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     sirinrat wanapinpong , Genetics
                    West Nile virus
• West Nile Virus is a mosquito-transmitted disease
• The virus can infect humans, birds, mosquitoes, and other
• The mosquito-borne virus that causes West Nile fever ( West
  Nile encephalits )
                    West Nile virus
• belongs to the family Flaviviridae
• The virus is closely related to other flaviviruses including for
  St. Louis encephalitis, Japanese encephalitis and Murray
  Valley encephalitis.
                   West Nile virus
• The virus is named after the area it was first found in
  Uganda in 1937
• Today it is most commonly found in Africa, West Asia,
  Europe, and the Middle East
• an outbreak in New York in September, 1999.
West Nile virus
          Structure of west nile virus
• Common size ~ 60 nm
• Symmetry
  (envelope, icosahedralnucleocapsid,
  ~ about 500 angstroms in diameter)
• Nucleic acid (positive sense, single strand RNA , ~10,000-
  11,000 nucleotide base)
surface proteins in a West Nile viral particle these proteins
enable the virus to bind with and invade a host cell.
• the envelope protein molecules that compose the surface of a
  West Nile virus particle
• The West Nile virus is formed from three protein types
• The proteins self-assemble in a host cell, forming a well-
  organized geometric shape
The major surface protein is composed of
three domains color-coded pink, yellow and blue
            Infection of west nlie virus
• the most vulnerable birds are often killed by the virus
• 17 species of birds have been found infected by the virus
• The infected mosquitoes then transmit the virus when they
  bite and suck blood from people and animals and, in the
  process, inject the virus into their victim.
Typical transmission of WNV
• the time from infection to the development of symptoms, is 5 to 15
• Humans are what are called a dead-end host
• The virus is not known to spread from person-to-person contact such
  as touching, kissing, or caring for someone who is infected
• Moreover the infected ticks can transmit the virus but the data is
• Most people who get infected with the virus do not get sick or show
  any symptoms
• 2 to 14 days after initial exposure
• fever, headache, stiff neck, muscle weakness, skin rash and swollen
  lymph glands
  (west nlie fever)
• a serious illness involving inflammation of the brain (encephalitis) and
  spinal cord (meningitis) and, infrequently, death
                     Risk in human
• People over 50 years of age have the highest risk of
  developing severe illness because, as we age, our bodies have
  a harder time fighting off disease
• People with weakened immune systems are also at increased
  risk; however, anyone can get the virus
         an increased risk for infection
• highest during the mosquito season when freezing
  temperatures are experienced
• In temperate areas of the world, cases of West Nile virus
  occur primarily in the late summer or early fall
• In southern climates where temperatures are milder,virus can
  occur year round.
            Treatments & Vaccines

• There is no specific treatment or vaccine against West Nile
Vaccine developed for West Nile virus
         Vaccine developed for West Nile virus
• effectively protects monkeys from the infection.
• tested two versions of the West Nile/dengue 4 virus vaccine
  in monkeys
       1 combined West Nile virus proteins with the entire
  dengue virus genetic material
       2 combined West Nile virus proteins with a modified
  dengue virus.
• The vaccine containing the modified dengue virus was more potent in
  eliminating viruses from the blood
• The combination vaccines also that successfully fought the infection
        produced high levels of antibodies
       a reduced level of virus or no signs of the virus present in the
       no West Nile virus infection was found
reduce the risk of an outbreak of the West
                Nile fever
• surveillance of birds that are sick or have died of disease, for
  the virus
• watch out for stagnant water
• control the widespread mosquito
the areas where mosquitoes like to breed
• Wearing appropiate colting whenever you are outdoor at
  dawn, dusk
• Screening your house
• Using repellents containing DEET

• http://my.webmd.com/webmd_today/home
• http://ftp.purdue.edu/pub/uns/kuhn.westnile.
• http://www.epa.gov/pesticides/factsheets/sk
• http://www.publichealthgreybruce.on.ca/

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