http://www.merck.com/!!s9OfD17kBs9OwL2Wwl/disease/preventable/hepb/
Facts on hepatitis B (symptoms, statistics, spread, and prevention).

http://www-medlib.med.utah.edu/WebPath/INFEHTML/INFEC041.html
This site illustrates photomicrographs of blood parasites and has links to other image-containing sites.