Table 1 Characteristics of study populations in Rufiji and Kilombero-Ulanga (KU) Demographic and Health Surveillance System sites, Tanzania, 2001, 2002, 2004, 2005, 2006 (N = 37,309)
| Â | 2001 | 2002 | 2004 | 2005 | 2006 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
|  | Rufiji (N = 1,521) n (%) | KU (N = 1,543) n (%) | Rufiji (N = 2,956) n (%) | KU (N = 3,885) n (%) | Rufiji (N = 3,715) n (%) | KU (N = 4,044) n (%) | Rufiji (N = 5,399) n (%) | KU (N = 4,902) n (%) | Rufiji (N = 4,190) n (%) | KU (N = 5,223) n (%) |
Median age in years (interquartile range) | 16 (6–39) | 19 (7–35) | 15 (6–36) | 17 (6–34) | 14 (5–35) | 15 (5–35) | 14 (5–35) | 15 (5–33) | 14 (5–34) | 15 (6–34) |
Age groups | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 <1 year old | 38 (2%) | 44 (3%) | 81 (3%) | 95 (2%) | 100 (3%) | 156 (4%) | 128 (2%) | 207 (4%) | 157 (4%) | 163 (3%) |
 1–4 years old | 229 (15%) | 209 (14%) | 453 (15%) | 628 (16%) | 639 (17%) | 652 (16%) | 957 (18%) | 820 (17%) | 675 (16%) | 781 (15%) |
 5–15 years old | 466 (31%) | 432 (28%) | 929 (31%) | 1115 (29%) | 1180 (32%) | 1201 (30%) | 1717 (32%) | 1473 (30%) | 1369 (33%) | 1629 (31%) |
 >15 years old | 788 (52%) | 858 (56%) | 1493 (51%) | 2035 (53%) | 1796 (48%) | 2035 (50%) | 2597 (48%) | 2402 (49%) | 1989 (47%) | 2618 (50%) |
Bed net use previous night | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Used untreated net | 235 (15%) | 911 (59%) | 437 (15%) | 2312 (60%) | 416 (11%) | 2063 (51%) | 911 (17%) | 2302 (47%) | 1430 (34%) | 2640 (51%) |
 Uses insecticide treated net | 42 (3%) | 145 (9%) | 70 (2%) | 395 (10%) | 370 (10%) | 1045 (26%) | 1197 (22%) | 1688 (34%) | 1300 (31%) | 1864 (36%) |
Socioeconomic status by asset index | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Poorest | 287 (19%) | 394 (26%) | 410 (17%) | 629 (17%) | 625 (17%) | 787 (19%) | 853 (16%) | 844 (17%) | 593 (14%) | 942 (18%) |
 Less poor | 163 (11%) | 224 (15%) | 337 (14%) | 715 (19%) | 823 (22%) | 624 (15%) | 1074 (20%) | 1004 (20%) | 816 (19%) | 998 (19%) |
 Middle | 281 (18%) | 332 (22%) | 496 (20%) | 804 (21%) | 805 (22%) | 766 (19%) | 1159 (21%) | 958 (20%) | 938 (22%) | 1048 (20%) |
 More rich | 416 (27%) | 249 (16%) | 589 (24%) | 830 (22%) | 726 (20%) | 984 (24%) | 1224 (23%) | 977 (20%) | 903 (22%) | 1125 (22%) |
 Least poor | 374 (25%) | 344 (22%) | 613 (25%) | 799 (21%) | 736 (20%) | 883 (22%) | 1089 (20%) | 1119 (23%) | 940 (22%) | 1079 (21%) |
Mean rainfall in previous 6 months from date of interview (in cm) | 61.3 | 44.2 | 96.4 | 198.4 | 74.5 | 149.0 | 67.6 | 146.1 | 93.3 | 136.1 |
Malaria burden | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Asexual parasitaemia | 400 (26%) | 274 (18%) | 828 (28%) | 851 (22%) | 696 (19%) | 1013 (25%) | 999 (19%) | 559 (11%) | 633 (15%) | 698 (13%) |
 Geometric mean asexual  parasite density (95% CL) | 886 (746,1052) | 1008 (830,1222) | 821 (736,916) | 1032 (923,1152) | 1104 (969,1259) | 992 (895,1100) | 1122 (1008,1248) | 727 (637,831) | 2144 (1837,2504) | 540 (482,605) |
 Gametocytaemia | 30 (2%) | 23 (1%) | 44 (1%) | 69 (2%) | 23 (1%) | 73 (2%) | 47 (1%) | 14 (<1%) | 14 (<1%) | 25 (<1%) |
 Geometric mean gametocyte  density (95% CL) | 66 (50,86) | 113 (69,186) | 104 (60,183) | 97 (76,123) | 76 (46,125) | 91 (74,113) | 67 (46,99) | 67 (38,121) | 224 (95,528) | 128 (48,343) |
 Gametocytemic patients  of parasitemic pts | 30/400 (7.5%) | 23/274 (8.4%) | 44/828 (5.3%) | 69/851 (8.1%) | 23/696 (3.3%) | 73/1013 (7.2%) | 47/999 (4.7%) | 14/559 (2.5%) | 14/633 (2.2%) | 25/698 (3.6%) |
Fever in prior two weeks | 301 (20%) | 227 (15%) | 339 (11%) | 571 (15%) | 377 (10%) | 421 (10%) | 756 (14%) | 484 (10%) | 457 (11%) | 462 (9%) |
Health seeking and anti-malarial use for febrile illness in prior two weeks | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Use of health facility | 89 (6%) | 57 (4%) | 115 (4%) | 187 (5%) | 160 (4%) | 107 (3%) | 299 (6%) | 163 (3%) | 130 (3%) | 193 (4%) |
 Use of any anti-malarial | 69 (5%) | 78 (5%) | 98 (3%) | 242 (6%) | 152 (4%) | 212 (5%) | 270 (5%) | 267 (5%) | 117 (3%) | 287 (6%) |
 Use of sulphadoxine-pyrimethamine only | 25 (2%) | 6 (<1%) | 65 (2%) | 144 (4%) | 41 (1%) | 104 (3%) | 36 (1%) | 120 (2%) | 42 (1%) | 136 (3%) |
 Use of artesunate-sulphadoxine-pyrimethamine | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 83 (2%) | 0 (0%) | 180 (3%) | 0 (0%) | 32 (1%) | 0 (0%) |
 Use of artesunate monotherapy | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 2 (<1%) | 0 (0%) | 5 (<1%) | 0 (0%) | 10 (<1%) | 0 (0%) |
 Use of other anti-malarial* | 44 (3%) | 72 (5%) | 33 (1%) | 98 (3%) | 27 (1%) | 108 (3%) | 52 (1%) | 147 (3%) | 33 (1%) | 151 (3%) |
Estimated number of anti-malarial treatments per 100 persons per year †|  |  |  |  |  |  |  |  |  |  |
 Any anti-malarial | 118 | 131 | 86 | 162 | 106 | 136 | 130 | 142 | 73 | 143 |
 Sulphadoxine-pyrimethamine only | 43 | 10 | 57 | 96 | 29 | 67 | 17 | 64 | 26 | 68 |
 Artesunate-sulphadoxine-pyrimethamine | 0 | 0 | 0 | 0 | 58 | 0 | 87 | 0 | 20 | 0 |
 Other anti-malarial* | 75 | 121 | 29 | 66 | 19 | 69 | 25 | 80 | 20 | 75 |