Table 3.
Mixed-effect logistic regression of residents self-reporting tick infestation of the property and potential risk factors during a survey for brown dog tick infestation and Rocky Mountain spotted fever in Tijuana, México
| Predictor | No. (%) with Ticks/Total | OR | 95% CI | P-Value |
|---|---|---|---|---|
| Univariable Models | ||||
| Case/control | ||||
| Case | 8/31 (25.8) | 0.56 | 0.19–1.64 | 0.29 |
| Control | 44/118 (37.3) | Reference | – | – |
| Marginalization | ||||
| Medium | 24/57 (42.1) | Reference | – | – |
| High | 17/61 (27.9) | 0.5 | 0.20–1.27 | 0.14 |
| Very high | 11/31 (35.5) | 0.71 | 0.23–2.16 | 0.54 |
| Debris | ||||
| None | 13/38 (34.2) | Reference | – | – |
| A little | 25/76 (32.9) | 0.77 | 0.29–2.01 | 0.59 |
| A lot | 10/25 (40.0) | 1.5 | 0.44–5.16 | 0.52 |
| On a hill | ||||
| No | 27/77 (35.1) | Reference | – | – |
| Yes | 25/71 (35.2) | 1.18 | 0.50–2.75 | 0.71 |
| On a dirt road | ||||
| No | 26/60 (43.3) | Reference | – | – |
| Yes | 26/89 (29.2) | 0.52 | 0.24–1.15 | 0.11 |
| Near a canal | ||||
| No | 44/128 (34.4) | Reference | – | – |
| Yes | 8/19 (42.1) | 1.26 | 0.41–3.89 | 0.69 |
| Cement | 1 | 0.99–1.01 | 0.41 | |
| No. of people living in home | 0.96 | 0.84–1.10 | 0.59 | |
| No. of dogs at house | 1.06 | 0.88–1.27 | 0.57 | |
| Total No. of dogs seen | 1.07 | 0.93–1.24 | 0.31 | |
| Ownership and dog presence | ||||
| Owned | 45/114 (39.8) | 6.87 | 1.29–36.64 | 0.02 |
| Seen, not owned | 5/19 (26.3) | 3.28 | 0.46–23.26 | 0.23 |
| No dogs observed | 2/17 (11.8) | Reference | – | |
| Dog allowed inside* | ||||
| Inside | 21/51 (41.2) | 1.19 | 0.47–3.02 | 0.71 |
| Not | 24/62 (38.7) | Reference | – | – |
| Frequency of treating house with acaricide | ||||
| Never or rarely | 17/51 (33.3) | Reference | – | – |
| 1 or 2 times/year | 21/57 (36.8) | 1.11 | 0.47–2.61 | 0.82 |
| Multiple times/year | 12/36 (33.3) | 1 | 0.38–2.67 | 1.0 |
| Frequency of treating dogs with acaricide* | ||||
| Never or rarely | 7/26 (26.9) | Reference | – | – |
| 1 or 2 times/year | 20/41 (48.8) | 3.35 | 0.93–12.06 | 0.06 |
| Multiple times/year | 15/38 (39.5) | 2.14 | 0.59–7.71 | 0.25 |
| Dogs allowed to roam* | ||||
| No | 21/53 (39.6) | Reference | – | – |
| Yes | 21/46 (45.7) | 1.06 | 0.40–2.79 | 0.90 |
| Tick burden on dogs | ||||
| None | 18/44 (40.9) | Reference | – | – |
| 10–20 | 13/39 (33.3) | 0.76 | 0.26–2.21 | 0.61 |
| >10 | 13/23 (56.5) | 2.37 | 0.67–8.37 | 0.18 |
| Has heard of RMSF | ||||
| Yes | 40/101 (39.6) | 2.03 | 0.86–4.75 | 0.10 |
| No | 12/48 (25.0) | Reference | – | – |
| Multivariable Model | ||||
|---|---|---|---|---|
| (Intercept) | – | 0.12 | 0.04–0.36 | <0.001 |
| Owns a dog | 3.87 | 1.40–10.68 | 0.009 | |
| House not on a dirt road | 2.44 | 1.03–5.81 | 0.04 | |
OR = odds ratio; RMSF = Rocky Mountain spotted fever.
*
Analysis restricted to houses with dogs.