serology for current infection. We recommend ECCO guidelines and current British Society of Gastroenterology guidelines are adapted to include targetting IBD patients who originate from endemic areas and serological testing be first line. Follow-up of patients is required to assess the impact of treatment on IBD activity.
Competing interests None declared.
References 1. Rahier JF, et al. J Crohn's Colitis 2009;3:47–91.
2. Loutfy MR, et al. Am J Trop Med Hyg 2002;66:749–52.