Table 4—
Characteristics of confirmed and probable cases of canine leptospirosis (case; n = 36 to 44) associated with an outbreak between October 2016 and June 2017, in Maricopa County, Ariz, and of control dogs (control; 270 to 281) that also resided in Maricopa County, Ariz, and were enrolled by means of dog owner completion of a survey from July 2017 to August 2017.
| Characteristic | Case dogs | Control dogs | OR (95% CI) |
|---|---|---|---|
| Dogs in the household | n = 36 | n = 281 | |
| Mean ± SD | 2.0 ± 1.8 | 1.7 ± 1.0 | NA |
| Age (y) | n = 44 (%) | n = 276 (%) | |
| < 1 | 5 (11) | 4 (1) | 19.1 (3.6–100.1) |
| 1–3 | 23 (52) | 75 (27) | 4.7 (1.5–14.3) |
| 4–6 | 6 (14) | 64 (23) | 1.43 (0.4–5.3) |
| 7–9 | 6 (14) | 72 (26) | 1.3 (0.3–4.7) |
| ≥ 10 | 4 (9) | 61 (22) | REF |
| Dog type* | n = 42 (%) | n = 270 (%) | |
| Mixed breed | 23 (55) | 142 (53) | REF |
| Herding | 6 (14) | 12 (4) | 3.2 (1.0–9.2) |
| Hound | 3 (7) | 6 (2) | 3.3 (0.8–13.8) |
| Nonsporting | 0 (0) | 20 (8) | 0.148 (0.0008–2.7) |
| Sporting | 7 (17) | 28 (10) | 1.6 (0.6–4.0) |
| Terrier | 1 (2) | 26 (10) | 0.3 (0.1–1.9) |
| Toy | 1 (2) | 28 (10) | 0.3 (0.1–1.8) |
| Working | 1 (2) | 8 (3) | 1.1 (0.2–7.0) |
| Weight (kg) | n = 44 (%) | n = 281 (%) | |
| < 15 | 13 (30) | 147 (52) | REF |
| ≥ 15 | 31 (70) | 134 (48) | 2.6 (1.3–5.2) |
| Sex | n = 44 (%) | n = 280 (%) | |
| Female | 16 (36) | 157 (56) | REF |
| Male | 28 (64) | 123 (44) | 2.2 (1.1—4.2) |
| Neuter status | n = 44 (%) | n = 280 (%) | |
| Sexually intact | 6 (14) | 12 (4) | REF |
| Neutered | 38 (86) | 268 (96) | 0.3 (0.1–0.8) |
| Dog role† | n = 44 (%) | n = 281(%) | |
| Pet | 43 (98) | 279 (99) | NA |
| Hunting | 1 (2) | 1 (< 1) | NA |
| Guard | 1 (2) | 8 (3) | NA |
| Service or emotional support | 1 (2) | 2 (< 1) | NA |
| Show | 0 (0) | 1 (< 1) | NA |
*
Purebred dogs were assigned to American Kennel Club–recognized breed groups.
†
Categories not mutually exclusive. NA = Not applicable. REF = Reference group for calculation of OR.