Regarding the hygienic aspects of the production and use of animal wastes, further research on the following aspects is essential: pathogenic agents present in residues of animal production in the context of transmissible multifactorial diseases and the epidemiology of pathogens under different ecological conditions; recycling of toxic agents, e.g., copper, selenium and iodine, in animal wastes in the context of the food chain from soil to humans; hygienic effects of animal wastes on water as regards the standards required by medical authorities; effects of agents used to increase animal production, or used for medicinal purposes, which are present as residues in animal excreta and may be hazardous to public health; effects of animal excreta on microbiological processes in the soil; effects of dust and airborne microbial emissions from animal production, and finally, processes of self-disinfection of manure and livestock slurry during storage as a means of reducing the amounts of chemical disinfectants used, of reducing environmental pollution, and of studying the application of biotechnological methods to disinfect manure and livestock slurry, this study being of particular importance.