The West Nile Virus A Global and

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The West Nile Virus – A Global and Local Concern Add Corporate Logo Here Amleto A. Pucci, Jr. Ph. D. P. E. Director, Bureau of Environmental Health Bucks County Department of Health

Outline • Global Extent • United States Program • Science – Vectors, hosts – Transmission cycle • Surveillance & Control • NYC Case study • Bucks County Data

West Nile Outbreaks • • Uganda - 1937 (first diagnosed case) Israel - 1951 -1954, 1957, 2000 France - 1962, 2000 South Africa - 1974 Romania – 1996 Italy 1998 Russia - 1999 United States – 1999 -2000 Modified from

West Nile Fever: Classical Clinical Description • Asymptomatic or mild dengue fever-like illness • Fever, headache, abdominal pain, vomiting, rash, conjunctivitis • Incubation period usually 3 to 15 days • CNS involvement and death in minority of cases Modified from

West Nile Virus in the US Some Possible Pathways of Introduction • • • Infected human host Human-transported vector(s) (agent) Human-transported vertebrate host (carrier) – Legal – Illegal • Storm-transported vertebrate host (bird) • Intentional introduction (terrorist event)

Partnerships for West Nile Virus in the United States • • Centers for Disease Control and Prevention U. S. Department of Agriculture U. S. Geological Survey Department of Defense Environmental Protection Agency State and Local Health Departments State and Local Veterinarians State and Local Wildlife Biologists

Jurisdictions Funded for Enhanced WN Surveillance New York City Philadelphia Washington, D. C. Los Angeles Houston First Round $$ Second Round $$

West Nile Fever: Background and Epidemiology • Basic transmission cycle involves mosquitoes feeding on birds infected with the West Nile virus • Infected mosquitoes then transmit West Nile virus to humans and animals when taking a blood meal Modified from

Virus • Virus uses birds as amplifier hosts, with vectors that feed on birds. • Virus strain is highly infectious for North American birds, causing mortality and high viremia. • Virus does not transmit from infected mosquito to next mosquito generation. • Virus overwinters in some mosquitoes.

West Nile Virus Transmission Cycle Modified from

Estimated Sensitivity of West Nile Virus Surveillance Methods Surveillance method Human cases Disease Activity Veterinary cases Mosquitoes, sentinel hosts Dead bird Time

Integrated Mosquito Management • Surveillance – Bird – Mosquito – Human • Larval Mosquito Control – Source reduction – Appropriate response to the need • Adult Mosquito Control – Targeted Approach – based on field data • Education - Outreach

Mosquito Trap methods used by West Nile Virus Program Bucks County Department of Health, ABC Mosquito Light Trap Gravid Trap Modified Aspirator

Types of Mosquito Control used in the Bucks County West Nile Virus Program • Bti (Bacillus thuringiensis isrealensis) – naturally occurring soil bacteria which disrupts the gut of the larvae – Essentially nontoxic to humans – Does not effect wildlife and non-target species • Methoprene “Altocid” -- chemical growth regulator – Low toxicity to mammal, birds, and fish. – Some invertebrates are sensitive to it therefore strictly controlled. – Not unreasonable risk to the environment. Breaks down quickly.

1999 WN virus activity in NYC area Mosquitoes Birds Humans

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Select West Nile Virus Research Priorities • Virus persistence mechanisms (disease reservoir) • Vector (mosquito species) relationships and range – Mosquito biology and behavior • Vertebrate host (birds) relationships and range – Bird migration as dispersal mechanism • Current & future geographic WNV distribution • Development of preventative strategies – Improved lab diagnostic tests – Clinical studies of human infections – Vaccine development

Key Messages • Best thing is to eliminate places where mosquitoes breed. • Public Health is working hard to reduce mosquito populations in Bucks County. • If you have questions call West Nile Virus Hotline (1 -877 -PAHEALTH), and contact your physician.

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