West Nile Virus national surveillance report: July 15 - 21, 2018

Organization: Public Health Agency of Canada

Published: August 1, 2018

Related Topics

• West Nile Virus

West Nile Virus - Week 29 2018

Canada

Human

As of July 21, 2018, the Public Health Agency of Canada has been informed of two clinical (confirmed or probable) cases of West Nile virus (WNV) reported by Ontario. One case was related to travel outside of Canada and the other was locally acquired. Clinically, one case (50%) has been classified as WNV neurological syndrome and one case (50%) is unspecified. No deaths have been reported.

Mosquito

To date (week 29), the PHAC has been notified of 5,642 mosquito pools tested for WNV: 323 in Saskatchewan, 962 in Manitoba, 3,784 in Ontario, and 573 in Québec. Of these, fifty-six positive mosquito pools were found: four in Saskatchewan (Moist Mixed Grassland/Aspen Parkland [4]), forty in Manitoba (Winnipeg [11], Interlake-Eastern [9], Prairie Mountain [7], and Southern [13]) and twelve in Ontario (Halton Region [1], Peel Region [1], Windsor-Essex County [7] and York Region [3]).

Wild Bird

As of week 29, a total of twenty-six dead wild birds have been tested for WNV by the Canadian Wildlife Health Cooperative (CWHC) and Manitoba Agriculture: one in Alberta, four in Saskatchewan, three in Manitoba, twelve in Ontario, five in Québec, and one in Nova Scotia. Of these, nine dead wild birds were positive for WNV: three in Manitoba (Winnipeg Regional Health [3]), two in Quebec (Estrie [2]) and four in Ontario (Wellington-Dufferin-Guelph [1], Middlesex-London [2] and Southwestern Public Health [1]).

Equine

The Canadian Food Inspection Agency (CFIA) has not reported domestic animals tested positive for WNV, since the start of the 2018 WNV season.

United States and U.S. territories

As of July 24, thirty-nine human cases of WNV have been reported to the US Centers for Disease Control and Prevention (CDC). Of these, twenty-three (59%) were classified as neuroinvasive disease and sixteen (41%) as non-neuroinvasive disease. One death has been reported. In addition, twelve presumptive viremic blood donors have been identified.

Europe and Neighboring Countries

As of July 19, forty-eight human cases of West Nile fever have been reported to the European Centre for Disease Prevention and Control in the following countries: Serbia (29), Greece (12), Italy (4), Romania (2), and Hungary (1). No deaths have been reported.

Weekly updates: 2018 West Nile fever transmission season

Other Mosquito-borne Diseases - Week 29 2018

Canada

Eastern Equine Encephalitis virus

No human cases of Eastern Equine Encephalitis virus (EEEV) have been reported to the PHAC, since the 2018 season.

California Serogroup virus

In surveillance week 29, no human cases/exposures of California serogroup virus were diagnosed by the National Microbiology Laboratory in the Public Health Agency of Canada.

Figure and tables

Figure 1 - Text description

Map showing geographic distribution of human cases of West Nile virus (WNV) in Canada.

As of July 21, 2018, one human case associated with WNV in Canada has been reported to the Public Health Agency of Canada (PHAC).

Figure 2 note ±: WNV clinical cases and asymptomatic infections are grouped by report week, based on episode date. Episode date could include one of the following: onset date, diagnosis date, lab sample date or reporting date.

Figure 2 - Text description

As of week 29, ending July 21, 2018, there is one human clinical cases and asymptomatic infections associated with WNV in Canada.

Table showing human clinical cases and asymptomatic infections associated with WNV in Canada, by province or territory and by week monitoring, dated July 21, 2018

Province / Territory	Report Weekfigure 2 table note ±																									Total
	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47
British Columbia	0	0	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Alberta	0	0	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Manitoba	0	0	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Ontario	0	0	0	0	0	1	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Québec	0	0	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Total	0	0	0	0	0	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
'-' = Not available. Figure 2 table notes Figure 2 table note ± WNV clinical cases and asymptomatic infections are grouped by report week, based on episode date. Episode date could include one of the following: onset date, diagnosis date, lab sample date or reporting date. Return to figure 2 table note ± referrer

Figure 3 note *: WNV clinical cases and asymptomatic infections are grouped by report week, based on episode date. Episode date could include one of the following: onset date, diagnosis date, lab sample date or reporting date.

Figure 3 - Text description

Table showing WNV human clinical cases and asymptomatic infections in Canada, by report week for selected years

Year	Report Weekfigure 3 table note *																									Total
	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47
2018	0	0	0	0	0	1	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
2017	0	0	1	0	1	1	7	3	8	10	26	31	31	27	13	16	7	8	4	1	1	3	0	0	0	200
2016	0	1	0	0	0	0	0	1	5	5	14	11	16	12	9	6	15	5	0	0	3	1	0	1	0	105
2014	0	0	0	0	0	0	1	0	0	0	4	3	5	6	1	1	0	0	1	0	0	0	0	0	0	22
2012	1	0	0	0	3	5	11	16	27	53	63	57	43	43	45	24	30	14	9	5	1	0	0	0	0	450
2007	2	2	3	4	11	35	36	72	139	424	471	443	287	182	116	71	30	18	10	11	5	4	2	0	0	2,378
2003	0	0	0	1	1	1	5	11	9	27	66	249	323	324	178	107	82	37	14	8	4	3	0	0	0	1,450
'-' = Not available. Figure 3 table notes Figure 3 table note * WNV clinical cases and asymptomatic infections are grouped by report week, based on episode date. Episode date could include one of the following: onset date, diagnosis date, lab sample date or reporting date. Return to figure 3 table note * referrer

Table 1: WNV human clinical cases and asymptomatic infections in Canada by reported weeks and year to date, 2018

Province/Territory	Clinical Cases			Total clinical casestable 1 note 1	Total travel-related casestable 1 note 2	Total asymptomatic infectionstable 1 note 3
	Neurological syndrome	Non-neurological syndrome	Unclassified/ Unspecified
Week 29: July 15 to July 21, 2018
Newfoundland and Labrador	0	0	0	0	0	0
Prince Edward Island	0	0	0	0	0	0
Nova Scotia	0	0	0	0	0	0
New Brunswick	0	0	0	0	0	0
Québec	0	0	0	0	0	0
Ontario	1	0	1	2	1	0
Manitoba	0	0	0	0	0	0
Saskatchewantable 1 note 4	0	-	-	-	-	-
Alberta	0	0	0	0	0	0
British Columbia	0	0	0	0	0	0
Yukon Territory	0	0	0	0	0	0
Northwest Territory	0	0	0	0	0	0
Nunavut	0	0	0	0	0	0
Total	1	0	1	2	1	0
Year to date: January 1 to July 21, 2018
Newfoundland and Labrador	0	0	0	0	0	0
Prince Edward Island	0	0	0	0	0	0
Nova Scotia	0	0	0	0	0	0
New Brunswick	0	0	0	0	0	0
Québec	0	0	0	0	0	0
Ontario	1	0	1	2	1	0
Manitoba	0	0	0	0	0	0
Saskatchewantable 1 note 4	0	-	-	-	-	-
Alberta	0	0	0	0	0	0
British Columbia	0	0	0	0	0	0
Yukon Territory	0	0	0	0	0	0
Northwest Territory	0	0	0	0	0	0
Nunavut	0	0	0	0	0	0
Total	1	0	1	2	1	0
'-' = Not available. Table 1 notes Table 1 note 1 Total clinical cases are the sum of confirmed and probable: WNV neurological and non-neurological syndromes, along with any unclassified or unspecified cases. Return to table 1 note 1 referrer Table 1 note 2 Likely related to travel outside the Province/Territory. These cases are included in either the total clinical cases or WNV asymptomatic infections. Return to table 1 note 2 referrer Table 1 note 3 Satisfies WNV diagnostic test criteria in the absence of clinical criteria. This category could include asymptomatic blood donors whose blood is screened using a nucleic acid amplification test, by blood operators (i.e. Canadian Blood Services or Hema-Quebec) and is subsequently brought to the attention of public health officials. Blood operators in Canada perform a supplementary WNV specific nucleic acid amplification test following any positive donor screen test result. Return to table 1 note 3 referrer Table 1 note 4 Saskatchewan provides counts of WNV neurological syndrome cases only. Return to table 1 note 4 referrer

Table 2: WNV mosquito surveillance^{table 2 note *} in Canada, as of July 21, 2018

Province / Territory	Number of positive mosquito pools	Number of mosquito pools tested	Percentage of positive mosquito pools (%)
Saskatchewan	4	323	1.24
Manitoba	40	962	4.15
Ontario	12	3,784	0.32
Québec	0	573	0.00
Total	56	5,642	0.99
Table 2 notes Table 2 note 1 Mosquito surveillance data is reported by the following four provinces: Quebec, Ontario, Manitoba, and Saskatchewan. Return to table 2 note * referrer

Table 3: Total number of WNV mosquito pools tested by report week and by province/ territory, 2018^{table 3 note ‡}

Province	Report Week																		Total
	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40
Saskatchewan	15	18	17	45	54	79	95	-	-	-	-	-	-	-	-	-	-	-	323
Manitoba	39	89	107	124	122	241	240	-	-	-	-	-	-	-	-	-	-	-	962
Ontario	-	-	-	842	955	1,024	963	-	-	-	-	-	-	-	-	-	-	-	3,784
Québec	69	77	105	105	-	108	-	-	-	-	-	-	-	-	-	-	-	-	573
Total	123	184	229	1,116	1,131	1,532	1,298	-	-	-	-	-	-	-	-	-	-	-	5,642
'-' = Not available. Table 3 notes Table 3 note 1 Detailed West Nile Virus mosquito surveillance data can be accessed through provincial/territorial websites. Return to table 3 note ‡ referrer

Figure 4 notes

Figure 4 note *

Not all provinces conduct dead wild bird surveillance as part of their respective WNV surveillance program. However, WNV positive dead wild birds may be identified through the National Wildlife Disease Surveillance Program, CWHC.

Return to figure 4 note * referrer

Figure 4 - Text description

As of week 29, ending July 21, 2018, there are nine WNV cases in birds, in Canada.

Table showing the reported number of dead birds tested positive for WNV in Canada, by province/territory and by report week, 2018 season.

Province	Jun					Jul				Aug					Sept				Oct				Nov					Total
	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48
Québec	0	0	0	0	0	0	0	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	2
Ontario	0	0	0	0	0	0	0	4	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	4
Manitoba	0	0	3	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	3
Saskatchewan	0	0	0	0	0	0	0	0	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	0
Total	0	0	3	0	0	0	0	6	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	9
'-' = Not available.

Figure 5 notes

Figure 5 note *

Not all provinces conduct dead wild bird surveillance as part of their respective WNV surveillance program. However, WNV positive dead wild birds may be identified through the National Wildlife Disease Surveillance Program, CWHC.

Return to figure 5 note * referrer

Figure 5 - Text description

Table showing percentage of dead wild birds positive for WNV by report week in 2012-2018 and number of dead birds positive in Canada by report week, 2018*

		Jun					Jul				Aug					Sept				Oct				Nov
		22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47
2013	Percentage positive	0	0	0	0	20	0	0	56	20	45	47	38	38	75	69	67	60	67	0	50	100	0	17	0	0	0
2014	Percentage positive	0	0	0	0	0	0	0	0	0	0	15	20	29	31	0	27	75	0	20	0	50	0	0	0	0	0
2015	Percentage positive	0	0	100	0	0	0	100	83	60	73	0	25	67	83	57	50	80	67	0	21	0	0	0	0	50	0
2016	Percentage positive	0	0	0	0	0	0	0	0	0	0	33	50	23	25	80	43	43	20	36	0	80	0	0	0	0	0
2017	Percentage positive	0	0	0	100	25	50	100	33	87	86	53	77	74	87	80	71	57	31	43	33	20	50	50	0	0	0
2018	Percentage positive	0	0	100	0	0	0	0	67	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
2018	Number positive	0	0	3	0	0	0	0	6	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
'-' = Not available.