1. Doñana Biological Station-CSIC, PO Box 1056, 41080 Seville, Spain
2. Catalonian Reptile and Amphibian Rehabilitation Centre (CRARC), 08783, Masquefa, Barcelona, Spain
3. Department of Health Microbiology and Parasitology, University of Barcelona, Avda Joan XXIII s/n, 08028 Barcelona, Spain
4. Current address: Department of Population Biology, Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, CZ-675 02 Konesin, Studenec 122, Czech Republic