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Slide3: 

West Nile Virus: Background and Ecology First isolated in West Nile district, Uganda, 1937 Commonly found in humans and birds and other vertebrates in Africa, Eastern Europe, West Asia, and the Middle East, but has not previously been documented in the Western Hemisphere 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

West Nile Virus Outbreaks: 

West Nile Virus Outbreaks Israel – 1951-1954, 1957, 2000 France – 1962, 2000 South Africa –1974 Romania – 1996 Italy – 1997 Russia – 1999 U. S. A. – 1999-2002

Spread of West Nile Virus in the U.S. 7/30/02: 

Humans 2001 2000 1999 2002 Spread of West Nile Virus in the U.S. 7/30/02

Slide6: 

WNV Case-Patient Demographics & Mortality United States, 1999-2001

Date of Symptom Onset, West Nile VirusUnited States, 1999-2001: 

Date of Symptom Onset, West Nile Virus United States, 1999-2001

Clinical Epidemiology: 

Clinical Epidemiology Incubation period 3 - 14 days 20% develop “West Nile fever” 1 in 150 develop meningoencephalitis Advanced age primary risk factor for severe neurological disease and death

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West Nile Fever: Classic Clinical Description Mild flu-like illness of sudden onset Duration 3 - 6 days Fever, swollen lymph nodes, headache, abdominal pain, vomiting, rash, conjunctivitis, eye pain, anorexia Symptoms of West Nile fever in contemporary outbreaks not fully studied

Symptoms of Hospitalized Patients withWest Nile Virus: 

Symptoms of Hospitalized Patients with West Nile Virus 2% Swollen Lymph Nodes 19% Rash 27% Diarrhea 46% Change in mental status 47% Headache 51% Vomiting 53% Nausea 56% Weakness 90% Fever

Risk of West Nile Virus Transmission Through Blood Transfusion: 

Risk of West Nile Virus Transmission Through Blood Transfusion Concern: most WNV infections have no or only mild symptoms, and transient viremia occurs after infection Transfusion-transmission of WNV or other related flaviviruses not reported, but plausible Mathematical modeling: estimated risk of transfusion-transmission was 2 in 10,000 during NYC outbreak (Transfusion, Aug 2002) WNV should be considered in persons who develop unexplained fever, meningitis, or encephalitis after transfusion

Slide12: 

West Nile Virus

Mosquitoes: 

Mosquitoes Usually Culex Genus Pipiens or Restuans species are most common carriers in this area Only the females bite Males feed on nectar Normally only ¼ “ long “Huge” mosquitoes are really crane flies

Mosquito Lifecycle: 

Mosquito Lifecycle Egg raft Up to 300 eggs Hatch within 3 days Larvae Wigglers Pupae Tumblers Become adults within a few days Adult Males Live one week Females live one month Flight range up to ½ mile

West Nile VirusTransmission Cycle: 

West Nile Virus Transmission Cycle Mosquito infects bird while taking a “blood meal” Other mosquitoes pick up the virus from the infected bird Humans and animals (horses) get the virus from infected mosquitoes ONLY MOSQUITOES CAN SPREAD WEST NILE VIRUS

West Nile VirusTransmission Cycle: 

West Nile Virus Transmission Cycle

Dead Birds: 

Dead Birds Virus found in over 100 species of birds Predominant species: Hawks Owls Crows Blue jays Call 1-877-PA HEALTH Only five birds are tested weekly

Hawks: 

Hawks Length: 18 inches Wingspan: 48 inches Short, dark, hooked beak Large, broad-winged, broad-tailed hawk Immatures have notably narrower wings and tail, and appear slimmer Dark patagial mark on underwing, present on all ages and races, is unique

Owls: 

Owls Length: 8 inches Wingspan: 22 inches Small, nocturnal, predatory bird Large, rounded head with ear tufts Yellow eyes Dense streaking on underparts with finer barring Some birds have rusty plumage, others dark gray

Bluejays: 

Bluejays Length: 10 inches Black sturdy bill Blue crest and upperparts Black eyeline and breastband Grayish-white throat and underparts Bright blue wings with black bars and white patches Long blue tail with black bars and white corners Dark legs

Crows: 

Crows Length: 17 inches Entirely black plumage Squared-off tail Very common in urban and agricultural areas

Washington CountyWNV Program: 

Washington County WNV Program Surveillance of known problem areas Surveillance of citizen complaints Samples sent to PA DOH for analysis Positive areas are treated Heavily infested areas are treated Purpose is not to eradicate the mosquito population

West Nile Virus Surveillance: 

Dead Bird Reports Dead Bird Testing Live Bird Testing Mosquito Testing Equine Cases Human Cases West Nile Virus Surveillance

Gravid Trap: 

Gravid Trap Lactalbumin water is an attractant Draws mosquitoes into trap from the bottom Easier to use More effective than light traps

Gravid Trap: 

Gravid Trap

Light Trap: 

Light Trap Carbon dioxide and light used as attractants Color Collection bin hangs from the bottom

PREVENTION: 

West Nile Virus – Human Cases MosquitoControl Personal Protection PREVENTION

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Avoid black and white Wear long sleeves Wear long pants Personal Protection Clothing

Slide29: 

Home needs to be “Bug Tight” Stay indoors at dusk and dawn Use insecticides at dusk and dawn Use white incandescent lights Vitamin “B”, “Bug Zappers”, and “ultrasonic” devices are ineffective Personal Protection Avoidance

Slide30: 

Repellant Deet Bite Blocker Avon Skin So Soft Read and understand label directions Apply lightly to skin and clothing Personal Protection

Mosquitoes Can Kill: 

Mosquitoes Can Kill

Mosquito Control: 

Mosquito Control

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Mosquito Control Habitat Elimination Adulticiding Larviciding

Adulticiding: 

Adulticiding Malathion Organophosphate Applied in “Ultra Low Volume” Can be toxic to humans Originally, only done for positive test areas Will be done for heavy infestations

Larviciding: 

Larviciding Preferred method of control Microbial – BTI, CG, and WDG Naturally occurring bacteria Non-toxic to humans and animals Methoprene Growth regulating hormone Applied to ditches, ponds, marshes Temephos Organophosphate pesticide Can pose a human health hazard Monomolecular films & Oils Causes larvae and pupae to drown Poses little risk to humans, wildlife, and the environment

Natural Predators: 

Natural Predators Purple Martins Bats Mosquito fish Other breeds of mosquitoes Mosquitoes are not the meal of choice

Habitat: 

Habitat Catch basins Clogged bodies of water Construction depressions Flooded Flower pots Public dumps Birdbaths Unfiltered swimming pools Cemetery urns Clogged rain gutters Boats Rain barrels Hoof prints Swamps Tree holes Tin cans Tires

Control Breeding Sites: 

Control Breeding Sites Turn over pools and wheel barrows Dispose of things that can hold water i.e. tires, tin cans, broken toys, etc. Drill holes in permanent containers Clean clogged roof gutters Empty accumulated water from boats Keep outdoor water fresh Landscape your property Keep grass cut and weeds pulled

QUESTIONS?: 

QUESTIONS? THANK YOU!