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Volume 13, Number 9—September 2007

Spectrum of Infection and Risk Factors for Human Monkeypox, United States, 2003

Mary G. Reynolds*Comments to Author , 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*
Author affiliations: *Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †Illinois Department of Public Health, Chicago, Illinois, USA; ‡Rush University, Chicago, Illinois, USA; §Wisconsin Department of Health and Family Services, Madison, Wisconsin, USA; ¶Kansas Department of Health and Environment, Topeka, Kansas, USA; #Indiana State Department of Health, Indianapolis, Indiana, USA;

Main Article

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)
Female 17 (56.7) 16 (57.1) 1.0 (0.3–2.8) 0.9 (0.3–2.7)
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)
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.

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