hepatitis D

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A viral hepatitis that is either acute or chronic, caused by an RNA virus and occurring either simultaneously with acute hepatitis B or as a superinfection in chronic hepatitis B. It is transmitted primarily by exposure to infected blood or blood products and is most prevalent in tropical and subtropical areas of the Mediterranean basin.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun an acute form of hepatitis, transmitted by blood, sexual contact, and body fluids.