Table 1.
Results of Lyme disease surveillance in humans and passive I. scapularis tick surveillance from 2009 through 2016 in Ontario and Manitoba.
Fig 1.
Negative binomial generalized estimating equation models of the relationship between the numbers of passive single I. scapularis tick submissions and reported Lyme disease cases per CSD, over 2 years.
Numbers of tick submissions for all I. scapularis (adults and nymphs) in Ontario and Manitoba are illustrated respectively in A and B, whereas the numbers of nymphal tick submissions for Ontario are shown in C. The numbers of reported Lyme disease cases per CSD are illustrated by the circles and the model prediction by the solid line (dashed lines show the 95% confidence limits for the fitted model). Note that there are differences in the axis scales between the Figs.
Table 2.
Negative binomial generalized estimating equation models testing for the influence of the number of I. scapularis tick submissions on the occurrence of human Lyme disease cases; adult and nymphal I. scapularis submissions (Model 1) and nymphal I. scapularis submissions (Model 2) detected by the passive tick surveillance program in Ontario and Manitoba.
Fig 2.
Sensitivity and specificity curves of the range of cut-off point number of I. scapularis (adults and nymphs) submissions in Ontario and Manitoba (A and B) and nymphal I. scapularis submissions in Ontario (C). The straight dashed line corresponds to the intersection between Se and Sp curves, the optimal cut-off point which maximize the Se and Sp over a range of cut-off points of the number of tick submissions. A− C illustrate the optimal cut-off points of cumulated 12, 5 and 2 tick submissions over five-year period to discriminate CSDs with ≥ 3 human Lyme disease cases.
Table 3.
The performances of the optimal risk indicators and their validation under the current epidemiologic Lyme disease situation.
Fig 3.
Geographic distribution of passive I. scapularis tick submissions (adults and nymphs) and total number of reported human Lyme disease cases in CSDs in Ontario from 2011 to 2015.
Dotted CSDs are areas with emerging risk (1–2 human Lyme disease cases). Hatched CSDs are endemic areas where ≥ 3 Lyme disease cases were acquired. Light blue CSDs are areas where the number of adult and nymphal is < 12, the optimal cut-off point as indicator of the human Lyme disease risk. Dark blue CSDs are areas where the number of I. scapularis submissions is ≥ 12.
Fig 4.
Geographic distribution of passive I. scapularis tick submissions (adults and nymphs) and total number of human Lyme disease cases in CSDs in Manitoba from 2011 to 2015.
Dotted CSD are areas with emerging risk (1–2 human Lyme disease cases). Hatched CSD are endemic areas where ≥ 3 Lyme disease cases were acquired. Light blue CSDs are areas where the number of adults and nymphs is < 5, the optimal cut-off point as a predictor of the human Lyme disease risk. Dark blue CSDs are areas where the number of ticks is ≥ 5.