Table 1.
Comparison of Characteristics and Potential Risk Factors of Exposed Infected versus Noninfected OIF Veterans (n = 200)
| Infected n (%) |
Not Infected n (%) |
P | |
|---|---|---|---|
| 39 (100) | 161 (100) | ||
| Mean current age (range) | 40.5 years (28–58) |
41.2 years (24–61) |
NSd |
| Sex | NSe | ||
| Male | 35 (89.7) | 133 (82.6) | |
| Female | 4 (10.3) | 28 (17.4) | |
| Race | NSe | ||
| White | 32 (82.1) | 126 (78.3) | |
| Black/African American | 5 (12.8) | 20 (12.4) | |
| Asian | 0 | 6 (3.7) | |
| Pacific Islander | 1 (2.6) | 2 (1.2) | |
| Other | 1 (2.6) | 7 (4.3) | |
| Service | NSe | ||
| Army | 34 (87.2) | 143 (88.8) | |
| Marine Corps | 2 (5.1) | 9 (5.6) | |
| Navy | 3 (7.7) | 6 (3.7) | |
| Air Force | 0 | 3 (1.9) | |
| Rank | |||
| Officer | 15 (38.5) | 56 (34.8) | NSe |
| Enlisted | 24 (61.5) | 105 (65.2) | |
| Military occupation in Iraq | NSe | ||
| Combat arms | 4 (10.3) | 37 (23.0) | |
| Aviation | 3 (7.7) | 8 (5.0) | |
| Special operationsa | 0 | 11 (6.8) | |
| Combat support | 7 (18.0) | 31 (19.3) | |
| Healthcare | 16 (41.0) | 46 (38.6) | |
| Administration | 4 (10.3) | 16 (9.9) | |
| Supply | 4 (10.3) | 4 (2.5) | |
| Mechanic | 0 | 4 (2.5) | |
| Transportation | 1 (2.6) | 4 (2.5) | |
| Median days deployedb in Iraq (range) | 361 (93–517) |
321 (30–790) |
NSf |
| Total deployments to Iraq or Afghanistan since 2001 | NSe (for trend) |
||
| 1 | 12 (30.8) | 56 (34.8) | |
| 2–4 | 22 (56.4) | 95 (59.0) | |
| 5 or more | 5 (12.8) | 10 (6.2) | |
| Summer evening outdoor activitiesc | NSe | ||
| 2–4 days/week | 7 (18.5) | 19 (11.8) | |
| Five or more days/week | 31 (81.6) | 142 (88.2) | |
| Typical summer sleepwear | NSe | ||
| Full uniform ± boots | 7 (18) | 16 (9.9) | |
| Shorts and t-shirt (physical fitness uniform) | 23 (59.0) | 87 (54.0) | |
| “Skivvies” only | 7 (18) | 46 (28.6) | |
| Other | 2 (5.1) | 11 (6.8) | |
| Summer sleep conditions | |||
| Total no. of nights (mean) | 7228 (185) | 27681 (188) | |
| Percentage of all nights on ground (vs. bed/cot) | 19.5% | 13.5% | NSe |
| Exposure to dogs | NSe | ||
| Had a local pet | 4 (10.3) | 14 (8.7) | |
| Others in unit had a pet | 14 (35.9) | 62 (38.5) | |
| Worked with military working dogs | 3 (7.7) | 12 (7.5) | |
| Little or no direct contact | 23 (59) | 89 (55.3) | |
| Use of DEET insect repellent | NSe | ||
| None | 16 (41) | 64 (39.8) | |
| Brought own brand | 4 (10.3) | 15 (9.3) | |
| Used military issued repellent | 10 (25.6) | 54 (33.5) | |
| Used both | 9 (23.1) | 28 (17.4) | |
| Frequency of repellent use | NSe | ||
| Never | 17 (43.6) | 60 (37.3) | |
| ≤ 1/week | 13 (33.3) | 69 (42.9) | |
| >1/week | 4 (10.3) | 21 (13.0) | |
| Daily | 5 (12.8) | 11 (6.8) | |
| Permethrin–treated uniforms | NSe | ||
| None | 15 (38.5) | 64 (39.8) | |
| Unknown | 2 (5.1) | 20 (12.4) | |
| Some uniforms treated | 12 (30.8) | 34 (21.1) | |
| All uniforms treated | 10 (25.6) | 43 (26.7) | |
| †Sand fly saliva antibodies detected | 30 (76.9) | 98 (60.9) | P = .06e |
| Constitutional symptoms (in previous 3 months) | NSe | ||
| Fever | 5 (12.8) | 15 (9.3) | |
| Night sweats | 9 (23.1) | 36 (22.4) | |
| Weight loss | 0 | 5 (3.1) | |
| Fatigue | 12 (30.8) | 44 (27.3) | |
| Skin rash | 10 (25.6) | 37 (23.0) | |
| Multiple symptoms reported | NSe | ||
| >3 | 4 (10.3) | 1 (.06) | |
| 3 | 1 (2.6) | 2 (1.2) | |
| 2 | 6 (15.4) | 2 (1.2) | |
| Postdeployment hospitalization | 11 (28.2) | 43 (26.7) | NSe |
Infection defined as positive by polymerase chain reaction, interferon-y release assay, or serology. Individual comparison level of significance P = .05. No correction for multiple positive comparisons was performed.
Abbreviations: DEET, N,N-diethyl-meta-toluamide; NS, nonsignificant; OIF, Operation Iraqi Freedom.
aSalivary gland homogenate ELISA antibody.
bDuring first Iraq deployment.
cNo response from one infected participant.
dMeans compared with Student’s t-test.
eProportions compared with χ2 or Fisher’s exact test.
fRank sums compared with Mann-Whitney test.