Background
Methods
Study area and population
Data collection
Sampling for cross-sectional surveys and assembling of the cohort study
Cross-sectional surveys of malaria parasitaemia and anaemia
Cohort study for active and passive case detection of malaria
Statistical analysis
Prevalence of parasitaemia and anaemia
Incidence of malaria
Risk factor analysis
Ethical approval
Results
Prevalence of parasitaemia and anaemia
Malaria indicators | October | July | ||||
---|---|---|---|---|---|---|
Binko | Carrière | p | Binko | Carrière | p | |
n = 255 | n = 221 | n = 473 | n = 196 | |||
Prevalence of parasitemia, n (%) | 76 (29.8) | 107 (52) | <0.01 | 113 (23.8) | 35 (18.9) | 0.15 |
Prevalence of symptomatic malaria, n (%) | 7 (9.2) | 17 (15.9) | <0.01 | 5 (4.4) | 5 (4.3) | 0.14 |
Parasite species, n (%) | ||||||
P. falciparum
| 72 (94.7) | 107 (94.0) | 0.63 | 108 (95.6) | 33 (89.2) | 0.15 |
P. falciparum + P. malariae
| 4 (5.3) | 8 (6.0) | 5 (4.4) | 4 (10.8) | ||
P. falciparum density (parasites/µl) n (%) | ||||||
1 to 1000 | 44 (57.9) | 50 (46.7) | <0.01 | 108 (95.6) | 30 (85.7) | 0.01 |
1001 to 5000 | 20 (26.3) | 31(29.0) | 0.84 | 5 (4.4) | 4 (11.4) | 0.12 |
>5000 | 12 (15.8) | 26 (24.3) | 0.16 | 0 (0.0) | 1 (2.9) | 0.24 |
P. falciparum geometric mean per µl (IQR) | 50 (24–77) | 35 (14–37) | 0.2 | 108 (72–117) | 271 (81–362) | 0.01 |
Gametocyte carriers (%) | 7.8 | 6.8 | 0.89 | 1.9 | 6.7 | <0.01 |
Anemia, n (%) | ||||||
Mild anemia (7.5 g/dl < hb < 9.5) | 47 (18.4) | 60 (27.2) | 0.02 | 77 (16.2) | 32 (16.6) | 0.98 |
Severe anemia (hb < 7.5 g/dl) | 25 (9.8) | 16 (7.2) | 0.32 | 22 (4.7) | 7 (3.6) | 0.53 |
Total prevalence of anemia | 72 (28.2) | 76 (34.4) | 0.14 | 99 (20.9) | 39 (20.2) | 0.99 |
Age groups (years) | October | Mantel–Haenszel OR 95 CI | July | Mantel–Haenszel OR 95 CI | ||
---|---|---|---|---|---|---|
Binko | Carrière | Binko | Carrière | |||
n (%) | n (%) | n (%) | n (%) | |||
<5 | 28 (23.7) | 39 (37.5) | 2.3 (1.6–3.4) | 41 (14.4) | 14 (37.6) | 3.7 (2.6–5.5) |
5 and + | 52 (32.7) | 73 (62.4) | 71 (10.4) | 21 (34.4) |
Demographic characteristics of the cohort study population
Binko (n = 296) | Carrière (n = 253) | p value | |
---|---|---|---|
Mean age in year (SD) | 3.9 (2.1) | 3.6 (2.2) | 0.05 |
Sex (male %) | 57.4 | 47.4 | 0.03 |
Age groups in years | |||
Less than 5 years old | 200 (67.5) | 186 (73.5) | <0.001 |
5 to 9 years old | 96 (32.5) | 67 (26.5) | |
Education level of parents/guardians (%) (years) | |||
None | 152 (51.4) | 140 (55.3) | 0.14 |
<9 | 96 (32.4) | 81 (32.0) | |
9–12 | 37 (12.5) | 30 (11.9) | |
More than 12 | 11 (3.7) | 2 (0.8) | |
Household socio economic status (%) | |||
Below rural poverty line | 58 (72.5) | 43 (70.4) | 0.86 |
Above rural poverty line | 22 (27.5) | 18 (29.6) |
Incidence of acute malaria and anaemia
Binko | Carrière n = 253 | p value | |
---|---|---|---|
n = 296 | |||
Cumulative malaria incidence, % | |||
Mild malaria | 55.1 | 42.7 | 0.07 |
Severe malaria | 10.6 | 13 | 0.25 |
Episodes of acute malaria per child (%) | |||
0 | 83 (28.0) | 89 (30.1) | 0.29 |
1 | 102 (34.7) | 95 (32.1) | |
2–3 | 40 (13.5) | 23 (7.8) | |
4–5 | 1 (0.3) | 2 (0.7) | |
Identified parasite species in malaria cases, % | |||
P. falciparum
| 91.9 | 88.6 | 0.26 |
P. malariae
| 1.9 | 7.5 | |
P. falciparum + P. malariae
| 6.2 | 3.9 | |
Geometric mean for P. falciparum (IQR) | 137 (40–259) | 169 (62–315) | 0.65 |
P. falciparum density per µl (%) | |||
1–1000 | 70.8 | 68.4 | 0.7 |
1001–5000 | 19.1 | 12.5 | 0.24 |
>5000 | 10.1 | 19.1 | 0.07 |
Anemia prevalence (%) | |||
Mild anemia (7.5 g/dl < hb < 11) | 45.3 | 47.8 | 0.83 |
Severe anemia (hb < 7.5 g/dl) | 15.9 | 15.4 | |
Total anemia prevalence | 61.2 | 63.2 |
Age groups (years) | Binko (n = 296) | Carrière (n = 256) | ||||
---|---|---|---|---|---|---|
n | Incidence per 100 | RR | n | Incidence per 100 | RR | |
<5 | 200 | 19.5 | 0.4 (0.3–0.4) | 189 | 14.9 | 0.3 (0.2–0.4) |
5+ | 96 | 54.2 | 67 | 52.5 |
Risk factors for acute malaria
Risk factors | Category | OR | 95 % CI | p |
---|---|---|---|---|
Malaria infection at enrolment (Ref: malaria positive) | – | 0.1 | (0.08–0.2) | <0.01 |
Age groups (Ref: age 5–9 years) | <0.01 | |||
0–1 | 0.4 | (0.2–0.8) | 0.02 | |
1–2 | 0.1 | (0.3–0.8) | 0.01 | |
2–4 | 0.9 | (0.6–1.6) | 0.85 | |
Household socioeconomic status (Ref: above national poverty line) | – | 3.2 | (2.1–4.8) | <0.01 |