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Table 2 Validation of the nymphal tick immigration index.

From: Risk maps for range expansion of the Lyme disease vector, Ixodes scapularis, in Canada now and with climate change

Variable Factor Coefficient (SE) Wald z
Index of tick immigration   0.043 (0.004) 10.86***
Province Newfoundland & Labrador Reference factor
  Saskatchewan -2.524 (0.254) -4.12***
  Manitoba 1.692 (0.289) 5.85***
  Ontario -1.27 (0.299) -4.24***
  Quebec -0.405 (0.304) 1.33
  New Brunswick 0.482 (0.303) 1.59
  Prince Edward Island 3.131 (0.315) 9.93***
  Nova Scotia 0.583 (0.349) 1.67
Constant   -9.831 (0.254) -38.65
  1. *** = P < 0.001
  2. The association of the nymphal tick immigration index with the number of I. scapularis submitted in each Canadian census sub-division in passive surveillance in Canada from 1990 to 2003 was investigated using a multivariable negative binomial regression model. In this model nymphal tick immigration index and Province were explanatory variables, and the natural logarithm of human population was included as an offset.