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Volume 16, Number 8—August 2010


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 2

MLEs and MIRs of 2-week infection rate in Culex tarsalis mosquitoes, South Okanagan Valley, British Columbia, 2009*

Week Total no. individuals No. pools No. positive pools MLE (95% CI) MIR
Jun 28–Jul 11 1,542 52 0 0.00 0.00
Jul 12–Jul 25 670 30 0 0.00 0.00
Jul 26–Aug 8 3,376 98 4 1.21 (0.39–2.92) 1.85
Aug 9–Aug 22 959 67 4 4.49 (1.45–10.95) 4.17
Aug 23–Sep 5 424 37 2 4.97 (0.89–16.63) 4.71
Sep 6–Sep 19 4 1 0 0.00 0.00

*MLE, maximum-likelihood estimate; MIR, minimum infectious rate estimate; CI, confidence interval. Estimates are calculated by using the software PooledInfRate from Centers for Disease Control and Prevention (24) and represent number of positive mosquitoes per 1,000 tested. Values within parentheses represent 95% confidence intervals.

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.