http://www.flickr.com/photos/adamjlynch/3098383957

Smallpox

http://www.flickr.com/photos/ajc1/1257163357

Virus

http://www.flickr.com/photos/kaibara/2234750993

Bacteria

http://www.flickr.com/photos/kalexanderson/5421517469

SICK

http://www.flickr.com/photos/gatesfoundation/4774363781

Polio

http://www.flickr.com/photos/ashclements/54559142

TB

http://www.flickr.com/photos/microagua/3393227206

Protozoa

http://www.flickr.com/photos/ringai/3974639591

Antigen

http://www.flickr.com/photos/andywilkes/3479998109

Chicken pox

http://www.flickr.com/photos/rachel_s/1773289807

Fungi