'H5 Nl' may be best described as a:
H5N1 is the An Flue a type of Influenza A virus, also called the Bird Flu Virus. Ref: Molecular Medicine: An Introductory Text By Trent, 3rd Edition, Pages 209-10; Clinical Infectious Disease By Schlossberg, 2008, Page 1290
Bird flu virus
Vaccine for HIV
Agent for Japanese encephalitis
New strain of Plasmodium falciparum