Hello jat-ga
I hope these resources are what you are seeking. Most of the URLs
provide detailed information about the viruses as well as the
pictures.
WEST NILE VIRUS
Here is a page from the CDC (Center for Disease Control and
Prevention) with two electron micrographs of the West Nile Virus in
the brain tissue of a crow:
http://www.cdc.gov/ncidod/dvbid/westnile/virus.htm
The description states: “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.”
The CDC site also has a page with a line diagram of the virus
structure plus lots of information about the virus:
http://www.cdc.gov/ncidod/eid/vol7no4/petersen.htm is the main page,
and an enlarged version of the diagram is at
http://www.cdc.gov/ncidod/eid/vol7no4/petersenG2.htm
“An icosahedral nucleocapsid (half shown here) encloses the virion
RNA. The virion has an envelope derived from the host cell membranes.
E-glycoprotein (E), an integral membrane protein, is arranged as
homodimers (head-to-tail) and associates with the other integral
membrane proteins prM protein (in immature virions).”
SMALLPOX
Here is a page from Manbir Online with electron micrographs of the
smallpox (variola) virus:
http://www.manbir-online.com/diseases/smallpox-2.htm
“Smallpox belongs to the Orthopox virus genus. Poxviruses are very
large, brick-shaped viruses about 300 x 200 nm (the size of small
bacteria). They have a complex internal structure - a large
double-stranded DNA genome (about 200 kbp in size) is enclosed within
a core that is flanked by 2 lateral bodies. The surface of the virus
particle is covered with filamentous protein components, so that the
particles have the appearance of a ball of knitting wool. The entire
particle is enclosed in an envelope derived from the host cell
membranes.”
Some superb coloured pictures of the virus and also of its life cycle
(click on each picture to view an enlarged imange):
http://www.rkm.com.au/VIRUS/SMALLPOX/index.html (web site of Russell
Kightley Media)
The site All the Virology on the WWW has a tutorial on pox viruses
with a detailed drawing of the structure at
http://www.tulane.edu/~dmsander/WWW/335/Poxviruses.html
NB: Although West Nile Virus is icosahedral, note that the smallpox
virus has a more complex structure. Also, West Nile Virus contains
RNA, while smallpox virus contains DNA.
Search strategy:
I started on the web site “All the Virology on the WWW”, which is a
resource that was already known to me:
http://www.tulane.edu/~dmsander/garryfavweb.html
This contains “The Big Picture Book of Viruses”, which lists links to
pictures of viruses available on the Internet. I turned to the
alphabetical list of viruses in the Picture Book This told me that
the West Nile Virus belongs to the Flaviviridae group. I then turned
to the list by disease, and this told me that smallpox is caused by
the variola virus from the Poxvirus group.
Following the Flaviviridae link in the Picture Book list by family, I
found there were no pictures there, but there was a link to the main
All the Virology page with links to other web sites about
Flaviviridae. This includes a group of links to West Nile Virus
information. I followed some of these links to find the
electromicrographs.
I tried a Google image search for “West Nile”, but this was not
helpful. Going by the statement that West Nile Virus is
representative of its group, I searched for images of “flavivirus”,
which led me to the line drawing of the virus structure.
I did a Google image search on smallpox and another on variola and
selected the best images retrieved. I also searched with the main
Google engine on the terms: variola, structure |
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