1. Institute of Tropical Medicine, Berlin, Germany,
2. Department of Parasitology, School of Medical Sciences, Maceió, Alagoas, Brazil,
3. National Health Foundation, Alagoas, Maceió, Brazil,
4. Department of Medical Statistics, Free University, Berlin, Germany,
5. Laboratory of Parasitology, University of Leiden, The Netherlands,
6. Faculty of Medicine, Free University Berlin, Berlin, Germany