Volume 13, Number 9—September 2007
Research
Spectrum of Infection and Risk Factors for Human Monkeypox, United States, 2003
, Whitni B. Davidson*, Aaron T. Curns*, Craig S. Conover†, Gregory Huhn*‡, Jeffrey P. Davis§, Mark Wegner§, Donita R. Croft§, Alexandra Newman*§, Nkolika N. Obiesie¶, Gail R. Hansen¶, Patrick L. Hays¶, Pamela Pontones#, Brad Beard#, Robert Teclaw#, James F. Howell#, Zachary Braden*, Robert C. Holman*, Kevin L. Karem*, and Inger K. Damon*Table 3
Smallpox vaccination status, demographic characteristics, and potential exposures to infected prairie dogs among case-patients and controls, monkeypox virus outbreak, United States, 2003*
| Characteristic | Case-patients, no. (%) | Controls, no. (%) | OR (95% CI) | aOR (95% CI) |
|---|---|---|---|---|
| Smallpox vaccination | ||||
| Yes | 6 (20.0) | 15 (53.6) | 0.2 (0.1–0.7) | |
| No | 24 (80.0) | 13 (46.7) | ||
| Age, y† | ||||
| <18 | 10 (33.3) | 7 (25.0) | 1.5 (0.5–4.7) | 0.6 (0.2–2.4) |
| >18 | 20 (66.7) | 21 (75.0) | ||
| Sex | ||||
| Female | 17 (56.7) | 16 (57.1) | 1.0 (0.3–2.8) | 0.9 (0.3–2.7) |
| Male |
13 (43.3) |
12 (42.9) |
||
| Type of exposure to prairie dog(s) | ||||
| Animal as pet | ||||
| Yes | 17 (56.7) | 9 (32.1) | 2.8 (0.9–8.1) | 2.4 (0.8–7.4) |
| No | 13 (43.3) | 19 (67.9) | ||
| Daily exposure while animal was ill | ||||
| Yes | 23 (76.7) | 13 (46.4) | 3.8 (1.2–11.7) | 4.0 (1.2–13.4) |
| No | 7 (23.3) | 15 (53.6) | ||
| Touched rash or eye crusts | ||||
| Yes | 18 (60.0) | 11 (39.3) | 2.3 (0.8–6.6) | 2.2 (0.7–6.7) |
| No | 12 (40.0) | 17 (60.7) | ||
| Scratched‡ | ||||
| Yes | 9 (30.0) | 2 (7.1) | 5.6 (1.1–28.6) | 3.9 (0.7–21.1) |
| No | 21 (70.0) | 26 (92.9) | ||
| Cleaned cage/touched bedding | ||||
| Yes | 14 (46.7) | 4 (14.3) | 5.3 (1.5–18.9) | 5.3 (1.4–20.7) |
| No | 16 (53.3) | 24 (85.7) | ||
| Proximity, no touching§ | ||||
| Yes | 12 (40.0) | 7 (25.0) | 2.0 (0.6–6.2) | 2.0 (0.6–6.5) |
| No | 18 (60.0) | 21 (75.0) | ||
| Direct exposure¶ | ||||
| Yes | 23 (76.7) | 13 (46.4) | 3.8 (1.2–11.7) | 4.0 (1.2–13.4) |
| No | 7 (23.3) | 15 (53.6) | ||
*OR, odds ratio; CI, confidence interval; aOR, adjusted OR. The aORs and 95% CIs were adjusted for history of (>1) smallpox vaccination at any time during case-patient’s life.
†Routine immunization was stopped in the United States in 1972 (18), persons <33 years of age at the time of the outbreak were unlikely to have received prior smallpox vaccination.
‡Scratched with a break in the skin.
§Came within 6 feet of the prairie dog but never touched it.
¶Direct exposure to an infected animal included having touched the animal or having received a bite or scratch from it sufficient to break the skin.
