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Table 2 Summary of p -values for tests of spatial and space-time clustering and clusters, and epidemiological measures of association between occurrence of PRRSV RFLP types and time, space, and ownership in Ontario from 2004–2007

From: Spatial and temporal patterns of porcine reproductive and respiratory syndrome virus (PRRSV) genotypes in Ontario, Canada, 2004–2007

  Wild-type viruses Vaccine-type viruses
RFLP type 1-3-4 1-18-4 1-8-2 1-8-4 2-5-2 1-4-2
  Tests and functions for spatial and space-time clusters and clustering (p-values)
D-function 0.06 0.18 0.35 0.37 0.94 0.11
Space-time K- function 0.63 0.06 0.10 0.86 0.005 0.48
Spatial scan statistica (Bernoulli model) 0.012 0.41 0.22 0.32 0.09 0.60
Spatial scan statistica (Space-time perm. mod.) 0.13 0.08 0.72 0.99 0.04 0.17
  Univariable generalized additive models (p-value and OR b for individual ownerships)
Space (x,y) (p-value) 0.81 0.01 0.71 0.40 0.51 0.94
Time (days) (p-value) 0.008 0.20 0.80 0.62 0.61 0.06
Ownership 3: OR = 4.1 1: OR = 4.9 2: OR = 4.8 2: OR = 12.1 1: OR = 5.9 NSc
Baseline = small owners 4: OR = 7.3 3: OR = 7.4    6: OR = 11.7  
  5: OR = 12.2 5: OR = 6.7     
  Final multivariable generalized additive models (p-value and OR b for individual ownerships)
Space (x,y) (p-value) NId 0.007 NI NI NI NI
Time (days) (p-value) 0.008 NI NI NI NI 0.059
Ownership 3: OR = 6.2 1: OR = 5.7 2: OR = 4.8 2: OR = 12.1 1: OR = 5.9 NI
Baseline = small owners   3: OR = 10.3    6: OR = 11.7  
   5: OR = 15.5     
  1. ap-values obtained for the primary spatial and space-time cluster detected by this method.
  2. bOR = Odds Ratio for individual ownerships using small owners as the baseline. Only comparisons with p < 0.05 are listed in the table. Number before OR corresponds to the ownership code as listed in Table 1.
  3. cNS = No comparisons were significant at p < 0.05.
  4. dNI = Not included in the final model.
  5. Boldface values have p-values < 0.05.