Eosinophilia: A Poor Predictor ofStrongyloidesInfection in Refugees

Abstract

BACKGROUND: Canada resettles 10,000 to 12,000 refugees annually. Despite this being a highly vulnerable population, there are little Canadian data on subclinical tropical diseases harboured in this population over the past 20 years.OBJECTIVES: To determine the seroprevalence and predictors ofStrongyloidesinfection in refugees arriving in Edmonton, Alberta.METHODS: A retrospective chart review of all refugees seen at the New Canadians Clinic between March 2009 and April 2010 was performed. Demographic, symptom and physical examination data were collected from the charts. Laboratory results were obtained from the electronic laboratory records.RESULTS: A total of 350 subjects were studied. The overall seroprevalence of strongyloidiasis was 4.6%. Equivocal results were found in 6.3%. In the positive group, the majority were male (62.5%); 75% were born in Africa (P=0.004) and 81.2% lived in refugee camps in Africa (P=0.002). Eosinophilia was present in 25% of the positive subjects (P=0.05), in none of the equivocal group and in 8.7% of the negative group.DISCUSSION: Persistent asymptomaticStrongyloidesinfection is maintained for years through autoinfection. Traditionally, eosinophilia was used as one of the key tools to diagnose chronic but stable diseases, but it was shown to have a poor predictive value for strongyloidiasis in returning expatriates as well as in those presenting with a disseminated form of the disease. It is important to raise awareness of the severe limitations of eosinophilia as a marker for strongyloidiasis when managing patients who either are immunocompromised, or about to start immunosuppressive therapy.CONCLUSIONS: The present study indicated that eosinophilia is a poor predictor of seropositivity and, thus,Strongyloidesinfection. Residence in Africa (birth/refugee camps) proved to be a significantly better predictor ofStrongyloidesseropositivity.