Title: Updated West Nile Virus Information for Ohio http:www.odh.state.oh.usODHProgramsZOODISWNVwnv1.htm
1West Nile Virus
Culex quinquefasciatus
2WNV The Basics
- First case reported in 1999, NY 7 dead
- By 2000 spread throughout New England
- 2002, found in most states
- Origin is Egypt, Israel, Asia, Africa
- How did it get here? Human, bird, mosquito
- Encephalitis (inflammation of the brain)
- Meningitis (inflammation of the lining of the
brain and spinal cord) - Currently no human vaccine
3WNV Update 10/02
- The first two human cases of West Nile Virus were
reported on August 14, 2002, one from Cuyahoga
County and one from Franklin County. - As of October 11, 2002, there are 316 probable
cases and 26 confirmed cases of West Nile Virus
in Ohio. - There have been 14 deaths in Ohio.
- Nationwide 3052 cases, 164 deaths
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5West Nile Virus Entomology
- Isolated from 40 mosquito species outside the US
- Mostly Culex species
- Cx. univittatus, Cx. perixiguus, Cx. pipiens, Cx.
modestus, Cx. quinquefasciatus, Cx.
tritaeniorhynchus, and Cx. vishnui - Other mosquito species in a variety of genera
- Aedes, Aedeomyia, Anopheles, Coquillettidia,
Mansonia, Mimomyia - Other species as accessory vectors?
- Isolated from ticks
- Soft tick genera Argas, Ornithodoros
- Hard tick genera Amblyomma, Dermacentor,
Hyalomma, Rhipicephalus,
6West Nile Virus Transmission Cycle
Mosquito vector
Incidental infections
West Nile virus
West Nile virus
Incidental infections
Bird reservoir hosts
7West Nile Virus Reservoir Hosts
- Isolated from numerous wild birds.
- Wetland and terrestrial species.
- Birds are primary amplifier hosts.
- Reservoir status not known.
- Migratory bird role in distribution and
re-introduction of virus into northern latitudes. - Role of other vertebrates not known.
8West Nile Fever Human Disease
- Mild infections are common and include fever,
headache, and body aches, often with skin rash
and swollen lymph glands. - More severe infection is marked by headache, high
fever, neck stiffness, stupor, disorientation,
coma, tremors, occasional convulsions, paralysis
and, rarely, death. - The incubation period in humans is usually 5 to
15 days. - Case-fatality rates range from 3 to 15 (higher
in elderly than in younger age groups). Most
fatal cases 50 years old. - There is no vaccine available for human use.
9West Nile Virus in Wild Birds - 2001
10West Nile Virus in Horses - 2001
11West Nile Virus in Humans - 2001
12West Nile Virus in Mosquitoes - 2001
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16WNV Positive Samples 2001Bird, Mosquito,
Horse, Human
Cuyahoga 185 Franklin 35 Summit 10 Mahoning
10 Lake 13
17WNV Positive Samples 10/2002Bird, Mosquito,
Horse, Human
Lowest 50
18Updated West Nile Virus Information for
Ohiohttp//www.odh.state.oh.us/ODHPrograms/ZOODIS
/WNV/wnv1.htm