Increasing incidence of imported schistosomiasis in Mallorca, Spain

Abstract

Schistosomiasis represents an important public health burden in developing countries. Worldwide, more than 200 million people are infected and approximately 85% of them are living in Africa [1, 2]. Anecdotal observations have suggested the incidence of imported schistosomiasis on the Spanish island of Mallorca has increased in recent years. In order to investigate this possibility, a retrospective study was conducted to determine the epidemiology of infection and the characteristics of patients diagnosed with schistosomiasis in Mallorca over a recent 8-year period. All cases of schistosomiasis diagnosed at the University Hospital Son Dureta, Palma de Mallorca between January 1995 and December 2002 were analyzed. This 878-bed hospital is the largest hospital in Mallorca and serves as the reference microbiology laboratory for the island. Schistosomiasis was diagnosed by microscopic detection of eggs in urine, stool, or semen specimens. Infected individuals were treated with praziquantel 40 mg/kg in a single or divided dose and were scheduled for a follow-up examination 2–6 months after treatment completion. For all patients with schistosomiasis, information pertaining to demographics, clinical characteristics, treatment regimen, laboratory results, and radiological findings was collected and stored in the patient records. This data was retrieved and analyzed in the present study. During the period evaluated, a total of 16 patients were diagnosed with imported schistosomiasis due to the following species: S. haematobium (n=11), S. mansoni (n=2), mixed infection with S. haematobium and S. mansoni (n=2), and an undetermined species thought to be either S. haematobium or S. intercalatum (n=1). Schistosoma eggs were also detected in specimens in which they are not typically present, i.e., S. haematobium in the stool of two patients and the semen of one patient and S. mansoni in the urine of two patients with mixed infection. Nine patients were found to be concomitantly infected with one or more of the following parasites: Blastocystis hominis, Giardia lamblia, Dientamoeba fragilis, Ascaris lumbricoides, Trichuris trichiura, Sarcoptes scabiei, Plasmodium falciparum, and Plasmodium malariae. Mallorca is the largest of the Spanish Balearic Islands with a registered population of 730,778 inhabitants in 2002. In recent years, the number of immigrants has increased, with many arriving from non-European countries [3]. In 1996 a total of 23,410 immigrants was registered in Mallorca and 25% of them were of nonEuropean origin. By 2002, the number of immigrants had increased to 76,916 and 45% were from non-European countries. The majority of the non-European immigrants arrived from South America (n=18,239) and Africa (n=11,571), with many also arriving from Asia (n=2,323) and Central America (n=1,945). In most of these geographic areas schistosomiasis is endemic. As shown in Fig. 1, the incidence of schistosomiasis in Mallorca rose considerably during the period studied, as did the number of immigrants of non-European origin. The median age of infected individuals identified in our evaluation was 24 years (range, 6–48 years), and 94% were male. All of the schistosomiasis infections were acquired in Africa. Only one patient was a traveler, and this Spanish national had contracted schistosomiasis while visiting Mali. The remaining 15 patients were all African M. Rotger . T. Serra . M. G. de Cardenas . A. Morey Division of Clinical Microbiology, University Hospital Son Dureta, C/Andrea Doria 55, 07014 Palma de Mallorca, Spain