Volume 29, Number 3—March 2023
Research
Increase in Colorado Tick Fever Virus Disease Cases and Effect of COVID-19 Pandemic on Behaviors and Testing Practices, Montana, 2020
Raymond A. Soto, Erika Baldry, Grace M. Vahey, Jennifer Lehman, Margaret Silver, Amanda Panella, Aaron C. Brault, Holly R. Hughes, Kelly A. Fitzpatrick, Jason Velez, Brad J. Biggerstaff, Brent Wolff, Jean Randolph, Laird J. Ruth, J. Erin Staples, and Carolyn V. Gould
Table 3
Outdoor and tick exposures during the 2 weeks before illness onset for participants in a Colorado tick fever case–control study, Montana, USA, 2020*
| Risk factor | Case-patients, n = 14 | Controls, n = 22 | OR or SD (95% CI) |
|---|---|---|---|
| Employment status | |||
| Employed | 7 (50) | 12 (55) | 0.8 (0.2–3.1) |
| Retired | 2 (14) | 4 (18) | 0.7 (0.1–4.2) |
| Student or dependent child |
5 (36) |
5 (23) |
1.9 (0.4–7.9) |
| Occupational outdoor activities |
5/7 (71) |
4/12 (33) |
5.0 (0.7–33.5) |
| More outdoor recreation because of COVID-19 pandemic |
6 (43) |
10 (45) |
0.9 (0.2–3.4) |
| Recreational outdoor activities | |||
| >4 h outside per weekday | 6 (43) | 5 (23) | 2.5 (0.6–10.5) |
| >4 h outside per weekend day |
12 (86) |
11 (50) |
6.0 (1.2–29.2) |
| Average total time outside, h (SD) |
83.3 (77.2) |
51.3 [47.5) |
31.9 (–16.1 to 80.0) |
| Specific recreational outdoor activities | |||
| Yard work or gardening | 8 (58) | 15 (68) | 0.6 (0.2 to 2.4) |
| Average no. times (SD) | 2.9 (1.7) | 7 [4.7) | –4.0 (–6.8 to –1.2) |
| Hunting or fishing | 5 (36) | 7 (32) | 1.2 (0.3 to 4.7) |
| Average no. times (SD) | 2.8 (1.6) | 3.1 [1.0) | –0.3 (–2.4 to 1.7) |
| Hiking/walking/running on unpaved trails | 12 (86) | 15 (68) | 2.8 (0.5 to 13.9) |
| Average no. times (SD) | 5.6 (3.5) | 8.9 [6.0) | –3.3 (–7.2 to 0.7) |
| Camping | 6 (43) | 6 (27) | 2.0 (0.5 to 8.0) |
| Average no. times (SD) | 4.2 (1.7) | 2.8 [1.2) | 1.3 (–0.6 to 3.3) |
| Off-road mountain biking | 2 (14) | 5 (23) | 0.6 (0.1 to 3.1) |
| Average no. (SD) |
5 (0) |
3.3 [2.2) |
1.7 (–1.0 to 4.4) |
| Personal tick prevention measures | |||
| Used repellent or repellent-treated clothing | 3 (21) | 10 (45) | 0.3 (0.1–1.4) |
| Checked self for ticks | 14 (100) | 10 (45) | 34.5 (3.0–365.3) |
| Wore long pants | 11 (78) | 15 (68) | 1.7 (0.4–7.5) |
| Wore long sleeves |
12 (86) |
14 (64) |
3.4 (0.7–16.9) |
| Found a tick on self | 14 (100) | 9 (41) | 41.2 (3.5–436.6) |
| Found tick attached to self |
13 (93) |
8 (36) |
22.7 (3.0–156.0) |
| Location where tick acquired | |||
| National Forest | 8/12 (67) | 4/4 (100) | 0.2 (0.0–3.0) |
| State Park | 2/12 (17) | 0/4 (0) | 2.1 (0.1–27.0) |
| Private land | 2/12 (17) | 0/4 (0) | 2.1 (0.1–27.0) |
*Values are no (%) except as indicated. Bold indicates statistical significance (α = 0.05). OR, odds ratio.
Page created: December 27, 2022
Page updated: February 19, 2023
Page reviewed: February 19, 2023
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