Table 3 Prevalence of plasmodial infection in asymptomatic subjects according to farming systems (R0: no rice cultivation; R1: single rice cropping; R2: double rice cropping) and age groups
Plasmodium falciparum infection | Plasmodium malariae infection | Plasmodium ovale infection | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Asexual blood stages | Gametocytes | Asexual blood stages | Asexual blood stages | ||||||||
Agro-ecosystem | Age groups (years) | N | Positive thick blood smear | Prevalence rate (95% CI) | Geometric mean density (95% CI) | Positive thick blood smear | Prevalence rate (95% CI) | Positive thick blood smear | Prevalence rate (95% CI) | Positive thick blood smear | Prevalence rate (95% CI) |
R0 | 0–1 | 291 | 219 | 75.3 (70.4–80.1) | 903 (702–1162) | 33 | 11.3 (7.8–14.9) | 27 | 9.3 (5.9–12.6) | 3 | 1.0 (0.1–2.2) |
2–4 | 830 | 637 | 76.7 (71.8–81.7) | 578 (513–651) | 46 | 5.5 (3.6–7.5) | 72 | 8.7 (6.8–10.6) | 15 | 1.8 (0.9–2.7) | |
5–9 | 1,263 | 830 | 65.7(61.3670.1) | 237 (216–259) | 29 | 2.3 (1.5–3.1) | 45 | 3.6 (2.5–4.6) | 5 | 0.4 (0.0–0.7) | |
10–19 | 1,482 | 748 | 50.5 (45.5–55.4) | 134 (123–147) | 19 | 1.3 (0.7–1.9) | 27 | 1.8 (1.1–2.5) | 3 | 0.2 (0.0–0.4) | |
20–39 | 1,884 | 700 | 37.2 (32.6–41.7) | 93 (82–105) | 26 | 1.4 (0.9–1.9) | 10 | 0.5 (0.2–0.9) | 2 | 0.1 (0.0–0.3) | |
> = 40 | 2,439 | 806 | 33.0 (29.6–36.5) | 81 (69–94) | 18 | 0.7 (0.2–1.3) | 10 | 0.4 (0.2–0.7) | 0 | 0.0 (0.0–0.0) | |
Total | 8,189 | 3,940 | 48.1 (44.8–51.4) | 180 (165–195) | 171 | 2.1 (1.8–2.4) | 191 | 2.3 (2.0–2.7) | 28 | 0.3 (0.2–0.5) | |
R1 | 0–1 | 426 | 325 | 76.3 (70.3–82.3) | 843 (583–1220) | 33 | 7.7 (3.3–12.2) | 36 | 8.5 (5.8–11.1) | 8 | 1.9 (0.6–3.2) |
2–4 | 1,207 | 926 | 76.7 (74.0–79.4) | 669 (551–812) | 79 | 6.5 (4.7–8.4) | 95 | 7.9 (6.4–9.4) | 11 | 0.9 (0.4–1.4) | |
5–9 | 1,997 | 1,259 | 63.0 (59.3–66.8) | 225 (193–262) | 76 | 3.8 (2.2–5.4) | 46 | 2.3 (1.6–3.0) | 4 | 0.2 (0.0–0.4) | |
10–19 | 2,194 | 932 | 42.5 (38.0–47.0) | 120 (107–135) | 32 | 1.5 (0.7–2.3) | 12 | 0.5 (0.2–0.9) | 6 | 0.3 (0.1–0.5) | |
20–39 | 3,107 | 965 | 31.1 (27.4–34.7) | 81 (70–94) | 31 | 1.0 (0.5–1.5) | 12 | 0.4 (0.2–0.6) | 1 | 0.0 (0.0–0.1) | |
> = 40 | 2,089 | 545 | 26.1 (21.9–30.3) | 71 (59–86) | 20 | 1.0 (0.6–1.4) | 15 | 0.7 (0.4–1.1) | 0 | 0.0 (0.0–0.0) | |
Total | 11,020 | 4,952 | 44.9 (41.7–48.2) | 193 (194–219) | 271 | 2.5 (2.2–2.7) | 216 | 2.0 (1.7–2.2) | 30 | 0.3 (0.2–0.4) | |
R2 | 0–1 | 448 | 346 | 77.2 (73.4–81.1) | 943 (765–1163) | 40 | 8.9 (6.5–11.3) | 29 | 6.5 (4.2–8.8) | 5 | 1.1 (0.1–2.1) |
2–4 | 1,031 | 812 | 78.8 (76.5–81.1) | 614 (540–698) | 64 | 6.1 (4.9–7.3) | 78 | 7.6 (6.0–9.2) | 20 | 1.9 (1.1–2.8) | |
5–9 | 2,008 | 1,256 | 62.5 (60.4–64.7) | 243 (225–263) | 56 | 2.8 (2.1–3.5) | 35 | 1.7 (1.2–2.3) | 5 | 0.2 (0.0–0.5) | |
10–19 | 2,097 | 982 | 46.8 (44.5–49.1) | 137 (126–149) | 36 | 1.7 (1.2–2.3) | 16 | 0.8 (0.4–1.1) | 5 | 0.2 (0.0–0.4) | |
20–39 | 2,617 | 821 | 31.4 (29.7–33.7) | 91 (82–100) | 16 | 0.6 (0.3–0.9) | 9 | 0.3 (0.1–0.6) | 3 | 0.1 (0.0–0.2) | |
> = 40 | 1,920 | 555 | 28.9 (26.7–31.1) | 77 (71–84) | 10 | 0.5 (0.3–0.8) | 10 | 0.5 (0.2–0.8) | 1 | 0.1 (0.0–0.2) | |
Total | 10,121 | 4,772 | 47.1 (45.6–48.7) | 206 (194–219) | 222 | 2.2 (1.9–2.5) | 177 | 1.7 (1.5–2.0) | 39 | 0.4 (0.3–0.5) | |