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?