The demarcation of these seasons was useful in the determination of the perceived dates of onset and cessation of rainfall by respondents.
The main indicators of change (of rainfall pattern) were increase in frequency of extreme events (specifically prolonged drought) (43%), change in rainfall amount (43%), change in dates of onset (5%), and reduced growing season (5%) (Fig. 2).
For ct, we use the published dates of onset among confirmed cases, while fs is assumed known.
In the USA, there were 399 confirmed cases by May 1, with 394 known dates of onset (Figure 2A).
The duration of the cluster was defined as the time between the dates of onset of the index case and of the last case in the cluster.
In Canada, there were 2978 confirmed cases, with 2004 known dates of onset by June 10, among which 4 cases died by June 10 (Figure 2B).
Phenotypic data were collected by patient questionnaire, interview and casenote review and were composed of demographics, dates of onset and diagnosis, disease location/extent, disease behaviour, surgical operations, smoking history and family history.
Although this has little impact on the estimate for the USA, the cCFR in Canada is likely to be underestimated by our estimator, because the majority of the 974 cases whose dates of onset have yet to be clarified, may have experienced their symptom onset close to the latest time point of observation.
Additionally, dates of onset were not reliably recorded.
Dates of onset ranged from February 25 to March 16.
The 26 primary cases had dates of onset from November 3 through November 24.
