1. Laboratory of Parasitology, Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, DK–2300 Copenhagen S, Denmark
2. Department of Pediatrics, Herlev Hospital, Herlev Ringvej 75, DK–2730 Herlev, Denmark
3. Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK–2100 Copenhagen Ø, Denmark
4. Department of Infectious Diseases, Hvidovre Hospital, Kettegård Alle 30, DK–2650 Hvidovre, Denmark