Plague bacterium: Copyright Dennis Kunkel Microscopy, Inc.; smallpox virus: © Meckes, Gelderblom, Eye of Science, Photo Researchers; smallpox victim: CDC / NIP / Barbara Rice
Katku bakter: Copyright Dennis Kunkel Microscopy, Inc.; rõugeviirus: © Meckes, Gelderblom, Eye of Science, Photo Researchers; rõugehaige: CDC / NIP / Barbara Rice