Download Weekly West Nile Virus (WNV) Surveillance Bulletin October 2 to

Communicable Disease
Surveillance Unit
West Nile Virus
Surveillance 2016
Weekly West Nile Virus (WNV) Surveillance Bulletin
October 2 to October 8, 2016
Overview of West Nile Virus (WNV) Activity in Toronto:
October 2 to October 8, 2016*
Indicator
Description of activity:
October 2 to 8, 2016**
No human cases of WNV
were reported this week.
Description of activity:
2016 Year to date
Twenty-two cases have been
reported for 2016 to date (19
confirmed and 3 probable).
Hospitalizations and deaths
There were no
hospitalizations or deaths
due to West Nile virus this
week.
Of the 22 reported cases, 14 (64%)
have been hospitalized, and three
deaths have been reported.
Positive mosquito pools†
Mosquito pool testing has
ended for the season.
In total, 38 mosquito pools have
tested positive for WNV.
Overall
WNV activity in Toronto for this week was lower than the
activity in the previous week.
Reported cases
* For more information on WNV activity in Toronto, including fact sheets, larviciding updates, and prevention strategies, please visit
http://www.toronto.ca/health/westnile/index.htm
**
These terms may not reflect significant changes, but describe overall observed trends.
†
Includes enzootic and non-enzootic mosquito pools.
Table 1. Number of new WNV illness human case reports* by classification and positive
mosquito pools for October 2 to October 8, 2016, compared to the cumulative number of
reports for 2002 and 2012**. Toronto.
Classification
Confirmed
Probable
Total
Positive pools
October 2 to 8, 2016
0
0
0
0
2016 YTD†
19
3
22
38
2012 YTD
80
13
93
100
2002 YTD
129
31
160
168
Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information
System (iPHIS) extracted [12/10/2016].
*As indicated by date of entry into iPHIS.
**As the number of WNV cases reported to TPH varies from year to year, historical averages are not meaningful for
comparison. Peak activity occurred in 2002 and 2012 - those data are presented for comparison.
†
YTD = Year to date. Counts include cases that travelled outside of Toronto during the incubation period of their disease.
Diagnosis status is based on provincial case definitions as described in the Infectious Diseases Protocol, 2009.
Weekly WNV Surveillance Bulletin
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Communicable Disease
Surveillance Unit
West Nile Virus
Surveillance 2016
Figure 1a. Number of reported WNV illness human cases (confirmed and probable) by case defining
symptomatology by episode week. Toronto, June 5 to October 8, 2016.
6
Asymptomatic infection
Non-neurological syndrome
5
Neurological syndrome
Number of reported cases
4
3
2
1
0
Episode week
Source: Ontario Ministry of Healthand Long-Term Care, integrated Public health Information system (iPHIS), extracted [12/10/2016].
Data are provisional and are subject to changes and revisions.
Figure 1b. Number of reported WNV illness human cases (confirmed and probable) by case defining
symptomatology by reported week. Toronto, June 5 to October 8, 2016.
9
8
Neurological syndrome
Non-neurological syndrome
7
Asymptomatic infection
Number of reported cases
6
5
4
3
2
1
0
Reported week
Source: Ontario Ministry of Health and Long-Term Care, integrated Public health Information system (iPHIS), extracted [12/10/2016].
Data are provisional and are subject to changes and revisions.
Weekly WNV Surveillance Bulletin
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Communicable Disease
Surveillance Unit
West Nile Virus
Surveillance 2016
Table 2. Hospitalizations and deaths among reported human cases of WNV illness by age and gender. Toronto,
January 1, 2016 to October 8, 2016 compared to 2002 and 2012* Year-to-date (YTD), and demographic
characteristics of 2016 YTD cases.
Number of cases
Hospitalized
Deceased**
All other cases
Total
Age in years
2016 YTD
2012 YTD
2002 YTD
14
3
8
22
34
1
59
93
81
10
79
160
Median (min, max)
65
87
58
62
(27 -- 89)
(85 -- 89)
(31 -- 66)
(27 -- 89)
Gender
Female
Male
9
3
5
14
5
0
3
8
Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iPHIS), extracted
[12/10/2016].
*As the number of WNV cases reported to TPH varies from year to year, historical averages are not meaningful for comparison. Peak activity occurred in
2002 and 2012 - those data are presented for comparison.
**Deceased cases who were hospitalized are also counted in the "Hospitalized" cases. Only deceased cases where WNV is indicated as a cause of death on
the death certificate are included.
Data are provisional and are subject to changes and revisions.
For additional WNV information visit:
Toronto Public Health, Vectorborne Diseases Program
Public Health Ontario: Vector-borne Disease Surveillance Reports
Ontario Ministry of Health and Long-Term Care: Infectious Diseases Protocol 2009 and Case Definitions
Public Health Agency of Canada
Weekly WNV Surveillance Bulletin
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