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Volume 16, Number 8—August 2010

Research

West Nile Virus Range Expansion into British Columbia

David RothComments to Author , Bonnie Henry, Sunny Mak, Mieke Fraser, Marsha Taylor, Min Li, Ken Cooper, Allen Furnell, Quantine Wong, Muhammad Morshed, and Members of the British Columbia West Nile Virus Surveillance Team1
Author affiliations: British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada (D. Roth, B. Henry, S. Mak, M. Fraser, M. Taylor, M. Li, K. Cooper, A. Furnell, Q. Wong, M. Morshed; University of British Columbia, Vancouver (D. Roth, B. Henry, M. Morshed)

Main Article

Table 1

Summary of British Columbia WNV surveillance activities during the WNV seasons of 2004–2009*

Surveillance type 2004 2005 2006 2007 2008 2009
Mosquito
No. permanent trap locations 145 189 148 155 98 91
No. mosquitoes collected
52,657
198,228
394,047
242,215
202,460
181,942
Mosquito pools† 2,980 6,631 2,329 2,568 1,873 1,469
Provincial
No. Culex pipiens 4.6 5.1 8.6 14.3 10.5 21.1
No. Cx. tarsalis 0.8 1.9 4.8 3.5 1.4 11.8
Interior‡
No. Cx. pipiens 12.6 8.9 9.5 8.2 4.7 7.6 (9.3)
No. Cx. tarsalis 11.0 12.0 22.5 10.1 2.9 33.1 (14.3)
Fraser
No. Cx. pipiens 10.5 13.0 22.3 32.5 33.7 36.1
No. Cx. tarsalis
6.9
4.9
7.7
7.1
7.0
15.1
Bird
No. corvids sighted 1,292 740 605 562 458 355
No. corvids submitted 1,437 1,058 803 740 205 144
No. corvids positive
0
0
0
0
0
0
Human
No. tested 481 755 239 805 530 340
No. positive§ 0 0 0 19 (0) 0 3 (2)

*WNV, West Nile Virus.
†Values represent average trap catch. Provincial, average trap catch for all traps in British Columbia; Interior, average trap catch from the Interior Health Authority, which includes the southern Okanagan Valley (Figure 2); Fraser, average trap catch from the Fraser Health Authority (Figure 2).
‡Values represent average trap catch from all traps run in the southern Okanagan Valley in 2009, including 16 traps run in the area as part of a research project. Values within parentheses represent average trap catch without the research traps.
§No. human cases detected in British Columbia (no. cases acquired within British Columbia).

Main Article

1Members of the British Columbia WNV Surveillance Team: Lucy Beck, Victoria Bowes, Elizabeth Brodkin, Steve Chong, Ken Christian, Dalton Cross, Murray Fyfe, Roland Guasparini, Paul Hasselback, Randy Heilbron, Mira Leslie, James Lu, Craig Nowakowski, Robert Parker, Tim Shum, Kevin Touchet, and Eric Young.

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