Transcript Mosquitoes, Control, Salmon and West Nile Virus By: Dirk the “Bug Guy” Morrow BioScience Ltd. Morrow BioScience Ltd. June 12th, 2004

Mosquitoes, Control,
Salmon and West Nile
Virus
By: Dirk the “Bug Guy”
Morrow BioScience Ltd.
Morrow BioScience Ltd.
June 12th, 2004
Introduction
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WNV
The creature
Creature control history
Controlling options
Controlling ideology
Conclusions
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West Nile Virus
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WNV History
What has happened so
far?
2004 arrival?
Questions;
– What are we doing?
– What are they doing?
– What can you do?
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Mosquito Lesson
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West Nile Virus
• First isolated in Uganda in 1937
• Regular outbreaks in Romania, Africa, Western Asia, Egypt, Israel,
India, France, Czech Republic
• Arrived in New York in 1999
• Since spread all across North America
• Found in over 180 species of birds
• Also in seals, alligators, bats, dogs, cats, chipmunks, squirrels,
striped skunks, horses, humans . . .
• Now endemic in eastern North America
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U.S. 2003
• 9862 reported
cases
• 264 deaths
•Countless birds
US Data
10000
9000
8000
7000
6000
cases
5000
deaths
4000
3000
2000
1000
0
1999-2001
2002
2003
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Canada 2003
• Over
1388
reported cases
• 14 deaths
• ~ 356 horse
deaths (2002)
• Countless birds
1400
1200
1000
800
600
400
200
0
1
2
3
4
5
severe cases
0
0
0
314
1388
deaths
0
0
0
13
14
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How did it get here?
• Not known for sure
• Birds?
• Mosquitoes?
The West Nile Virus responsible for the 1999 outbreak in New York was
a lineage 1 virus that circulated in Israel from 1997, suggesting
possible viral importation into North America from the Middle East.
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Where is it now?
• As of 2003. . .
• Alberta,
• Idaho,
• California
• Could it be here?
• Haven’t found it . . .
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2004 Arrival
• Predicted to come into BC either through the Kootenays
or the Lower Mainland
• Likely to see Crows first
• Then mosquitoes, horses and humans (in that order)
• Not always the case
• BC is prepared
• Ready to respond,
• Set up to detect it.
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Corvid Surveillance
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What happens when WNV
arrives to a new area?
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Over time see 1% to 4% of the population will show antibodies against
WNV
Of those affected, about 80% do not have any signs or symptoms of
infection
Of those affected, about 20% will have a ‘flu-like’ illness lasting about a
week
Of those affected, 1% or less will develop serious illness (neurological
illness with meningitis and/or encephalitis) and, of these some will die
Children (not many instances of illness)
Older adults (most affected – particularly if already compromised)
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How does this compare to other
causes of death?
Cause of Death
Number of Deaths in 2000
West Nile Virus
Future est: 3 - 12
All other Infectious and
Parasitic Diseases
Approximate: 33
Invasive Meningococcal
Disease
None
Motor Vehicle related
38
Accidental Falls
16
Smoking-related
674
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What are “They” doing?
• BCCDC (BC Centre for Disease Control)
• Setting up mosquito and bird testing facilities
• Paying for weekly couriers to testing facilities
• Taking lead in WNV announcements
• HA (Health Authoritys)
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Working with us on Public Relations Material
Committing to bird surveillance
Conducting adult mosquito trapping
Fielding calls concerning WNV and Human health
MHOs will be making call whether or not to adulticide
• BCVMA (BC Veterinary Medicine Association)
• Equestrian Vaccination and surveillance
• Fielding calls concerning WNV and Veterinary health
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What does this mean?
• Requirement to investigate mosquitoes
• Possible requirement to control
• Where are mosquitoes found, and how does this
potentially impact fish and fish resources?
• A look at mosquitoes is imperative.
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The Creature
• 3,100+ species worldwide,
• Found on almost all continents,
• Responsible for hundreds of
thousands of deaths each year,
• Only the female bites,
• Blood required for egg production,
• Eat pollen (mostly),
• Many life histories all based on
same life cycle,
• Capable of making the most
annoying sound known to
mankind,
• US military has special units.
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Quick Lesson:
Mosquitoes as Vectors
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Transmission cycle
• Carried by birds
• Amplified by mosquitoes
• Transmitted by “bridging”
vectors
• Manifested in illness
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Species in the Valley
• 24 known species
• Not all transmit WNV (11
possible, 6 OK, 2 well)
• We will be targeting the 2
(may change)
– (C. tarsalis, C. pipiens)
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Mosquito Life Cycle
Prevention
Targets
Main Target for Control
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Habitat requirements
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Water
More water
Little bits of water
Yucky water
Nice water
Always still water
Some vegetation
No vegetation
Only vegetation
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Where to look
• EVERYWHERE!!
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Ditches,
Sloughs,
Ponds,
Containers,
Etc . . .
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Main local Mosquitoes
• Aedes vexans
• Floodwater, low oxygen, “warm” water,
• Cottonwoods, reed grasses, blackberries,
• Main nuisance pest, mostly bite humans, very prolific,
• Culex tarsalis
• Yucky water, high organic,
• usually around livestock,
• High Vector importance, bite anything,
• Culex pipiens
• Less vegetation, any water,
• Often around poultry, roosting areas,
• Important in WNV cycle, mainly a bird-biter,
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Mosquito Control History
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Simon Fraser, 1808,
Eric Hearle, 1926,
Harrison Hotel,
Barrowtown,
LMMCB,
Present day,
• A mix of program structures,
• All with similar control strategies.
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Reasons to control
• Economics . . . .
• Golf courses,
• Outdoor recreation,
• Tourism (RV parks),
• Nuisance . . . .
• Backyard bbqs,
• General pain,
• Disease prevention (Vector control) . . . .
• “Doing something”
• Protect wildlife . . . .
• Birds (raptors)
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Fish Issues / Vector Mosquitoes
• Reduce or eliminate mosquitoes without negatively
impacting fish,
• Food and nutrient value of site,
• Potential poison event,
• Negative alteration of habitat.
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Treatment Options
• “No treatment” is an option . . .
• Habitat alteration . . .
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Mowing vegetation,
Planting vegetation,
Disturbing water surface (fountain or flowing),
Total removal,
• Pesticide Use . . .
– Larval controls . . .
• Mainly using BTI,
• Largest portion of any control program by far,
– Adult controls . . .
• Trying to move away from this,
• Broad spectrum chemical
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No Treatment
• Realizing mosquitoes are temporary,
• Taking personal protection measures,
However . . .
• Control can be accomplished,
• Expectation by public to provide some level,
• Highlights need to prioritize sites
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Habitat Alteration
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Adjust vegetation,
• Reduce but not eliminate
particular mosquitoes,
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Disturb water surface,
• Not practical on large scale (good
for private and golf courses),
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Remove breeding potential,
• Sure fire way to reduce
mosquitoes,
However . . .
• Habitat not only important for
mosquitoes,
• Predators, beneficials, fish, birds,
etc . . .
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Not always possible or practical,
Also highlights need to prioritize sites
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Pesticides
• B.t.i.
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Larval Control
Floodwater
Ponds
Sensitive areas
• Pyrethrin
• Adult Control
• Restricted applications
• Methoprene
• Non fish-bearing water (tough to find in BC)
• Where residual requirement over-rides sensitivities
• Will only be used in catch basins or unconnected waters
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BTI Mode of Action
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Non toxic
Target specific
Not residual
Fast acting
Very effective
However . . .
• Can reduce food source,
• Can affect midges and
chironomids (if applied
incorrectly)
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Adult control – Not recommended
• In response to high levels of WNV,
• “3 bites per minute” – from PUP,
• Ordered by health,
• Working on developing more accountable thresholds.
• How this typically works,
• We would determine high levels of adult mosquitoes (phone calls,
trapping, or personal observation),
• Investigate area for PFZs (Organic farms, sensitive areas,
requested avoidance, wells and water intakes, etc . . .)
• Make a determination if spraying is feasible,
• Schedule treatment,
• Notify residents (likely they would already be aware),
• Conduct treatment,
• Follow-up (did it work?).
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Treatment Summary
Food
Biodiversity effects
Overall impact
BTI
Remove
mosquitoes only
(leaves 3 stages
there)
Limited if late instar treated
Limited
(reduce WNV)
Habitat alteration
(disturb water)
Affect all
inhabitants
Completely
eliminate
mosquitoes
Reduce biodiversity
(reduce WNV)
Habitat alteration
(vegetation)
Affect some
inhabitants
Alter mosquito
species (maybe)
Negligible (not
guaranteed)
Site removal
Remove everything
Eliminates
everything
Negative
(reduce WNV)
No treatment
No effect
Balanced
ecosystem
No reduction in
WNV
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Control Goals
• Nuisance control . . . .
• Elimination?
• Bearability?
• Middle?
• Vector control . . . .
• Zero disease occurrence?
• Transmission reduction?
• Zero death?
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Control Strategy
• Integrated Pest Management
• Don’t “spray everything”
• All available tools
• Focus on best control with least impact
• 6 step program
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Planning
Investigation (species ID and location)
Monitoring
Threshold decisions
Treatment options
Review
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Mapping
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So . . . What to do?
• Map and Monitor . . .
• Follow mosquito population (treat when necessary)
• Indicators of overall health
• Maintain habitat to increase biodiversity
• Assist with predator augmentation
• Not usually possible
• Post information
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What will happen when it arrives?
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Educate! Educate! Educate!!!!
Intense Surveillance
Monitor situation with Health
Increased mosquito control
(mostly larval)
• Public areas????
ATTENTION
MOSQUITOES
• Close parks?
• Signs in other public
areas?
• Educate!
GO AWAY!!
(please)
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What if I find a dead bird?
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Don’t touch it with bare hands
Notify the FHA (call 1-888-WNV-LINE)
Use gloves, shovel or tongs or pick it up doggy bag style
In Langley – bury the bird (not in the vegetable garden)
Report it online if information not given to FHA
(www.bccdc.org)
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Partners in WNV Action Plan
• Province (various ministries)
• Local governments
(regional and municipal)
– Mosquito Control
– Contractors
– Parks
– Engineering
• BC Centre for Disease
Control (BCCDC)
• Canadian Blood Services
• Other Health Authorities
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Animal Health Centre
SPCA
Local Wildlife Rehab Centres
Various Laboratories
Canadian Food Inspection
Agency (CFIA)
Experts in specific areas
Contacts in areas that have
experienced WNV
What can you do?
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Notify Mosquito Control
– Swamp locations
– Adult activity
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Bug proof your home
– Remove development sites
– Screens on windows
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Protect yourselves
– Wear proper clothes
– Use repellent
– Limit exposure
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Recommendations for Outdoors
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Wear long-sleeved shirts, long pants,
and socks when possible
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Spray exposed skin with an insect
repellent
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Wash treated skin with soap and
water after returning indoors
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Spray clothing with products
containing DEET, as mosquitoes may
bite through thin clothing
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Keep doing what you normally do
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DEET
Applications
Per Day
DEET
Concentration
Protection
Time
Under 6
months
0
0
n/a
6 months
to 2 years
1
10% or less
3 hours
Apply only if a high risk of infection
exists
2 to 12
years
3 maximum
10% or less
5 hours
Avoid face and hands
Over 12
years
As required
30% or less
6 hours
Avoid eyes and mouth
Age
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Comments
(Approximate)
DEET should not be used on infants
under 6 months
10 ways to reduce mosquito
breeding around your home
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Things to Watch for
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Other Things to Watch for
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THE END
• 604 986-3363
• www.morrowbioscience.com
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Dirk Lewis,
Biologist/Manager,
[email protected]