1. Institute of Food and Environmental Hygiene, Faculty of Veterinary Medicine, Latvia University of Life Sciences AndTechnologies, Kr. Helmana Street 8, Jelgava LV-3004, Latvia
2. Department of Biosystematics, Institute of Life Sciences and Technology, Daugavpils University, Parades Street 1a, Daugavpils LV-5401, Latvia
3. Riga Stradins University, Statistics Unit, Balozu Street 14, Riga LV-1007, Latvia