Mosquitoes, Control, Salmon and West Nile Virus

Morrow BioScience Ltd.

Mosquitoes, Control, Mosquitoes, Control, Salmon and West Nile Salmon and West Nile VirusVirus

By: Dirk the “Bug Guy”


June 12th, 2004


Introduction

• WNV• The creature• Creature control history• Controlling options• Controlling ideology• Conclusions


West Nile VirusWest Nile Virus

• WNV History

• What has happened so far?

• 2004 arrival?

• Questions;– What are we doing?– What are they doing?– What can you do?

• Mosquito Lesson


West Nile VirusWest 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


U.S. 2003U.S. 2003• 9862 reported cases

• 264 deaths

•Countless birds

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

1999-2001 2002 2003

US Data

cases

deaths


Canada 2003Canada 2003• Over 1388 reported cases

• 14 deaths

• ~ 356 horse deaths (2002)

• Countless birds

0

200

400

600

800

1000

1200

1400

severe cases 0 0 0 314 1388

deaths 0 0 0 13 14

1 2 3 4 5


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.


Where is it now?

• As of 2003. . .• Alberta,• Idaho,• California

• Could it be here?• Haven’t found it . . .


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.


Corvid SurveillanceCorvid Surveillance


What happens when WNV arrives to a new area?

• 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)


How does this compare to How does this compare to other causes of death?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 MeningococcalDisease

None

Motor Vehicle related 38

Accidental Falls 16

Smoking-related 674


What are “They” doing?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)• 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


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.


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.


Quick Lesson: Quick Lesson: Mosquitoes as VectorsMosquitoes as Vectors

• Transmission cycle• Carried by birds• Amplified by mosquitoes• Transmitted by “bridging”

vectors• Manifested in illness

• 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)


Mosquito Life Cycle

Main Target for Control

Prevention Targets


Habitat requirements

• Water• More water• Little bits of water• Yucky water• Nice water• Always still water• Some vegetation• No vegetation• Only vegetation


Where to look

• EVERYWHERE!!• Ditches,

• Sloughs,

• Ponds,

• Containers,

• Etc . . .


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,


Mosquito Control History

• Simon Fraser, 1808,• Eric Hearle, 1926,• Harrison Hotel,• Barrowtown,• LMMCB,• Present day,

• A mix of program structures,• All with similar control strategies.


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)


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.


Treatment Options

• “No treatment” is an option . . .• Habitat alteration . . .

• 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


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


Habitat Alteration• Adjust vegetation,

• Reduce but not eliminate particular mosquitoes,

• Disturb water surface,• Not practical on large scale (good

for private and golf courses),

• Remove breeding potential,• Sure fire way to reduce

mosquitoes,

However . . .• Habitat not only important for

mosquitoes,• Predators, beneficials, fish, birds,

etc . . .

• Not always possible or practical,• Also highlights need to prioritize sites


PesticidesPesticides

• B.t.i.• 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


BTI Mode of Action• Non toxic• Target specific• Not residual• Fast acting• Very effective

However . . .• Can reduce food source,• Can affect midges and

chironomids (if applied incorrectly)


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?).


Treatment SummaryFood Biodiversity effects Overall impact

BTI Remove mosquitoes only (leaves 3 stages there)

Limited if late in-star 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


Control Goals

• Nuisance control . . . .• Elimination?• Bearability?• Middle?

• Vector control . . . .• Zero disease occurrence?• Transmission reduction?• Zero death?


Control Strategy

• Integrated Pest Management• Don’t “spray everything”• All available tools• Focus on best control with least impact

• 6 step program• Planning• Investigation (species ID and location)• Monitoring• Threshold decisions• Treatment options• Review


Mapping


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


What will happen when it arrives?

• Educate! Educate! Educate!!!!• Intense Surveillance• Monitor situation with Health• Increased mosquito control

(mostly larval)• Public areas????

• Close parks?

• Signs in other public areas?

• Educate!

ATTENTIONMOSQUITOES

GO AWAY!!(please)


What if I find a dead bird?What if I find a dead bird?

• 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)


Partners in WNV Action PlanPartners 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

• 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?• Notify Mosquito Control

– Swamp locations– Adult activity

• Bug proof your home– Remove development sites– Screens on windows

• Protect yourselves– Wear proper clothes– Use repellent– Limit exposure


Recommendations for OutdoorsRecommendations for Outdoors

• Wear long-sleeved shirts, long pants, and socks when possible

• Spray exposed skin with an insect repellent

• Wash treated skin with soap and water after returning indoors

• Spray clothing with products containing DEET, as mosquitoes may bite through thin clothing

• Keep doing what you normally do


DEETDEET

AgeApplications

Per DayDEET

Concentration

ProtectionTime

(Approximate)

Comments

Under 6months

0 0 n/a DEET should not be used on

infants under 6 months

6 monthsto 2

years

1 10% or less 3 hoursApply only if a high risk of infection

exists

2 to 12years

3 maximum 10% or less 5 hours Avoid face and hands

Over 12years

As required 30% or less 6 hours Avoid eyes and mouth


10 ways to reduce mosquito 10 ways to reduce mosquito breeding around your homebreeding around your home


Things to Watch forThings to Watch for

NOT REAL!!!


Other Things to Watch for

REAL!!!


Dirk Lewis,Biologist/Manager,[email protected]

THE END

• 604 986-3363• www.morrowbioscience.com

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Mosquitoes, Control, Salmon and West Nile Virus

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