Table 3. Comparison of sociodemographic and clinical characteristic of participants with symptomatic versus asymptomatic chikungunya virus infection Salvador, Brazil, November 2016 to February 2017*.
| Characteristic | Disease status of infected participants, no. %† |
p value | |
|---|---|---|---|
| Symptomatic, n = 32 | Asymptomatic, n = 177 | ||
| Sociodemographic | |||
| Sex | |||
| M | 12 (37.5) | 81 (45.8) | 0.39 |
| F | 20 (62.5) | 96 (54.2) | |
| Age, y | |||
| 5–14 | 2 (6.3) | 40 (22.6) | 0.07 |
| 15–39 | 22 (68.8) | 82 (46.3) | |
| ≥40 | 8 (24.9) | 55 (31.1) | |
| Education‡ | |||
| Illiterate | 1 (3.1) | 13 (7.4) | 0.42 |
| Literate | 31 (96.9) | 163 (92.6) | |
| Skin color | |||
| White | 0 | 10 (5.7) | NA |
| Nonwhite | 32 (100) | 167 (94.3) | |
| Household per capita income, US$/day‡ | |||
| ≤5.50 | 27 (84.4) | 144 (81.8) | 0.73 |
| >5.50 |
5 (15.6) |
32 (18.2) |
|
| Clinical: reported symptoms | |||
| Fever and arthralgia | |||
| None | 0 | 111 (62.7) | <0.01 |
| Only fever | 0 | 39 (22.0) | |
| Only arthralgia | 0 | 20 (11.3) | |
| Both, not simultaneous | 0 | 7 (4.0) | |
| Both, simultaneous | 32 (100) | 0 | |
| Myalgia | |||
| Yes | 18 (56.3) | 24 (13.6) | <0.01 |
| No | 14 (43.7) | 153 (86.4) | |
| Rash | |||
| Yes | 22 (68.7) | 28 (15.9) | <0.01 |
| No | 10 (31.3) | 148 (84.1) | |
| Pruritus | |||
| Yes | 21 (65.6) | 25 (14.1) | <0.01 |
| No |
11 (34.4) |
152 (85.9) |
|
| Presumptive clinical diagnosis | |||
| Chikungunya | |||
| Yes | 20 (62.5) | 12 (6.8) | <0.01 |
| No | 12 (37.5) | 165 (93.2) | |
| Dengue | |||
| Yes | 4 (12.5) | 17 (9.6) | 0.62 |
| No | 28 (87.5) | 160 (90.4) | |
| Zika | |||
| Yes | 18 (56.3) | 20 (11.3) | <0.01 |
| No | 14 (43.7) | 157 (88.7%) | |
*NA, not available †CHIKV disease status was defined as symptomatic on the basis of self-reported fever accompanied by arthralgia after January 2015. ‡Data not available for 1 participant with an asymptomatic CHIKV infection.