Number of RMSF cases (both confirmed and probable) by month of onset, 1980 to 2019, stratified by 20-year reporting blocks.

Number of RMSF cases (both confirmed and probable) by month of onset, 1980 to 2019, stratified by 20-year reporting blocks.</p

Confirmed and probable cases of RMSF in California and percent of reported cases confirmed in two 20-year time blocks, 1980 to 1999 and 2000 to 2019.

Confirmed and probable cases of RMSF in California and percent of reported cases confirmed in two 20-year time blocks, 1980 to 1999 and 2000 to 2019.</p

Number and percentage of California RMSF cases where regions of exposure prior to onset could be determined in 20-year reporting blocks, 1980–2019.

Exposure regions are “Northern CA” (California counties north of San Luis Obispo, Kern and San Bernardino Counties; see Fig 4), “Southern CA” (counties not in Northern CA), “US” (any state outside California in the United States) and “Unknown” (travel not specified).</p

Flow of case evaluation for inclusion in this analysis.

Case reports retrieved from 1980 to 2019 include all those reported as Rocky Mountain spotted fever (RMSF). Conservative case inclusion criteria were applied as described in methods to focus on those cases most likely to be RMSF. Included in the analysis were 31 confirmed cases and 47 probable cases.</p

Demographics, hospitalization, and fatality of reported RMSF cases in California in two 20-year reporting blocks, 1980 to 1999 and 2000 to 2019.

Asterisks indicate where there are statistically differences in proportions with a Z test, p < 0.05 considered significant.</p

The Excel tables in the supplementary information contain aggregated data used to make Figs 1–5.

Each figure is under a separate tab. (XLSX)</p