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Virology: Classification of West Nile Virus

	Image A. View enlarged image.	Image B. View enlarged image.
	Scanned images are of West Nile virus isolated from brain tissue from a crow found in New York. The tissue was cultured in a Vero cell for a 3-day incubation period. The Vero cells were fixed in glutaraldehyde, dehyrated, placed in an Epon resin, thin sectioned, placed on a copper grid, and stained with uranyl acetate and lead citrate. The grids were then placed in the electron microscope and viewed. Total magnifications, image A:   65,625x;  image B:  171,250x.  Image courtesy of Bruce Cropp, Microbiologist, Division of Vector-Borne Infectious Diseases.

• Family: Flaviviridae
• Genus: Flavivirus Japanese Encephalitis Antigenic Complex
• Complex includes: Alfuy, Cacipacore, Japanese encephalitis, Koutango, Kunjin, Murray Valley encephalitis, St. Louis encephalitis, Rocio, Stratford, Usutu, West Nile, and Yaounde viruses.
• Flaviviruses: share a common size (40-60nm), symmetry (enveloped, icosahedral nucleocapsid), nucleic acid (positive-sense, single stranded RNA approximately 10,000-11,000 bases), and appearance in the electron microscope. Therefore, images of West Nile virus are representative for this group of viruses.