west nile virus - regional district of central okanagan 5.1a...west nile virus •wnv is an...
TRANSCRIPT
MOSQUITO CONTROL & CHANGES
TO THE WEST NILE VIRUS
PROGRAM 2012
OVERVIEW
• What is West Nile Virus?
• What is the difference between a WNV and a Nuisance
Mosquito Control Program?
• What did the program look like this year (changes)
• What were the challenges?
BETWEEN 2005 & 2011, THE MINISTRY OF HEALTH
SERVICES OFFERED WNV RISK REDUCTION
GRANT FUNDING FOR MUNICIPALITIES, FIRST
NATIONS AND REGIONAL DISTRICTS IN THE
PROVINCE. THE RDCO HAS BEEN APPLYING FOR
THIS FUNDING EACH YEAR. THIS FUNDING HAS
BEEN DISCONTINUED AS OF 2012
BWP Consulting Inc. has been contracted
to assist with the RDCO WNV program
since 2005 and the has been the
responsible for the program since 2011
(2012 is second year of five year contract)
WEST NILE VIRUS
• WNV is an arbovirus…spread by insects
• Arrived in North America in 1999
• Arrived in British Columbia in 2009- 10 mosquito
pools, two humans and 2 horses found infected in
the RDOS
• Detected again in 2010 with one human case and a
number of infected birds in the Central Okanagan
• Horse confirmed positive in Central Okanagan in
2011
The West Nile Virus Cycle
WEST NILE VIRUS
• Causes illness in 20% of infected individuals
• 1% of infected individuals suffer serious illness
• Transmission is interrupted through prevention of
mosquito bites (personal protection or mosquito
control)
• Not all mosquitoes can transmit WNV
? First some biology……
• 29 species of mosquitoes have been identified in
the RDCO
• Females require blood meal to develop eggs
• Males are pollinators of grasses
• All larvae develop in standing water
BASIC MOSQUITO BIOLOGY:
MOSQUITO LIFECYCLE- FOUR STAGES
ADULT
EGGS
LARVA (FOUR INSTARS)
Anopheles
Coquillettidia (Mansonia)
Culiseta
Culex
PUPA (UH-OH)
• Nuisance Mosquitoes (Aedes/Ochlerotatus)
Lay eggs in soil
Eggs become wet with rising water (floodwater mosquitoes)
Larvae develop in 5 days to 10 days
Adults emerge in clouds and can be incredibly aggressive
Usually only bite once, lay eggs and die
Short lived (depending on temp)
More abundant in early season (May-early July)
• Disease Vectors (transmit West Nile
Virus) (Culex/Culiseta)
Lay eggs on surface of water
Eggs hatch within day or two
Larvae develop in about 7-10 days
Adults emerge throughout summer,
not aggressive to humans
Females bite many times (every 2
weeks depending on the weather)
Relatively long-lived
Later season (Late June through
August)
FEMALE MOSQUITOES:
• Selective about who they bite:
• Bird biters
• Human biters
• Horse biters
• Frog biters
• Selective about where they lay their eggs- (so we know where to look for them!):
• Saline ponds
• Highly polluted ditches
• Urban versus rural
• West Nile virus vectors lay eggs, in containers, polluted habitats, catch basins, ditches, flooded fields
• Nuisance mosquitoes lay eggs in flooded fields, near snowmelt and floodwater habitat
FEMALE MOSQUITOES:
• Nuisance:
• Target floodwater &
snowmelt
• Mission creek flooding
• Cattail ponds
• WNV Program
• Target permanent ponds
• Target water left after floods
• Catch basins (Culex pipiens)
• Ditches
DIFFERENCE BETWEEN A NUISANCE MOSQUITO
CONTROL PROGRAM &
WNV VECTOR CONTROL PROGRAM
WHAT WERE THE COMPONENTS OF THE
RDCO NUISANCE MOSQUITO CONTROL
PROGRAM?
Surface water larviciding in floodwater and snowmelt habitats.
Treat Aedes, Ochlerotatus, Anopheles & Coquillettidia larvae
Larviciding in Kelowna, small area of West Kelowna, Lake Country and the Electoral Areas
WHAT ARE THE COMPONENTS OF
THE COMBINED WNV AND NUISANCE
MOSQUITO CONTROL PROGRAM?
1. Public education
2. Mosquito Surveillance
3. Mosquito Control
1. Public education Radio, newspaper & Castanet
Published a brochure & poster boards
Issued press releases
Booths at Farmer’s Market, Kokanee Salmon Fest, Street Festivals, Fintry Fair, events in Lake Country
2. Mosquito Surveillance- trapping adult mosquitoes to determine species composition and abundance.
We had 4 trapping locations in 2012:
(Greenhow Road, Mission, Glenmore Landfill area and Winfield)
2. MOSQUITO TRAPPING
Captured over 3,300 mosquitoes in 2012
399 Culex tarsalis (12% of total catch)
Highest numbers Glenmore followed by Mission Creek
133 Culex pipiens (4.0% of total catch)
Highest trap counts in Mission & Winfield
Nuisance Mosquitoes (Aedes, Ochlerotatus, Anopheles & Coquillettidia) (84% of total catch)
Highest trap counts in Mission
3. Mosquito Control: Habitat Modification
Tire collection starts today!
HOW DO WE CONTROL
MOSQUITOES?
100% larviciding with biological
agents (larvae trapped in the water!)
Active ingredient Bacillus
thuringiensis var israelensis (open
water) & Bacillus sphaericus (catch
basins for Culex control)
Safe for other insects, amphibians,
fish mammals, & reptiles
HOW IS IT APPLIED?
• Backpack blower- like a leaf blower (489.15 kg of
granules applied to 97.8 ha)
• 15,344 catch basins treated with water-soluble pouches
in Kelowna & Lake Country (2 treatments of each
basin).
CHANGES
• Peachland and West Kelowna opted out of the comprehensive
program
Peachland had no control
West Kelowna was reduced to small area around Rose
Valley Elementary & 60 catch basins
• Because of changes
Treated 3,000 less basins
Monitored and treated 35 fewer surface water sites
CHALLENGES
• Fintry Park area
• Many calls from residents and visitors
• Unable to find source- perhaps Lake?
• Residents & staff from West Kelowna
• Bylaw officer concerned because we would not visit owners
with habitat
• Handful of residents upset because we would not visit and it
turned out to be a pretty bad year for mosquitoes
QUESTIONS?