1. Department of Tropical Parasitology, Interfaculty Institute of Maritime and Tropical Medicine, Medical University of Gdańsk, 81-519 Gdynia
2. Department of Microbiology, Gdańsk University of Technology, 80-952 Gdańsk
3. Department of Biology and Medical Parasitology, Medical University of Poznań, 87-100 Poznań, Poland
4. Laboratory of Parasitology, Statens Seruminstitut, DK-2300 Copenhagen, Denmark
5. Animal and Food Sciences Division, Lincoln University, Canterbury, New Zealand
6. Department of Laboratory Medicine, Karolinska Institute, S14186 Stockholm, Sweden