West Nile Virus

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West Nile Virus

• Adam J. Negley, Emergency Response Coordinator
• Gregory L. Halley, MD, MBA
• Health Commissioner

Wayne County Health Department
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Disease Reporting

• Know your ABCs!
• Reports of suspected and confirmed cases are made
  to the local health jurisdiction of residence.
• Class A1 diseases are to be reported immediately
  by telephone.
• Laboratory reports and physician reports of other
  diseases can be submitted via US mail.

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Credits to other authors

• Adapted from a presentation originally authored
  by
• Anthony A. Marfin, M.D., M.P.H.,
• for a presentation to the Audubon Society of
  Portland, Oregon called the West Nile Virus
  Workshop which was presented on January 16, 2003.

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West Nile Virus Overview

• First isolated
• West Nile District, Uganda, 1937

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West Nile Virus Overview

• Geographic distribution
• Pre-1999 Africa, Middle East, Europe,
  West/Central Asia
• Since 1999 North America
• As of 2003 Found in 45 States
• Vector mosquitoes

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West Nile Virus Overview

• "West Nile Virus" is a flavivirus commonly found
  in Africa, West Asia, and the Middle East.
• It is closely related to St. Louis encephalitis
  virus that has been found in the United States
  for years, and both are transmitted from infected
  birds to man by the bite of an infected mosquito.

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West Nile Virus Basic transmission cycle
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Introduction of West Nile Virus to North America
Possible mechanisms

• Viremic (viruses in blood) human
• Human-transported viremic bird (or other
  vertebrate)
• Legal
• Illegal
• Storm-transported viremic bird
• Human-transported infected vector(s)
• Purposeful introduction (bioterrorist event)

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West Nile Virus New transmission modes United
States, 2002

• Transplanted organs
• Transfused blood
• Breast milk
• Transplacental
• Occupational exposure (percutaneous)

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West Nile Virus Clinical features

• Most human infections silent
• Clinical illness in minority of infections
• Incubation period 2-15 days
• West Nile fever
• Self-limited, flu-like illness
• Fever, headache (rash, lymphadenopathy)

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West Nile Virus Clinical features

• Severe forms (lt1 of WNV infections)
• Encephalitis
• More common in persons gt50 years old
• Case-fatality 10-15
• Meningitis
• Rare
• Hepatitis (Liver),
• Pancreatitis (Pancreas),
• Myocarditis (Heart)

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Human WNV Infections - Mild

• Symptoms in humans
• Mild infections are common and include fever,
  headache, and body aches, often with skin rash
  and swollen lymph glands.

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Human WNV Infections - Severe

• Symptoms in humans
• Headache, high fever, neck stiffness, stupor,
  disorientation, coma, tremors, convulsions, and
  paralysis mark more severe infection.
• At its most serious, WNV can cause permanent
  brain damage and can be fatal.

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Ohio West Nile Virus 2002 2003

• United States 2002 WNV totals
• Cases 3091
• Deaths 181
• Ohio 2002 WNV totals
• Confirmed 140
• Probable 301
• Probable/confirmed deaths 31
• Includes 68 year old Wooster woman

• United States 2003 WNV totals (Oct. 8 2003)
• Cases 6411
• Deaths 134
• Ohio 2002 WNV totals
• Confirmed
• Probable
• Probable/confirmed deaths 4

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WNV Surveillance Strategies

• Bird/Equine
• Dead Bird-First Strategy
• Live Wild Bird
• Equine
• Vector Mosquito
• Larval
• Adult
• Human

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WNV Vaccine Research

• National Institute of Allergy and Infectious
  Diseases
• Research underway on live virus vaccine
• Experimental vaccine with dengue virus as
  backbone
• Phase I Human Trials in 2003

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WNV Prevention Activities

• Clothing (long sleeved shirts/pants)
• Stay indoors early/late in day
• Insect repellants (e.g. DEET)
• Habitat (remove standing water)
• Keep screens/doors in good repair
• Larvicide (water application)
• Adulticide (foggers, aerial spray)