Bulgaria - River Isker.
Industrial plants on the banks of the river.
Stoke industrial waste into the river.
Rubbish in water.
Yugoslavia - Capture animals and animals infected with rabies virus.
Institute.
Pasteur in Novi Sad.
Production of rabies vaccines.
Vaccinations population.
Czechoslovakia - cattle farms and a laboratory for the development of new breeds of pedigree cattle in Gradiste.
Poland - Reserve "Bialowieza Forest" on the territory of Poland.
A herd of bison.
Scientists Branch of the Polish Academy of Sciences conduct research.