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Table 4 Summary of rickettsiae-seropositive and seronegative cases and patients, Ontario, Canada (2013–2018)

From: Assessing human exposure to spotted fever and typhus group rickettsiae in Ontario, Canada (2013–2018): a retrospective, cross-sectional study

Variable Seropositive cases Seronegative patients
Total, n 626 2129
Female, n (%) 297 (47.4) 1253 (58.8)
Age, mean ± SE (range)a 42.9 ± 0.76 (<  1–89) 43.0 ± 0.40 (<  1–90)
Sera samples/patient, mean ± SE (range)b 1.3 ± 0.026 (1–7) 1.1 ± 0.0067 (1–4)
Year of onset, n
 2013 41 276
 2014 49 279
 2015 69 275
 2016 76 413
 2017 164 465
 2018 227 421
Signs and symptoms, n (%)c
None reported 387 (61.8) 1361 (63.9)
 Headache 134 (54.0) 263 (33.1)
 Fever 75 (30.2) 253 (31.8)
 Fatigue 65 (26.2) 225 (28.3)
 Gastrointestinal complaints 27 (10.9) 86 (10.8)
 Respiratory complaints 21 (8.5) 59 (7.4)
 Arthralgia/arthritis 19 (7.7) 65 (8.2)
 Rash (maculopapular) 15 (6.0) 79 (9.9)
 Rash (not described) 13 (5.2) 51 (6.4)
 Tick bite 13 (5.2) 46 (5.8)
 Encephalitis/meningitis 12 (4.8) 23 (2.9)
 Rash (vesicular) 10 (4.0) 27 (3.4)
 Malaise/unwell 9 (3.6) 5 (0.6)
 Myalgia/body aches 7 (2.8) 10 (1.3)
 Chills 2 (0.8) 8 (1.0)
 Elevated liver enzymes 2 (0.8) 7 (0.9)
 Jaundice 2 (0.8) 5 (0.6)
 Anemia 1 (0.4) 2 (0.3)
 Anxiety 1 (0.4) 2 (0.3)
 Dizziness 1 (0.4) 5 (0.6)
 Confusion 0 (0.0) 2 (0.3)
 Hepatitis 0 (0.0) 2 (0.3)
 Edema 0 (0.0) 1 (0.1)
  1. Abbreviations: n/a not applicable
  2. a Sex of some patients was not available
  3. bt = 7.3, df = 706, p < 0.0001
  4. c Cases and patients reporting at least one sign or symptom: seropositive, n = 239; seronegative, n = 768. Some cases and patients have > 1 sign or symptom. Denominator is based on number of cases or patients with at least one symptom reported on the requisition