Peel Public Health Vector-Borne Disease 2016 Technical ... · This report summarizes Peel Public...
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Peel Public Health Vector-Borne Disease 2016 Technical Report & 2017 Prevention Plan
Transcript of Peel Public Health Vector-Borne Disease 2016 Technical ... · This report summarizes Peel Public...
Peel Public Health
Vector-Borne Disease
2016 Technical Report &
2017 Prevention Plan
Table of Contents
Executive Summary ................................................................................................ 1
Introduction ............................................................................................................. 3
West Nile Virus ....................................................................................................... 3
o Surveillance Human Case ..................................................................................... 5
Adult Mosquito .................................................................................. 7
Larval Mosquito ............................................................................... 11
o Larval Mosquito Reduction ........................................................................ 14
o Pesticide Effects and Monitoring .............................................................. 299
o Risk Assessment and Adulticiding ............................................................. 21
o Public Education and Outreach Activities .................................................. 22
Lyme Disease ..................................................................................................... 315
o Human Cases and Surveillance ............................................................... 315
o Tick Surveillance ........................................................................................ 27
o Public Education Activities ......................................................................... 28
Eastern Equine Encephalitis ................................................................................. 28
Other Vector-Borne Diseases of Interest .............................................................. 29
o Reportable Diseases.................................................................................. 29
Malaria, Yellow Fever, and Dengue Hemorrahgic Fever ................. 29
o Non-reportable Diseases ........................................................................... 29
Zika Virus and Chikungunya ........................................................... 29
Conclusions .......................................................................................................... 30
1
Executive Summary
This report summarizes Peel Public Health’s Vector-Borne Disease (VBD) program
activities in 2016 and discusses the activities that will be carried out in 2017.
In Ontario, West Nile Virus (WNV) and Lyme disease are the two main endemic vector-
borne diseases of public health importance as both of these diseases can be acquired
within the province. Peel Public Health’s approach to VBD control emphasizes disease
prevention in humans and protection of the environment through region-wide
surveillance and Integrated Mosquito Management (IMM). The goal of the program for
2017 is to minimize the impact of VBD on human health through region-wide
surveillance and IMM. These activities emphasize public education, source reduction
and larviciding. Information from past seasons was used to guide the activities planned
for 2017.
Surveillance of mosquitoes provides early warning signs on the risk to human health.
Surveillance data is used to enhance mosquito reduction and education efforts on
mosquito and tick protection/prevention before it can significantly impact human health.
Surveillance data indicates that WNV is endemic in Peel and WNV activity levels can
fluctuate widely from year to year.
2016:
In 2016, there were 63 positive WNV mosquito traps and 6 confirmed human WNV
cases. The VBD team followed up on 310 service requests, identified 1695 standing
water sites, referred 553 standing water sites for larviciding, and had approximately
100,000 catch basins in Peel Region treated with larvicide three times from June to
September.
To date, an established blacklegged tick (Ixodes scapularis) population has not been
identified in Peel (the tick responsible for transmitting Lyme disease), although there are
numerous sites in Peel region that have a combination of environmental factors that
would support new populations of blacklegged ticks to become established in the future.
In 2016, four confirmed human Lyme disease cases were reported in Peel; all were
associated with travel, not locally acquired. Thirty seven tick samples were submitted to
Peel. Of the ticks found in Peel six were blacklegged ticks; five were negative for
Borrelia burgdorferi, the bacteria responsible for Lyme disease, and as of February 24,
2017 one is pending further test results. Tick specimens were submitted to the Central
Public Health Laboratory (CPHL) in Toronto for species confirmation. In May and June
of 2016, active tick surveillance was undertaken in Mississauga in an area where a
blacklegged tick was found by a resident. The tick dragging did not identify any further
ticks.
2
2017:
In 2017, Peel Public Health will continue to conduct surveillance and education activities
for both the public and medical professionals related to VBDs. Efforts to reduce
mosquito breeding through source reduction and larviciding in urban and suburban
areas of Peel will continue. Due to population growth, two new mosquito trap locations
will be set in Brampton for a total of 33 traps set in Peel weekly.
Peel Public Health will also continue to examine ticks submitted by Peel residents to
identify sites where blacklegged ticks may be present and conduct active tick
surveillance when warranted.
3
Introduction
This report presents a summary of activities and findings from the 2016 year and
presents a prevention plan, outlining proposed activities for 2017. The goal of the
program for 2017 is to minimize the impact of VBD on human health through region-
wide surveillance and IMM.
West Nile Virus
WNV was first detected in Peel in birds and mosquitoes in 2001. Locally acquired
human illness occurred for the first time in 2002 when 112 residents had laboratory
evidence of WNV infection (55 suspect cases, 20 probable cases and 37 confirmed
cases, including two deaths)1. The goal of the Vector-Borne Disease (VBD) program is
to minimize the impact of WNV with a regional surveillance program for human cases
and WNV activity in adult mosquitoes.
The surveillance program guides VBD activities which include mosquito larvae
reduction, stagnant water site remediation, and risk communication activities. The goal
of the program for 2017 is to minimize the impact of VBD on human health through
region-wide surveillance and IMM.
Surveillance activities continue to indicate that WNV is endemic in Peel. WNV levels
can fluctuate widely from year to year and are highly dependent on weather. In 2016,
the weather was hot and dry. The number of days over 30C in June, July and August
exceeded the previous 10 year average. Table 1 shows the average daily temperature
for 2016 compared to the previous 10 year average. Table 2 shows the number of
rainfall events over 10mm for 2016 compared to the previous 10 year average. In May,
June and July, there were no rainfall events that produced over 10mm of rain, leading to
a significantly drier year than usual.
1 The case definition has changed since 2002. If current human case definitions were used, there would
have been 18 confirmed cases in 2002.
4
Source: Government of Canada, 2016 www.climate.weather.gc.ca
Source: Government of Canada, 2016 www.climate.weather.gc.ca
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Date
Ap
r 05
Ap
r 10
Ap
r 15
Ap
r 20
Ap
r 25
Ap
r 30
Ma
y 0
5
Ma
y 1
0
Ma
y 1
5
Ma
y 2
0
Ma
y 2
5
Ma
y 3
0
Jun
04
Jun
09
Jun
14
Jun
19
Jun
24
Jun
29
Jul 04
Jul 09
Jul 14
Jul 19
Jul 24
Jul 29
Au
g 0
3
Au
g 0
8
Au
g 1
3
Au
g 1
8
Au
g 2
3
Au
g 2
8
Se
p 0
2
Se
p 0
7
Se
p 1
2
Se
p 1
7
Se
p 2
2
Se
p 2
7
Tem
pera
ture
(C
)
Date
Table 1 Average Daily Temperature for 2016 Compared to 2006-2015
2006-2015 Ave 2016
1
2
3
4
5
Total # ofDays - Apr
Total # ofDays - May
Total # ofDays - Jun
Total # ofDays - Jul
Total # ofDays - Aug
Total # ofDays - Sep
3 3
4
3
3 3
2
0 0 0
3
2
Nu
mb
er
of
Days
Month
Table 2 Number of Days with Rainfall Over 10mm by Month Comparing 2006-2015 to 2016
Monthly Ave of # of Days 2006-2015 Monthly # of Days 2016
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Human Case Surveillance
Objective:
To monitor the incidence of human WNV cases in Peel.
The human case surveillance program is intended to identify human cases of WNV in
Peel so Peel Public Health can determine the source of disease and the risk to others.
All probable and confirmed human cases identified by hospitals and physicians are
reported to the local public health department
Peel Public Health staff investigates all suspected, probable and confirmed WNV cases
among residents in Peel, based on case definitions developed by the Ministry of Health
and Long Term Care (MOHLTC). Standardized medical information including
demographics, symptoms, risk factors (such as travel history or having received blood
products) and test results are entered into the MOHLTC’s system called the Integrated
Public Health Information System (iPHIS). Cases that are classified as confirmed or
probable according to provincial case definitions are mapped onto a Geographic
Information System (GIS) according to postal code to track trends and outbreaks. In
2016, there were six confirmed human cases of WNV in Peel Region (Table 3).
Table 3: Number of Human Cases by Municipality (confirmed and probable),
Region of Peel, 2002 – 2016
Year Region of Peel Mississauga Brampton Caledon
2002 112 C-34; P-18; S-46 C-3; P-2; S-8 C-0; P-0; S-1
2014 0 0 0 0
2015 2 C-1 C-1 0
2016 6 C-6 0 0
C-Confirmed, P-Probable, S-Suspected
†In 2002, there were a total of 112 cases with laboratory and/or clinical evidence of WNV infection; 57 cases were classified as probable or confirmed. In subsequent
years, only confirmed cases were reported as a result of changes in disease classifications. If the present day classifications were applied, there would have been 18
confirmed human cases in 2002.
*Data for human cases from 2003-2013 can be found in past technical reports available at: https://www.peelregion.ca/health/vbd/resources/reports.htm#reports
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Comparison with Other Ontario Health Units
As of January 31, 2017, there were 50 confirmed or probable WNV human cases in
Ontario, from Durham Region (2), Haldimand-Norfolk (1), Halton Region (1), Hamilton
Public Health Services (1), Niagara Region (7), Ottawa Public Health (2), Region of
Peel (6), Simcoe Muskoka (1), Toronto (22), Windsor-Essex County (4) and York
Region (3). In 2015, there were 32 human WNV cases in Ontario, in 2014 - 11 and in
2013 - 55.
Comparison with Other Provinces
In 2016, there were a total of 93 human cases in Canada, compared to 76 cases in
2015, 21 cases in 2014 and 115 cases in 2013. In 2016, positive human cases were
found in Alberta (4), Manitoba (20), Ontario (50), Quebec (19), and Saskatchewan (1).
Planned Activities for 2017:
Peel Public Health staff will investigate all suspected, probable and confirmed
cases of WNV report to Peel Public Health.
Peel Public Health will maintain a database and map of all probable and
confirmed cases of WNV.
Peel Public Health will work closely with Public Health Ontario to ensure that
surveillance information is standardized and that personal medical information
remains confidential.
In early summer, Peel Public Health will distribute a Health Professionals Update
to Peel physicians about the importance of immediately reporting all suspected
cases of viral encephalitis and viral meningitis. The update will communicate
information on how to submit appropriate laboratory samples to determine if the
cause is a mosquito-borne virus.
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Adult Mosquito Surveillance Objective:
To monitor numbers, species and locations of adult mosquito populations and to
detect the presence of WNV in the mosquito population.
In 2016, Peel Public Health monitored WNV activity in the local adult mosquito
population from June 19 to October 1 in thirty-one fixed CDC light traps distributed
across the Region: seventeen in the City of Mississauga, nine in the City of Brampton
and five in the Town of Caledon (Map 1). The red dots on Map 1 denote traps from
which positive WNV mosquitoes were collected. In 2016, eighteen traps collected
positive mosquitoes, nine in Mississauga and nine in Brampton.
Peel Public Health sent adult specimens collected in the 31 mosquito traps to GDG
Environnement Lteé. GDG Environnement Lteé provided Peel Public Health with
mosquito identification, and WNV and EEE testing services as part of the monitoring
program. A maximum of two pools for WNV (Culex complex only) were tested per trap
during the first six weeks of the adult surveillance program. Up to four pools of WNV
vector mosquitoes were tested in the remaining 11 weeks in the traps located in
Brampton and Mississauga. Pool sizes contained a maximum of 50 mosquitoes. These
pools were homogenized, extracted and viral tested. The “gold standard” real time RT-
PCR test was used according to the MOHLTC criteria.
The year to year onset and peak of WNV-positive mosquito batches vary. The first
positive trapping event in 2016 occurred during week 28 (July 10 and July 16) in north
Mississauga. The last positive batches in 2016 occurred during week 37 (September 11
to September 17) in north Mississauga and Brampton (Figure 1). Overall the WNV
activity based on the adult mosquito surveillance in 2016 was relatively typical of a
normal year.
In 2016, 43,688 mosquitoes were collected and 25,325 were identified; of those, 10,772
were WNV vectors (Table 4). The most abundant vector species were Aedes vexans
and Culex pipiens/restuans. There were a total of 63 WNV positive mosquito pools, of
these 40 were in Brampton and 23 in Mississauga. The majority of positive pools were
Culex pipiens/restuans with 58 of 63 (92%) testing positive for WNV (Table 5).
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Map 1: Map of Mosquito Trap Location, Region of Peel, 2016
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Figure 1: WNV Positive Mosquito Batches by Week of Collection, 2012-2016
Table 4: West Nile Virus Vector Species Abundance Totals, 2016
Species Specimens
Tested Percentage %
Cx pipiens/restuans 6,398 59
Ae vexans 3,352 31
An. punctipennis 454 4
Oc japonicus 324 3
Oc trivittatus 103 1
Oc triseriatus/hendersoni 92 1
Culex species 22 <1
An. quadrimaculatus 16 <1
Cx salinarius 10 <1
Oc stimulans 1 <1
Total 10,772 100.00 Source: GDG Environnement Lteé: based on PCR data
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Table 5: West Nile Virus Vector Species Testing Pools, Region of Peel, 2016
Species Pools Tested
Specimens Tested
Positive Pools
Cx pipiens/restuans 402 6,398 58
Ae vexans 245 3,352 4
An. punctipennis 143 454 -
Oc japonicus 95 324 1
Oc trivittatus 45 103 -
Oc triseriatus/hendersoni 33 92 -
Culex species 18 22 -
An. quadrimaculatus 8 16 -
Cx salinarius 6 10 -
Oc stimulans 1 1 -
Total 996 10,772 63 Source: GDG Environnement Lteé: based on PCR data Minimum Infection Rate
The minimum infection rate (MIR) is used as an indicator of the prevalence of WNV
transmission intensity and therefore, the risk for human disease. Table 6 shows the
MIR’s for the Culex species by municipality in the Region of Peel in 2016. The overall
MIR in Culex species in the Region of Peel was 9.02 in 2016, which was higher than the
3.39 in 2015.
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Table 6: Minimum Infection Rates* of Culex Species by Municipality, Region of Peel, 2016
Municipality Vector Species
2016 Actual
Number
Tested
2016
Positive
Batches
2016
MIR*
Mississauga
Culex pipiens/restuans
Culex salinarius 1,777 22 12.38
Brampton
Culex pipiens/restuans
Culex salinarius 4,264 36 8.44
Caledon
Culex pipiens/restuans
Culex salinarius 389 0 0.00+
Peel Region
Culex pipiens/restuans
Culex salinarius 6,430 58 9.02
*The Minimum Infection Rate (MIR) is calculated as the number of positive batches of infected mosquitoes of a given species
divided by the total number of mosquitoes of a given vector species that were tested for the presence of the virus, expressed by
1,000
+MIR’s are unreliable when the sample is less than 1,000. Fewer than 1,000 Culex mosquitoes were collected in Caledon so the
MIR could not be accurately calculated.
Planned Activities for 2017:
Peel Public Health will add two new trap locations in Brampton in wards 6 and 9.
These wards do not currently have traps located in them. There will be a total of
33 traps set in the Region of Peel weekly. The additional two traps are being
added to reflect an increase in population and urbanization in Brampton.
From mid-June to early October, Peel Public Health will trap adult mosquitoes at
33 permanent sites throughout the three municipalities. Mosquitoes will be
collected using CDC light traps. Adult mosquitoes will be sent to Peel’s mosquito
laboratory service provider for testing, speciation and viral testing.
Peel Public Health will monitor the prevalence and distribution of new and
invasive mosquito species such as Ochlerotatus japonicus and Aedes albopictus.
Larval Mosquito Surveillance
Objective:
To monitor numbers, species and locations of larval mosquito activity to inform
larval reduction activities.
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Larval surveillance is useful in guiding WNV prevention and reduction activities. It is
used to determine the location, species and population densities of mosquitoes and for
establishing optimal times for implementing larval reduction measures. Potential
breeding sites are identified by referring to breeding site information collected in
previous years and by stagnant water complaints received through the Environmental
Health Contact Centre or the on-line reporting form.
In 2016, staff surveyed a variety of aquatic habitats for the presence of mosquito larvae
from early June to late September, identifying 1,695 potential mosquito breeding sites
on publicly-owned lands across the Region. Culverts (25.8%) and ditches (21.6%)
comprised almost half of the sites with larvae present (Figure 2). Culverts and ditches
are the most difficult sites to achieve successful abatement of mosquito populations
using control measures because of their relative abundance and effectiveness at
holding standing water.
Figure 2: Type of Sites Found to Contain Mosquito Larvae, Region of Peel, 2016
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Species Identification - Larval Analysis
In 2016, VBD staff identified 5,966 mosquito larvae from June to September, a
decrease from the 9,403 larvae identified in 2015. Twelve different species were
identified. The majority (69%) were Culex species - Cx. pipiens/restuans which are key
WNV vectors, higher than the 65% identified in 2015 (Table 7). Aedes vexans, a
confirmed WNV bridge vector in Ontario, accounted for 5% of larvae identified, much
less than the 22% identified in 2015. Oc. japonicus, an invasive species of concern that
is also a WNV vector, accounted for less than one percent of larvae identified.
Table 7: Larval species identified
Planned Activities for 2017:
Peel Public Health will continue to work closely with other agencies to collect and
map information on potential mosquito-breeding habitats.
Peel Public Health will regularly inspect priority breeding sites, identified through
surveillance data gathered from adult mosquito trapping, and refer these sites for
larviciding treatment when warranted.
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Larval Mosquito Reduction
Objective:
To reduce the abundance of adult mosquitoes that can transmit WNV to humans
through the use of Integrated Mosquito Management practices.
The purpose of the larviciding program is to reduce mosquito abundance, especially in
the Culex species. It is more efficient and cost effective to control mosquito populations
by treating mosquito larvae with larvicides than trying to reduce the number of adult
mosquitoes.
Mosquito breeding habitats of importance include roadside catch basins, ditches,
culverts, discarded tires, unused swimming pools, field pools and containers left
outdoors. Surface water breeding sites are many in number and type and can change
from year to year requiring a systematic approach to their surveillance and treatment.
Habitat modification, which includes altering the habitat to eliminate standing water, can
also reduce the potential to breed mosquitoes. In 2016, Peel Public Health staff
continued to investigate complaints and work with municipal departments to pursue all
effective measures to achieve this outcome.
Service Requests
In 2016, the VBD team responded to 310 service requests (Table 8). The greatest
number of service requests were related to backyard catch basins (35%) followed by
swimming pools (30%). In 2015, there were 380 service requests to the VBD team, with
catch basin and swimming pools comprising the majority of complaints.
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Catch Basin Treatment
Catch basin networks are extensive in urban and suburban environments. They retain
a small amount of water and organic matter in the form of sediment that collects in the
sump of the catch basin. The majority of catch basins in Peel have been found to
contain larvae.
The larvicides that will be used in the Region of Peel are Bacillus sphaericus (Bs),
Bacillus thuringiensis var. israelensis (Bti) and methoprene (Altosid®).Methoprene is a
synthetic insect growth regulator which interferes with the development of mosquito
larvae into adults. It has been widely used over a period of many years, and its
effectiveness and environmental impact have been extensively studied and
documented. Bti is a biological pesticide that kills mosquito larvae before they develop
into adults. Bti will be used in surface water breeding sites where impacts on species
other than mosquitoes are more of a concern. B. sphaericus (Bs) provides mosquito
Table 8: COMPLAINT SUMMARY - 2016
Type # of Complaints %age of Complaints
based on Total Complaints
Catch Basin - Backyard 107 34.52%
Catch Basin - Municipal 2 0.65%
Education - Lyme 2 0.65%
Education - Zika 1 0.32%
Education - WNV 5 1.61%
Pond/Wetland - Private 3 0.97%
Pond/Wetland - Public 8 2.58%
Pond - Ornamental 6 1.94%
Pond - Storm Water 1 0.32%
Swimming Pool 92 29.68%
SW - Private Property 23 7.42%
SW - Public Property 8 2.58%
Tick 47 15.16%
WNV Email Notification Request 5 1.61%
Total Complaints 310 100.00%
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control over a period of time is effective in controlling mosquito larvae in high organic
environments like catch basins. Since 2005, Bs has been used in Peel to treat catch
basins that drain directly into sensitive sites as well as some selected surface water
sites.
Three rounds of roadside municipal catch basin larviciding were conducted in 2016.
The municipal catch basins were treated with Altosid® Pellets (the active ingredient
being Methoprene) with the exception of the catch basins located within
Environmentally Sensitive Areas (ESAs) which were treated with VectoLex®2 WSP
(Bacillus sphaericus) by GDG Environnement Lteé under permit by the Ministry of
Environment and Climate Change (MOECC). Non-roadside catch basins were treated
once with a single application of Altosid® Briquets which provide over 90 days of
control. Factors such as catch basin cleaning, new subdivisions, parked vehicles and
construction prevented access to some roadside catch basins and resulted in a
variance in treatments during each round.
In Peel Region in 2016 a total of 302,387 (approximately 100,000 treatments for each
round) roadside catch basins were treated with 210.65 kg of Altosid® Pellets, and 742
catch basins were treated with Vectolex® water soluble pellets (WSP). Altosid® XR
Briquets were applied to 1,442 non-roadside catch basins, including those located in or
along parks, private backyards, daycares, government buildings, social housing
complexes and long-term care facilities.
Surface Water Treatment
Monitoring mosquito larval habitats to assess the presence and abundance of mosquito
larvae was conducted using a standard plastic dipper following the Ministry of
Environment and Climate Change’s (MOECC) sequential sampling method. On each
surveillance visit, the standing water site was given a pool rating based on the total
number of larvae observed. Larval samples were also collected and identified by Peel
Public Health staff. If vectors were identified, the surface water site was referred to
GDG Environnement Lteé for treatment from May 29 to October 1.
There were 553 surface water treatments applied in 2016 (Table 9), compared to 619
treatments in 2015. GDG Environnement Lteé staff reported an additional 552 surface
water visits did not result in treatment as the sites were dry, had low larvae counts or
vector species were not present at the time of their site visits.
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Table 9: Number of Surface Water Sites Treated, Region of Peel, 2016
Month
Number of visits
Number of sites
treated
Qty. of
vectobac
applied (L)
Treated area
(ha)
June
July August
September
293
287
382
143
121
154
198
80
0.0657
0.0635
0.1026
0.0473
0.07
0.06
0.10
0.05 Total 1105 553 0.2791 0.29
Source: GDG Environnement Lteé, 2016
Stormwater Management Ponds
Historical larval surveillance data has revealed that the majority of stormwater
management ponds (SWMP) generally do not support significant numbers of mosquito
larvae. In most of the SWMPs surveyed, where there is larval activity, it is limited to
areas of shallow shorelines with dense vegetation, where litter has accumulated, or in
culvert outflows. These conditions create a favourable environment for mosquito
breeding by providing the mosquito larvae protection from the environment (wind,
waves, sun), and protection from predators such as frogs, fish, and other insects.
In 2016, in Mississauga 23 SWMPs were surveyed that had consistently showed larval
activity in previous years. Ninety one percent had mosquito larval activity; 83% of those
sites were referred for treatment to GDG Environnement Ltee. In 2016, site visits of
Brampton SWMPs only occurred on request or on a complaint basis.
Planned Activities for 2017:
Peel Public Health will encourage habitat modification (including changing the
physical environment such as improving drainage or introducing predators) to
make the environment less hospitable for mosquito breeding.
Where Culex mosquito breeding cannot be effectively reduced by other means,
larvicides will be employed. The larvicides that will be used in the Region of Peel
are Bacillus sphaericus (Bs), Bacillus thuringiensis var. israelensis (Bti) and
methoprene (Altosid®).
Peel Public Health will continue to work closely with staff from the local
municipalities when investigating stagnant water complaints. Sites located on
public property will be investigated by the Peel VBD team. Stagnant water issues
18
on private property will be addressed by the local by-law enforcement staff under
the existing municipal property standard by-laws. In circumstances in which the
private property owner does not comply with the municipal by-law Orders, Peel
Public Health will investigate and, if warranted, issue a notice or Order under
public health legislation.
There will be three scheduled rounds of methoprene applications to the
approximately 100,000 roadside catch basins in the Region of Peel; a fourth
round may be considered if high levels of WNV activity are evident. Peel Public
Health will work closely with the larviciding contractor to ensure larval
surveillance findings are used to strategically time the three applications.
The Medical Officer of Health will issue an Order to each local municipality
directing them to assist in and facilitate the application of larvicides to catch
basins.
Municipal roadside ditches that hold water for longer than seven days will be
referred to the local roads departments for assessment and remediation. Ditches
containing mosquito larvae will be treated with Bti or Bacillus sphaericus.
Field staff will monitor SWMPs in Mississauga that have a history of larval
mosquito activity and conduct a risk assessment of the new SWMPs in Brampton
to determine the need for surveillance of these ponds.
If significant mosquito breeding is found at a storm water management pond site,
Bti or Bs will be used as part of an IMM approach.
Peel Public Health will conduct research on what attributes of a SWMP contribute
to support the development of WNV vectors. This information will be used to
prioritize surveillance activities at SWMPs across the Region of Peel.
Peel Public Health will work with municipal departments to ensure that existing
sanitation and waste removal on public property (including green areas such as
parks, cemeteries, golf courses) places emphasis on removing garbage that
promotes mosquito breeding (e.g. tires, pails, etc).
Peel Public Health will work with other agencies to identify areas of stagnant
water associated with surface grading problems, road construction, clogged
sewers and catch basins and obstructed waterways that are serving as
mosquito-breeding habitats. These areas will be assessed on a site specific
basis as they are identified and may be treated with larvicide. Remediation will
be performed if possible.
19
Backyard catch basins will only be treated upon the request of the home owner.
A consent form must be signed by the home owner prior to treatment.
Methoprene will be the larvicide used to treat backyard catch basins.
In catch basins draining directly into environmentally sensitive areas, the
biological larvicide Bacillus sphaericus will be used.
Pesticide Effects and Monitoring
Objective:
To identify any unplanned impacts of pesticides used in mosquito control on
human or ecosystem health.
Environmentally Sensitive Areas (ESA)
There are two circumstances when a Sensitive Area and Species Protocol are required
by the MOECC in order to obtain a permit and apply a larvicide.
The first situation occurs when a catch basin is either located within an ESA or it is
known to be the last catch basin before an outfall into an ESA. In Peel, there were 530
municipal catch basins that met one of these criteria. VectoLex®WSP was used to
control mosquito larvae in ESA catch basins.
The second situation occurs when a standing water site falls within an ESA. In Peel,
there are several standing water sites that meet this criterion including multiple sites
within Rattray Marsh, Cawthra Woods, Heartlake Wetland Complex, Credit River
Wetland (O’Neil Court Storm Water Management Pond), Credit River Marsh and Lorne
Park Prairie.
Permits from the Ontario Ministry of Natural Resources (MNR) and a special wetlands
permit were obtained to allow for larviciding within specific ESA’s in Peel. Six ESA’s
were noted in the permit: Rattray Marsh, Cawthra Woods, Heartlake Wetland Complex,
Credit River Wetland (O’Neil Court Storm Water Management Pond), Credit River
Marsh and Lorne Park Prairie. ESA’s are defined by the MOECC and spatial location
data is obtained from the MNR.
Pesticide Effects Surveillance
In 2016, pesticide effects surveillance was included in the WNV component of the
Vector-Borne Disease plan. As in previous years, Peel Public Health continued to work
with other municipalities, conservation authorities and the MOECC to ensure our
larviciding program did not negatively impact the ecosystem. Peel Public Health also
20
used larvicide products that have been identified as having the least environmental
impact. Staff from the VBD team also conducted field inspections to verify that the
service provider contracted to apply larviciding in Peel was doing so in accordance with
MOECC regulations.
Efficacy and Quality Assurance Monitoring
Peel Public Health conducted quality assurance monitoring of roadside catch basins
during all three rounds of treatment. VBD students were assigned map zones and
noted the catch basins that did not have a coloured paint dot associated with the latest
application round. GDG Environnement Lteé was provided a list of the missed catch
basins which were to be revisited within 24 hours of notification.
Peel Public Health also conducts catch basin methoprene efficacy tests each year. The
VBD team follows the post-larviciding monitoring for methoprene efficacy protocol noted
in the MOECC Permit Applicant Guide for Municipalities and Health Units: Controlling
Mosquito Larvae for Prevention and/or Control of West Nile Virus.
VBD staff collects mosquito pupae and roadside catch basin water following each
application round of the pellets from a small number of catch basins. The pupae were
kept in jars covered with mesh lids and observed daily to see if viable adults
successfully emerged over a period of 4 days. The number of dead pupae, dead adults
and live adults are counted. In 2016, 25 pupae were collected and 8 viable adults
emerged, resulting in 64% efficacy, which is a lower efficacy rate than the 81% recorded
in 2015. This is likely due to the extremely hot weather, as sun degrades the pesticide’s
effectiveness.
Planned Activities for 2017:
Peel Public Health will conduct field inspections to verify that the service provider
contracted to conduct larviciding is applying the larvicides in accordance with
MOECC regulations.
Peel Public Health will continue to use larviciding products that have been
identified as having the least environmental impact.
B. sphaericus (Bs) will be used in Peel to treat catch basins that drain directly
into sensitive sites as well as some selected surface water sites.
Peel Public Health will conduct catch basin efficacy tests during each round of
larviciding treatment to determine larviciding efficacy.
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Risk Assessment and Adulticiding
Objectives:
To monitor the level of risk from WNV in the Region of Peel that will be used to
inform decisions of when increased public education or adult mosquito reduction
techniques are needed.
To reduce the abundance of adult mosquitoes in areas of elevated risk to human
health from WNV through the judicious use of pesticides.
In 2016, from mid-June to early October (week 25-40), a weekly risk assessment was
conducted based on surveillance information collected during that week to identify the
relative risk of human infection in Peel Region. Various surveillance factors that
influence the risk of WNV infection were evaluated. The factors included were:
Seasonal temperatures
Adult mosquito vector abundance
Virus isolation rate in vector mosquito species
Human cases of WNV
Local WNV activity (equine, mosquito)
Time of year
WNV activity in proximal urban or suburban regions
Each surveillance factor was assigned a weighted score based on the observations of
the previous week. The WNV Mosquito Adulticiding Risk Assessment form was
completed weekly. When the risk assessment level exceeded a value of three, a
decision tree process to consider additional action was invoked.
One possible additional action is adulticiding. Adulticiding is the application of chemicals
to kill adult mosquitoes by ground or aerial application. Adulticiding would only be
considered in Peel if there was a significant risk to human health. Adulticides are
typically applied as an Ultra-Low-Volume (ULV) spray, where small amounts of
insecticide are dispersed either by truck-mounted equipment or from fixed-wing or rotary
aircraft. For effective adult mosquito reduction, the fine ULV droplets must drift through
the habitat and come in contact with flying mosquitoes. Adulticiding is the least efficient
mosquito control technique since adult mosquitoes are widely dispersed and the
pesticide has to make contact with the mosquito in order to kill it. Nevertheless, targeted
adulticiding, based on surveillance data, is an extremely important part of any IMM
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program. If an outbreak of human cases is occurring or imminent, it means that large
numbers of WNV infected adult mosquitoes are likely present. This risk can only be
mitigated in the short term through adult mosquito reduction.
The possibility of adulticiding is considered when the risk level exceeded a value of four.
In 2016, the risk assessment level was 4.2 in mid-august.
Planned activities for 2017:
Peel Public Health will conduct an evaluation of the WNV risk assessment tool.
Adulticiding decisions will be made on a case-by-case basis according to the
level of human risk of WNV in consultation with the MOHLTC and Public Health
Ontario.
If necessary, Peel Public Health would use malathion for adult mosquito control.
Peel Public Health will annually review the availability, health impact and
effectiveness information of pesticides. Any product will be applied in
compliance with local, provincial and federal laws and regulations.
The public would be notified of adulticide locations and schedules in advance,
which will allow sufficient time to take any necessary precautions to reduce
pesticide exposure (see Public Education and Community Outreach).
Information would be released at least 48 hours in advance through the media,
the Peel Public Health website, Environmental Health Customer Contact Centre,
pertinent municipal and community organizations and the Ontario Regional
Poison Control Centre in accordance with MOE requirements.
Hospitals would be notified regarding the adulticiding schedule. Information on
the pesticide that will be used will be provided to the public, physicians and other
health care providers.
Elected officials would be notified immediately once the Medical Officer of Health
has made the decision to adulticide.
Peel Public Health would monitor and assess control activities for any potential
environmental and health effects through several measures which may include
pre- and post-spray environmental sampling and addressing pesticide exposure
complaints received by Peel Public Health.
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Public Education and Community Outreach Activities
Objectives:
To inform Peel residents about WNV and the measures that they can take to
prevent human illness, including mosquito breeding site reduction and personal
protective measures.
To provide clear, accurate and timely communication about the status of WNV in
Peel, to all target groups.
Peel Public Health has developed various educational resources about personal
protective measures and individual and household activities that prevent or discourage
the breeding of mosquitoes. The resources include flyers, fact sheets, posters and
newspaper advertisements. These resource materials are made available on the
Region of Peel VBD website http://www.peelregion.ca/health/vbd. The website is also
used to post WNV surveillance results, update larviciding activities and provide the
public with access to the VBD Prevention Plan.
As in previous years, educational materials on WNV were mailed to the following
groups: long-term care facilities, child care centres, garden centres, golf courses,
horticultural societies and multicultural associations. The only newspaper advertisement
in 2016 was the larviciding application notice which is required by the MOECC.
In 2016, residents and organizations were encouraged to sign up at
http://www.peelregion.ca/health/vbd to receive email notification of positive WNV activity
in Peel. In addition, the electronic WNV notification database for institutions and for
parks and recreation facilities that were located within a one kilometre range of each of
the 31 fixed mosquito trap sites continued to be utilized. An email was sent to
institutions and to parks and recreation facilities when a positive mosquito batch was
reported in their area.
Planned Activities for 2017:
A report to Council on the planned VBD activities for 2017 will be brought forward in
May. It will focus on West Nile Virus and Lyme disease but also address other
reportable and non-reportable vector borne diseases, such as Eastern Equine
Encephalitis, malaria and Zika virus.
Presentations on the West Nile Virus program will be made at Regional and area
municipal Councils, if requested. Additional presentations to the general public may
be conducted if the risk of WNV infection increases.
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To assist partner agencies to respond to public inquiries with consistent information
on WNV through information available on the Region of Peel VBD website.
An overview of the 2017 VBD program including WNV activities is available for
Councillor’s newsletters upon request.
Peel Public Health’s 2017 VBD Plan will be available on the VBD website as will fact
sheets on topics such as personal protection measures, reduction of mosquito
breeding sites, larviciding, and many others. The website will be regularly updated
with information on the status of WNV activity in Peel, with the catch basin larviciding
schedule. An on-line stagnant water reporting form will continue to be available.
An electronic mailout providing educational materials on WNV will be sent to the
following groups: long-term care facilities, child care centres, garden centres, golf
courses, horticultural societies and multicultural associations.
Newspaper notices will be used to meet the MOECC regulatory requirements for
public notification of the use of larvicides.
Radio messages, sign boards and website messaging will be considered if
surveillance activities indicate significantly high levels of WNV activity in Peel.
Media relation activities will include news releases to the local media, interviews with
the MOH and AMOH, if requested, and media briefings and/or news conferences, if
required.
Local health care providers will be notified about the status of WNV activity in Peel
through a faxed Health Professionals Update. Early in the WNV season, information
on WNV signs and symptoms, laboratory diagnosis, treatment, patient counselling
and human case reporting to Peel Public Health will be provided. Additional
notification will be provided on the status of WNV should the situation progress or
change.
Grand rounds on WNV will be conducted at the three hospitals located in Peel in
May.
WNV updates will be distributed by email when there is positive WNV activity in
Peel. The WNV updates will be sent to Regional Councillors, local municipalities,
neighbouring health units, conservation authorities, the media, and other
stakeholders. The update will also be posted on the Region of Peel VBD website.
Councillors will be notified by email of any WNV activity in their ward.
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A contingency communication plan has been developed in the event of adulticiding.
It includes tactics such as public meetings, advertising, direct mail, news
conferences and briefings, media relations, news releases and website updates to
inform the public about adulticiding treatment areas and schedules.
We encourage interested residents or organizations to sign up at peel-bugbite.ca to
receive email notification of positive WNV activity in Peel.
An electronic WNV notification database for institutions and for parks and recreation
facilities that are located within a 1 kilometre range of each of the 33 fixed mosquito
trap sites has been developed. An email will be sent to them when a positive
mosquito batch is reported in their area.
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Lyme Disease
Lyme disease is passed to humans through the bite of certain types of ticks that are
infected with a bacterium called Borrelia burgdorferi. In Ontario, the disease is spread
by the black-legged tick, sometimes called the deer tick. There are areas in which the
bacteria is endemic, meaning the disease is well established and present more or less
continually in that region.
Each year Public Health Ontario identifies Lyme disease risk areas in the province. Risk
areas identify a 20km radius from where blacklegged tick activity was found through
drag sampling. The risk area closest to Peel is the Rouge Valley. Peel does not
currently have a designated risk area. However, ticks can be spread by migratory birds,
in particular, songbirds that feed off the ground, so there is the potential for new
populations of ticks to be spread across the province. Therefore, one does not
necessarily have to be in a high-risk area to be at risk of encountering ticks and
disease.
There are concerns that changes of climatic conditions such as warmer seasons could
lead to conditions that are favourable for the establishment of blacklegged tick
populations in many parts of the province. The expansion of the blacklegged tick
population would likely result in an increase in human cases in the province.
Human Cases and Surveillance
Objective:
To monitor the incidents of human Lyme disease cases in Peel.
Lyme disease is a reportable disease in Ontario. As a result, Peel Public Health staff
investigates all potential cases of Lyme disease among residents in Peel. In 2016, four
confirmed Lyme disease cases were investigated in Peel residents (Table 10); these
cases were all acquired during travel outside of the Region of Peel.
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Table 10: Lyme Disease Cases in the Region of Peel, 2001 – 2016
Year Confirmed
Cases
2001 1
2002 2
2003 2
2004 3
2005 3
2006 8
2007 6
2008 11
2009 6
2010 2
2011 3
2012 7
2013 5*
2014 4*
2015 2
2016 4
*One additional case in 2013 and 2014 were added to previous counts. These cases were investigated in 2016 but exposure and
onset of symptoms occurred in 2013 and 2014 respectively.
Planned activities for 2017:
Peel Public Health staff will continue to investigate all potential cases of Lyme
disease among residents in Peel.
If there is evidence of a confirmed case of Lyme disease that has been acquired
locally, then active surveillance including tick dragging will be undertaken.
Local health care providers will be notified about the status of Lyme disease activity
in Peel through a faxed Health Professionals Update. The update will include
information on symptoms, laboratory diagnosis, treatment and human case reporting
to Peel Public Health.
Grand rounds on Lyme disease will be conducted at the three hospitals located in
Peel in May.
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Tick Surveillance
Objective:
To monitor the number, species and locations of ticks in Peel to detect the
presence of blacklegged ticks and Lyme disease.
Active tick surveillance means collecting ticks in their natural habitat, while passive
surveillance means studying ticks submitted to Peel Public Health by Peel residents. In
2016, Peel Public Health continued passive tick surveillance. A total of 37 tick samples
were submitted to Peel Public Health. Ticks were submitted to the Central Public Health
Laboratory (CPHL) in Toronto for species confirmation. The breakdown of the 37 ticks is
as follows:
11 blacklegged ticks (6 acquired in Peel), sent to the Public Health Agency of
Canada’s (PHAC) National Microbiology Laboratory in Winnipeg for Lyme
disease testing.
o 11 were negative for Borrelia burgdoferi; including five acquired from Peel.
22 Dermacentor variabilis (dog tick)
3 Ixodes marxei (squirrel tick)
1 Ixodes ricinus
In 2016, Peel Public Health conducted active tick surveillance at three sites in
Mississauga. The sites were identified through the passive tick surveillance system as
areas that could contain blacklegged ticks. The tick dragging sessions did not identify
any further ticks.
Planned Activities for 2017:
If an established tick population is identified or there is evidence of a tick confirmed
case of Lyme disease that was locally acquired, then active surveillance including
tick dragging will be undertaken.
Peel Public Health will work with Public Health Ontario to identify and establish a risk
area if blacklegged tick activity was identified through active tick surveillance in the
Region of Peel.
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Public Education Activities
Objective:
To inform Peel residents about Lyme disease activity and the measures they can
take to prevent human illness.
In 2016, a Health Professionals Update on Lyme disease and a Lyme disease algorithm
were distributed to physicians in Peel. The Health Professionals Update can be found
at: http://www.peelregion.ca/health/professionals/tools/updates2016.htm.
Grand Rounds on Lyme disease were carried out in May at the three hospitals located
in Peel.
Planned Activities for 2017:
Lyme disease information is available for Councillor newsletters upon request.
The Lyme disease algorithm is being evaluated with physicians contacted by the
VBD team during a human case investigation.
Educational materials on Lyme disease are available to the public through the
website or by request.
A Lyme disease newspaper advertisement has been developed. The use of these
advertisements in 2017 will be considered if surveillance activities indicate a
significant increase in Lyme disease activity in Peel.
A report to Council will provide information about the 2017 VBD Plan and will include
an overview of the Lyme disease component of the plan.
Eastern Equine Encephalitis
Eastern Equine Encephalitis, commonly referred to as EEE, is a viral disease of wild
birds that is transmitted to horses and humans by mosquitoes. Of the North American
mosquito-borne diseases, EEE appears to be the most severe human pathogen;
approximately 33% of people who develop EEE die of the disease and many survivors
have long-term health effects.
In Ontario, outbreaks of EEE have occurred sporadically among horses, but no human
cases have ever been confirmed. In 2016, there was no EEE positive mosquito pools
reported in Ontario; however, there were two equine cases reported one each from
Toronto and Middlesex-London (data as of November 25, 2016).
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Adult mosquito surveillance conducted over the last several years has found the key
zoonotic species for EEE, Culiseta melanura, to be present in Peel but in very low
numbers. In 2016, Peel Public Health continued to monitor the prevalence and
distribution of Cs. melanura using the region-wide adult mosquito CDC light trap
network. In 2016, no Cs. melanura were found in the CDC light traps, compared to two
in 2015.
Planned Activities for 2017:
Peel Health will rely on adult and larval mosquito surveillance data in decision-
making about EEE, public education and mosquito reduction activities.
Other Vector-Borne Diseases of Interest
Reportable Diseases
Malaria, dengue hemorrhagic fever and yellow fever are life-threatening diseases
that are transmitted to people through the bite of infected female Aedes and
Anopheles species of mosquitoes. These diseases must be reported to the local
health unit as reportable diseases under the Ontario Health Protection and Promotion
Act.
In Peel, the occurrence of these diseases are all travel related. In 2016, Peel Public
Health investigated 38 cases of malaria and one case of yellow fever. No cases of
dengue hemorrhagic fever were reported.
Planned Activities for 2017:
In 2017, Peel Public Health will investigate all reports of malaria, dengue
hemorrhagic fever and yellow fever, among Peel residents to determine the
source of the mosquito bite that caused the illness and to provide educational
information.
Non-Reportable Diseases
Both Chikungunya and Zika virus are transmitted by a mosquito-borne virus spread by
the Aedes aegypti and Aedes albopictus mosquitoes. These mosquitoes are not
established in Canada and are not well-suited to cool climates. These diseases are not
reportable in Canada.
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Travel-related cases of Chikungunya and Zika virus in Canada have occurred due to
transmission in the Caribbean and Central and South America. There is no vaccine for
either Chikungunya or Zika virus. Both can be prevented by preventing mosquito bites.
Peel Public Health monitors information on chikungunya and Zika virus and provides
information to physicians and the public as it becomes available. In 2016 Peel Public
Health created 5 Health Professionals Updates on Zika virus, one presentation for
Grand Rounds, one report to Council and created a website for the public on Zika virus
(https://www.peelregion.ca/health/topics/zika-virus/index.htm).
Planned Activities for 2017:
Peel Public Health will continue to monitor information on Chikungunya, Zika virus
and other emerging VBDs of interest and will provide information to physicians and
the public as it becomes available.
Conclusion
Surveillance activities continue to indicate that WNV is endemic in Peel and it is
reasonable to assume that the virus will return to Peel at some level in 2017. Peel
Public Health will continue to conduct surveillance, public education and larval mosquito
reduction activities as these are essential WNV program components in a jurisdiction
where WNV has been detected in a previous season.
Peel Public Health will continue public and physician education on Lyme disease
symptoms, testing and prevention activities in 2017. In addition, if an established tick
population is identified or there is evidence of a confirmed case of locally acquired Lyme
disease, then active surveillance including tick dragging will be undertaken.
In 2017, Peel Public Health will also continue to monitor the prevalence and distribution
of EEE and Zika vector mosquitoes by using the regional mosquito trapping network.
