Table 4.
Summary of rickettsiae-seropositive and seronegative cases and patients, Ontario, Canada (2013–2018)
| 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) |
Abbreviations: n/a not applicable
a Sex of some patients was not available
bt = 7.3, df = 706, p < 0.0001
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