1. West Nile Virus Program Technician J. Roy Houston Conservation Center
Chelsea Gross
West Nile Virus Program Technician
J. Roy Houston Conservation Center
July 26th, 2017

2. Make Your Backyard Less Inviting For Mosquitoes

3. Mosquito Life Cycle Egg Larva 4 Instars Pupa Adult
Drawing by Brett Crans of Rutgers University

4. Mosquito Diet Mosquitoes use their proboscis to feed
Females feed on blood and nectar
Females lay their eggs after a blood meal
Males feed ONLY on nectar
Female
Male

5. West Nile Virus History
West Nile Virus (WNV) was isolated in 1937 in the West Nile District of Uganda
WNV was first found in the United States in 1999 in New York City, New York
In 2000, WNV was found in Pennsylvania
In 2002, WNV was found in Westmoreland County
By 2002, WNV was found across the entire United States

6. In 2002 there were 60 human cases of WNV, in 2016 16 human cases.

7. A mosquito feeds on a bird infected with WNV
The mosquito feeds on another host (bird, human, horse, mammal) and transmits WNV
The bitten host becomes infected with WNV
Birds infected with WNV continue to infect new mosquitos that feed on them
Humans and horses are dead-end hosts, meaning they cannot transmit WNV

8. West Nile Virus Transmission
Amplifier Vectors:
Culex pipiens
(Northern House Mosquito)
Culex restuans

9. West Nile Virus Symptoms
Most people infected do not develop symptoms (70-80%)
Mild symptoms are flu- like
Fever
Headaches
Body aches
Rash
Joint pains
Vomiting
Diarrhea
Less than 1% develop severe symptoms
Encephalitis
Meningitis
Coma
Seizures
Disorientation
Tremors
Neck Stiffness

10. Zika Virus History
Zika Virus was found in 1947 in the Zika forest of Uganda
In 2016, the first local transmission of Zika Virus was found in the United States in Florida and Texas
There have been NO local cases of Zika Virus in Pennsylvania
All Zika cases in PA have been travel related

11. A mosquito bites a host (human) infected with Zika Virus
The mosquito becomes infected with Zika Virus
The mosquito bites another host and can transmit Zika virus
Different from WNV in that humans can transmit Zika virus to mosquitoes

12. Zika Virus Transmission
Amplifier vectors:

13. Zika Virus Transmission
One specimen of Aedes aegypti was collected in Pennsylvania in 2002
It is believed to be a possible misidentification
Aedes albopictus is commonly collected in urban centers across PA

14. Zika Virus Symptoms Most people infected will not have symptoms
Mild symptoms include:
Fever
Headache
Rash
Red eyes
Joint and muscle pain
Zika Virus in pregnant women causes microcephaly
The brain does not develop during pregnancy or after birth
Babies are born with smaller heads than expected

15. Surveillance in Westmoreland County
Adult and larval mosquito monitoring April through October
Mosquitos collected in gravid or BG sentinel traps are sent to the DEP lab

16. Surveillance in Westmoreland County
Aedes albopictus, Asian Tiger mosquitoes, are collected in BG sentinel traps to determine the state localization
Culex sp. are tested for West Nile Virus

17. Surveillance in Westmoreland County
Larval control
When larvae or pupae are detected source reduction or pesticides are used
Dead birds that appear to be suspicious are asked to be reported
Corvids: crows and bluejays
Raptors: hawks, owls, eagles, and falcons
Human and horse cases of WNV are reported by veterinarians and physicians

18. Make Your Backyard Less Inviting for Mosquitoes
Reduce standing water!!!

19. Outdoor Containers Empty buckets and keep them flipped over
Put toys away that could fill with water
Dump out water in overflowing flowerpots
Keep wheelbarrows flipped upright
Turn over plastic wading pools
Drill holes in recycling bins
Keep boats covered when not in use

20. Birdbaths Change water in birdbaths weekly
Use mosquito dunks to treat mosquito larvae

21. Roof Gutters Clean roof gutters every year
Leaves can clog gutters allowing them to hold water
Gutters can produce millions of mosquitoes each year

22. Tires Old tires can produce millions of mosquitoes
Remove sidewalls, drill holes, or keep rims on
Treat tires with larvicides: Bti
College of Agricultural Sciences
Agricultural Research and Cooperative Extension

23. Ornamental Ponds Aerate ornamental ponds to eliminate stagnant water
Fill ornamental ponds with predators such as fish or frogs

24. Puddles/Ruts Alter the landscape to eliminate standing water
Fill in ruts on the property
Do not drive on wet soil

25. Unattended Pools/Pool Covers
Maintain, chlorinate, and clean swimming pools
Run filter in swimming pools
Raise pool covers to keep them from collecting water

26. Rain Barrels
Rain barrels should be covered with wire mesh or a lid to keep mosquitoes from laying their eggs

27. Window Wells
Keep widow wells covered

28. Treat Stagnant Water
Anyone can purchase larval control products at local home stores
Mosquito Bits
Mosquito Dunks
The active ingredient is Bacilius thuringiensis israelensis (BTI)
A bacteria that specifically targets the gut of the mosquito

29. Protection Against Mosquito Bites
Wear long sleeves and pants during peak mosquito activity times (dusk and dawn)
Use repellents according to the label
DEET
No more than 10% DEET for children
Picardin
IR3535
Oil of Lemon Eucalyptus
NOT labeled for use on children
Keep screens on windows and doors

30. More Information
Pennsylvania’s West Nile Virus Control Program
Centers for Disease Control and Prevention
U.S. Department of Agriculture
U.S. Geological Survey
Pesticide Education Program- Penn State University
Environmental Protection Agency
National Pesticide Information Center
PA Vector Control Association

31. West Nile Virus Program Technician
Chelsea Gross
West Nile Virus Program Technician
P: ext. 116

32. Questions?