Table 2.
Association of malaria infection status with age, sex, LLINs, IRS, number of tests conducted per participant, geographical location, season and IRS insecticide used
| Category | DP % | N/N (I) | OR [95 % CI] | P |
|---|---|---|---|---|
| Overall | 21.7 | 31,974/147,257 (25,354) | 0.13 [0.08, 0.21] | <0.001 |
| Age | ||||
| <1 | 14.2 | 501/3535 (1735) | 1.26 [1.09, 1.45] | 0.001 |
| 1–4 | 24.0 | 6127/25,505 (5677) | 2.75 [2.54, 2.98] | <0.001 |
| 5–10 | 27.4 | 10,066/36,779 (7608) | 3.62 [3.35, 3.91] | <0.001 |
| 11–14 | 26.0 | 4892/18,840 (4746) | 3.36 [3.09, 3.65] | <0.001 |
| 15–24 | 20.3 | 4491/22,077 (5685) | 2.04 [1.88, 2.22] | <0.001 |
| 25–44 | 14.9 | 4028/27,044 (5807) | 1.24 [1.14, 1.34] | <0.001 |
| ≥45 | 13.8 | 1796/13,027 (2903) | 1 [NA] | NA |
| Sex | ||||
| Male | 23.3 | 16,068/79,208 (12,008) | 1 [NA] | NA |
| Female | 20.3 | 15,750/67,567 (13,228) | 0.86 [0.83, 0.90] | <0.001 |
| Interventions | ||||
| LLINs | 20.0 | 20,613/103,149 (20,706) | 0.89 [0.85, 0.93] | <0.001 |
| IRS | 17.4 | 7568/43,560 (9926) | 0.87 [0.82, 0.93] | <0.001 |
| Number of tests conducted per participant | 21.7 | 31,974/147,257(25,354) | 0.97 [0.97, 0.98] | <0.001 |
| Type of visit | ||||
| Passive | 43.4 | 6416/14,785 (8922) | 1 [NA] | NA |
| Active | 19.2 | 25,281/131,359 (22055) | 0.29 [0.28, 0.31] | <0.001 |
| Clusters | ||||
| Luangwa district | ||||
| Sinyawagora RHC | 19.7 | 1314/6655 (1959) | 2.86 [1.65, 4.97] | <0.001 |
| Kasinsa RHC | 16.7 | 2232/13,402 (3429) | 4.67 [2.78, 7.84] | <0.001 |
| Chitope RHC | 19.6 | 3419/17,463 (1215) | 2.92 [2.04, 4.17] | <0.001 |
| Luangwa High School RHC | 16.5 | 2854/17,320 (1158) | 7.37 [4.31, 12.61] | <0.001 |
| Mphuka RHC | 24.9 | 2981/11,957 (2147) | 7.37 [4.31, 12.61] | <0.001 |
| Mandombe RHC | 10.3 | 1386/13,508 (1805) | 1.54 [0.89, 2.66] | 0.119 |
| Luangwa Boma RHC | 6.4 | 839/13,161 (2033) | 1 [NA] | NA |
| Nyimba district | ||||
| Kacholola RHC | 26.7 | 3108/11,654 (1166) | 7.50 [4.75, 11.84] | <0.001 |
| Hofmeyer RHC | 41.9 | 2601/6214 (2120) | 15.81 [10.20, 24.52] | <0.001 |
| Mtilizi RHC | 37.6 | 2238/5949 (2024) | 12.35 [7.72, 19.76] | <0.001 |
| Mtilizi RHP | 25.3 | 2478/9788 (3379) | 13.49 [8.45, 21.56] | <0.001 |
| Chinambi RHC | 31.9 | 1740/5463 (1741) | 9.16 [5.79, 14.48] | <0.001 |
| Mkopeka RHC | 32.8 | 2761/8413 (1311) | 14.22 [8.55, 23.63] | <0.001 |
| Chipembe RHC | 32.1 | 2023/6310 (1916) | 13.54 [8.03, 22.84] | <0.001 |
| Season | ||||
| Hot & wet (Dec–April) | 25.3 | 18,283/72,217 (20,243) | 4.20 [3.67, 4.81] | <0.001 |
| Cool & dry (May–Aug) | 23.9 | 11,216/46,860 (16,513) | 3.25 [2.80, 3.76] | <0.001 |
| Hot & dry (Sept–Nov) | 8.7 | 2444/27,983 (12,590) | 1 [NA] | NA |
| Insecticide applied for IRS | ||||
| Deltamethrine | ||||
| 1–3 months since last spray | 13.3 | 322/2419 (2166) | 0.81 [0.65, 1.01] | 0.064 |
| 4–6 months since last spray | 23.8 | 2411/10,150 (4231) | 1.07 [0.94, 1.23] | 0.295 |
| 7–12 months since last spray | 13.6 | 2128/15,640 (4434) | 1.16 [1.03, 1.30] | 0.013 |
| Never sprayed and >13 months since last spray | 22.8 | 27,083/118,899 (23,233) | 1 [NA] | NA |
| Lambdacyhalothrin | ||||
| 1–3 months since last spray | 4.7 | 145/3102 (1526) | 0.69 [0.53, 0.90] | 0.006 |
| 4–6 months since last spray | 9.4 | 207/2199 (1264) | 1.26 [1.01, 1.57] | 0.042 |
| 7–12 months since last spray | 4.5 | 157/3508 (1469) | 0.94 [0.74, 1.21] | 0.653 |
| Never sprayed and >13 months since last spray | 22.7 | 31,435/138,299 (24,931) | 1 [NA] | NA |
| Primiphosmethyl EC | ||||
| 1–3 months since last spray | 18.9 | 1922/10,194 (5527) | 0.77 [0.69, 0.85] | <0.001 |
| 4–6 months since last spray | 28.8 | 2666/9259 (5926) | 0.64 [0.58, 0.71] | <0.001 |
| 7–12 months since last spray | 16.0 | 1793/11,184 (5760) | 0.63 [0.56, 0.71] | <0.001 |
| Never sprayed and >13 months since last spray | 21.9 | 25,563/11,6471 (22,311) | 1 [NA] | NA |
| Primiphosmethyl CS | ||||
| 1–3 months since last spray | 13.0 | 468/3590 (2675) | 0.37 [0.31, 0.43] | <0.001 |
| 4–6 months since last spray | 30.6 | 1386/4536 (3349) | 0.24 [0.21, 0.27] | <0.001 |
| 7–12 months since last spray | 49.5 | 95/192 (191) | 1.35 [0.85, 2.15] | 0.204 |
| Never sprayed and >13 months since last spray | 21.6 | 29,995/138,790 (24,588) | 1 [NA] | NA |
The association of malaria infection with age, sex, use of LLINs, use of IRS, geographical location (cluster), number of tests conducted per participant, season and insecticide used in IRS was determined using GLMM; with observed malaria RDT determined status as a binary dependent outcome with the independent categories of age, sex, access and use of LLINs or IRS, insecticide used in IRS, number of tested conducted per participant and seasons. The models included date and participant nested within CHW catchment nested within geographical location (cluster) as random effects except for one in which cluster was treated as a categorical variable to determine the effects of each cluster. The final model consisted of age, sex, access and use of LLINs or IRS, insecticide used in IRS, season, number of tests conducted per participant and geographical location as the determinants of malaria infection
DP RDT-determined diagnostic positivity, n Number RDT positive, N Total number tested by RDT, I Number of individuals that participated in RDT testing, OR Odds ratio, CI Confidence intervals, P Probability of the null hypothesis, NA Not applicable because reference group