Table 2.
Household risk factors for human biting rate in Nagongera, Uganda, before and after the introduction of indoor residual spraying
|
Before indoor residual spraying (Oct 1, 2011, to Jan 31, 2015) |
After indoor residual spraying (Feb 1, 2015, to June 30, 2017) |
||||||
|---|---|---|---|---|---|---|---|
| HBR* (total collection nights) | IRR†(95% CI) | p value | HBR* (total collection nights) | IRR†(95% CI) | p value | ||
| 2013 household data | |||||||
| Wealth index tertile | |||||||
| Poorest | 38·3 (1275) | 1 (ref) | ·· | 3·2 (965) | 1 (ref) | ·· | |
| Middle | 32·6 (1249) | 0·88 (0·67–1·16) | 0·37 | 2·9 (828) | 0·89 (0·61–1·32) | 0·57 | |
| Least poor | 27·2 (1224) | 0·72 (0·55–0·95) | 0·02 | 1·8 (687) | 0·51 (0·34–0·75) | 0·001 | |
| Main roof material | |||||||
| Thatched | 42·3 (1431) | 1 (ref) | ·· | 3·6 (979) | ·· | ·· | |
| Tiles or metal | 28·4 (2427) | 0·62 (0·49–0·78) | <0·0001 | 2·0 (1501) | 0·57 (0·41–0·80) | 0·001 | |
| Main wall material | |||||||
| Mud | 37·8 (2984) | 1 (ref) | ·· | 3·0 (2033) | 1 (ref) | ·· | |
| Cement, wood, or metal | 18·9 (874) | 0·48 (0·37–0·61) | <0·0001 | 1·1 (447) | 0·34 (0·23–0·50) | <0·0001 | |
| Eaves | |||||||
| Open | 41·2 (1829) | 1 (ref) | ·· | 3·1 (1252) | 1 (ref) | ·· | |
| Closed | 26·7 (2029) | 0·61 (0·49–0·76) | <0·0001 | 2·2 (1228) | 0·71 (0·51–1·00) | 0·05 | |
| 2016 household data | |||||||
| Wealth index tertile | |||||||
| Poorest | 41·2 (1085) | 1 (ref) | ·· | 3·0 (841) | 1 (ref) | ·· | |
| Middle | 30·2 (1128) | 0·76 (0·57–1·03) | 0·07 | 2·5 (796) | 0·84 (0·55–1·27) | 0·40 | |
| Least poor | 29·5 (1070) | 0·75 (0·55–1·01) | 0·05 | 2·4 (787) | 0·79 (0·52–1·19) | 0·26 | |
| Main roof material | |||||||
| Thatched | 44·0 (870) | 1 (ref) | ·· | 3·8 (659) | 1 (ref) | ·· | |
| Tiles or metal | 29·8 (2413) | 0·68 (0·52–0·89) | 0·005 | 2·2 (1765) | 0·58 (0·40–0·84) | 0·004 | |
| Main wall material | |||||||
| Mud | 39·7 (1616) | 1 (ref) | ·· | 3·7 (1217) | 1 (ref) | ·· | |
| Cement, wood, or metal | 27·6 (1667) | 0·70 (0·55–0·88) | 0·003 | 1·6 (1207) | 0·44 (0·33– 0·60) | <0·0001 | |
| Eaves | |||||||
| Open | 42·3 (1084) | 1 (ref) | ·· | 3·5 (824) | 1 (ref) | ·· | |
| Closed | 29·3 (2199) | 0·70 (0·55–0·91) | 0·007 | 2·2 (1600) | 0·64 (0·45–0·90) | 0·01 | |
| All household data | |||||||
| House typeठ| |||||||
| Traditional (2013 and 2016) | 38·8 (1712) | 1 (ref) | ·· | 3·5 (1295) | 1 (ref) | ·· | |
| Traditional (2013) and modern (2016) | 33·5 (958) | 0·90 (0·69–1·19) | 0·48 | 2·0 (693) | 0·55 (0·39–0·79) | 0·001 | |
| Modern (2013 and 2016) | 18·7 (573) | 0·52 (0·36–0·73) | 0·0002 | 1·0 (407) | 0·27 (0·17–0·42) | <0·0001 | |
*
Human biting rate (HBR) is the number of adult female Anopheles collected per house per night (total adult female Anopheles caught/total nights of collection).
†
IRR=incidence rate ratio.
‡
Modern houses were defined as those with a cement, wood, or metal wall, tiled or metal roof, and closed eaves; all other houses were defined as traditional; IRR for house type was adjusted for household socioeconomic position.
§
Before indoor residual spraying, IRR adjusted for 2013 household socioeconomic position and after indoor residual spraying, IRR adjusted for 2016 household socioeconomic position.