Table. Covariates associated with seropositivity for typhus group rickettsiae, Mbeya region, southwestern Tanzania, 2007* .
| Covariate/stratum | No. specimens (% positive) | Univariable†‡ |
Multivariable†§ |
|||
|---|---|---|---|---|---|---|
| PR (95% CI) |
p value |
PR (95% CI) |
p value |
|||
| Age, y | ||||||
| 5–<13.6 | 245 (5.3) | 1 | – | 1 (–) | – | |
| 13.6–<27.7 | 245 (6.5) | 1.23 (0.60–2.51) | 0.568 | 1.28 (0.63–2.58) | 0.495 | |
| 27.8–<42.1 | 243 (12.3) | 2.33 (1.23–4.39) | 0.009 | 2.40 (1.28–4.49) | 0.006 | |
| 42.1–55.2 | 248 (14.9) | 2.81 (1.53–5.18) | 0.001 | 2.73 (1.49–4.99) | 0.001 | |
| >55.2 |
246 (7.3) |
1.38 (0.69–2.76) |
0.365 |
|
1.41 (0.71–2.80) |
0.331 |
| Distance to nearest highway, km | 1,227 (9.3) | 0.96 (0.94–0.99) | 0.012 | 0.97 (0–0.99) | 0.011 | |
| Enhanced vegetation index, per 0.1 units | 1,227 (9.3) | 0.58 (0.44–0.76) | <0.001 | 0.60 (0.46–0.79) | <0.001 | |
| Persons/km2, per 1,000 persons |
1,227 (9.3) |
1.08 (1.04–1.12) |
<0.001 |
|
|
|
| Sex | ||||||
| F | 672 (8.6) | 1 | – | |||
| M | 544 (9.9) | 1.15 (0.81–1.63) | 0.430 | |||
| Unknown |
11 (18.2) |
2.11 (0.59–7.58) |
0.254 |
|
|
|
| SES rank, per unit¶ |
1,227 (9.3) |
1.08 (1.02–1.15) |
0.008 |
|
|
|
| Cattle/km2, per 100 cattle | 1,227 (9.3) | 1.28 (1.05–1.56) | 0.017 | |||
| No. cows owned | 1,227 (9.3) | 0.96 (0.84–1.09) | 0.526 | |||
| No. goats owned |
1,227 (9.3) |
0.94 (0.83–1.07) |
0.367 |
|
|
|
| Dogs owned | ||||||
| No | 820 (8.8) | 1 | – | |||
| Yes | 191 (8.4) | 0.95 (0.54–1.67) | 0.869 | |||
| No information |
216 (12.0) |
1.37 (0.89–2.11) |
0.150 |
|
|
|
| Minimum ambient temperature, °C | 1,227 (9.3) | 0.92 (0.87–0.97) | 0.004 | |||
| Average day land surface temperature, °C | 1,227 (9.3) | 1.37 (0.71–2.63) | 0.351 | |||
| Average night land surface temperature, °C |
1,227 (9.3) |
0.61 (0.38–0.99) |
0.044 |
|
|
|
| Elevation, per 100 m | 1,227 (9.3) | 1.04 (1.00–1.08) | 0.025 | |||
| Rainfall, per 1,000 mm | 1,227 (9.3) | 0.53 (0.30–0.92) | 0.025 | |||
*PR, prevalence ratio; SES, socioeconomic status. Blank cells indicate that the variables were not included in the multivariable analyses due to lack of multivariable significance. †Results of univariable and multivariable Poisson regression adjusted for household clustering by using robust variance estimates. ‡Results of separate models for each of the covariates below. §Multivariable model, including only age, distance to nearest highway, and enhanced vegetation index as covariates. ¶SES rank, rank (from 0 [lowest] to 10 [highest]), according to socioeconomic score.