Background
Methods
Study site and sampling
PCR and serology
Geographical information
Statistical analysis
Ethical considerations
Results
Characteristics of the study population
Altitude and malaria risk
1350–1449 m | 1450–1499 m | 1500–1549 m | 1550–1650 m | Total | |
---|---|---|---|---|---|
Number of participants (number of compounds) | 5424 (1108) | 6363 (1235) | 4579 (816) | 839 (140) | 17,503 (3213) |
Age, % (n/N) (years) | |||||
<5 | 26.4 (1429/5424) | 27.0 (1791/6636) | 27.1 (1239/4579) | 27.7 (232/839) | 26.9 (4701/17,503) |
6–10 | 18.9 (1024/5424) | 18.1 (1202/6636) | 18.0 (822/4579) | 19.4 (163/839) | 18.4 (3215/17,503) |
11–15 | 15.2 (823/5424) | 13.9 (923/6636) | 15.0 (685/4579) | 14.3 (120/839) | 14.6 (2552/17,503) |
16–25 | 13.7 (744/5424) | 15.3 (1018/6636) | 14.8 (677/4579) | 16.5 (138/839) | 14.7 (2579/17,503) |
>26 | 25.9 (1404/5424) | 25.7 (1702/6636) | 25.3 (1156/4579) | 22.2 (186/839) | 25.5 (4456/17,503) |
Fever, % temperature > 37.5 °C, % (n/N) | 4.0 (216/5423) | 3.1 (204/6631) | 2.5 (116/4575) | 1.3 (11/839) | 3.1 (547/17,468) |
Clinical malaria, % (n/N)a
| 2.3 (126/5423) | 1.8 (120/6631) | 1.1 (48/4575) | 0.12 (1/839) | 1.7 (295/17,468) |
Parasite prevalence, % PCR positive (n/N) | 27.2 (1111/4083) | 19.6 (900/4599) | 16.7 (592/3548) | 8.1 (54/664) | 20.6 (2663/12,912) |
Antibody prevalence, % positive (n/N)b
| 62.6 (3108/4967) | 58.0 (3623/6252) | 48.3 (2104/4361) | 31.7 (246/777) | 55.5 (9092/16,381) |
Anaemia, % (n/N) | |||||
Severe (<6 g/dL) | 0.6 (30/5282) | 0.7 (46/6391) | 0.4 (19/4366) | 0.2 (2/818) | 0.6 (97/16,878) |
Moderate (<8 g/dL) | 3.1 (163/5282) | 3.4 (214/6391) | 2.6 (112/4336) | 2.0 (16/818) | 3.0 (505/16,878) |
Mild (<11 g/dL) | 26.0 (1374/5282) | 23.0 (1472/6391) | 21.5 (938/4336) | 20.2 (165/818) | 23.4 (3954/16,878) |
Micro-epidemiological patterns in malaria transmission intensity
Parasite prevalence | Antibody prevalence | |||
---|---|---|---|---|
ORa
| Adjusted OR (95 % CI)a
| ORa
| Adjusted OR (95 % CI)a
| |
Individual characteristics | ||||
Age ( years) | ||||
≤5 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
6–10 | 1.27 (1.13–1.42) | 1.26 (1.10–1.46) | 1.88 (1.71–2.06) | 2.35 (2.10–2.63) |
11–15 | 1.22 (1.07–1.39) | 1.25 (1.08–1.47) | 3.51 (3.17–3.89) | 4.70 (4.15–5.33) |
16–25 | 0.92 (0.81–1.04) | 0.89 (0.76–1.04) | 4.57 (4.13–5.07) | 6.57 (5.79–7.46) |
≥26 | 0.64 (0.57–0.73) | 0.61 (0.53–0.71) | 4.33 (3.97–4.72) | 6.05 (5.43–6.73) |
Bed net use | 0.79 (0.71–0.88) | 0.82 (0.72–0.93) | 0.85 (0.79–0.93) | 0.89 (0.81–0.98) |
House structure | ||||
Mud wall | 1.46 (1.25–1.71) | 1.26 (1.05–1.50) | 1.14 (1.03–1.27) | |
Open eaves | 1.25 (1.10–1.41) | 1.16 (1.01–1.34) | 1.28 (1.17–1.39) | 1.33 (1.21–1.46) |
Environment | ||||
Distance to water | ||||
<250 m | 1 (reference) | 1 (reference) | 1 (reference) | |
250–500 m | 1.04 (0.89–1.22) | 0.97 (0.87–1.09) | 1.04 (0.92–1.19) | |
500–999 m | 0.83 (0.71–0.96) | 0.66 (0.59–0.74) | 0.91 (0.80–1.03) | |
1000 m+ | 0.78 (0.62–0.98) | 0.44 (0.38–0.52) | 0.81 (0.67–0.97) | |
Altitude (m) | ||||
1350–1449 | 1 (reference) | 1 (reference) | 1 (reference) | 1 (reference) |
1450–1499 | 0.63 (0.55–0.72) | 0.84 (0.72–0.98) | 0.83 (0.75–0.91) | 0.90 (0.81–1.01) |
1500–1549 | 0.52 (0.45–0.61) | 0.68 (0.56–0.81) | 0.57 (0.51–0.64) | 0.79 (0.69–0.89) |
1550–1650 | 0.25 (0.17–0.37) | 0.43 (0.28–0.66) | 0.28 (0.23–0.35) | 0.71 (0.56–0.90) |
Parasite prevalence 500 m radius | 1.06 (1.05–1.06) | 1.07 (1.06–1.07) | 1.03 (1.02–1.03) | |
Antibody prevalence 500 m radius | 1.02 (1.02–1.03) | 1.04 (1.03–1.04) | 1.04 (1.03–1.04) | |
TWI (minimum) | 1.91 (1.70–2.16) | 1.23 (1.06–1.41) | ||
TWI (mean) | 2.16 (1.94–2.41) | |||
TWI (maximum) | 1.03 (1.01–1.05) | 0.97 (0.95–1.00) | 1.09 (1.07–1.10) |