Background
Methods
Study area and population
Study design
Data collection
Laboratory procedures
Microscopy
Molecular testing for malaria parasitaemia by PCR
Serology
Statistical analysis
Results
Socio-demographic and household characteristics
Characteristics |
P. vivax PRBC-PCR |
P. falciparum PRBC-PCR | Total n = 450 (%) | ||||
---|---|---|---|---|---|---|---|
Positive n = 113 (%) | Negative n = 337 (%) | p value | Positive n = 22 (%) | Negative n = 428 (%) | p value | ||
Study area | 0.146* | 0.371 | |||||
Cahuide | 77 (68.1) | 203 (60.2) | 16 (72.7) | 264 (61.7) | 280 (62.2) | ||
Lupuna | 36 (31.9) | 134 (39.8) | 6 (27.3) | 164 (38.3) | 170 (37.8) | ||
Sex | 0.191* | 0.195* | |||||
Male | 58 (51.3) | 148 (43.9) | 7 (31.8) | 199 (46.5) | 206 (45.8) | ||
Female | 55 (48.7) | 189 (56.1) | 15 (68.2) | 229 (53.5) | 244 (54.2) | ||
Age groups (years) | 0.001** | 0.022** | |||||
< 10 | 24 (21.2) | 119 (35.3) | 2 (9.1) | 141 (32.9) | 143 (31.8) | ||
10–29.9 | 41 (36.3) | 133 (39.5) | 9 (40.9) | 165 (38.6) | 174 (38.7) | ||
≥ 30 | 48 (42.5) | 85 (25.2) | 11 (50.0) | 122 (28.5) | 133 (29.6) | ||
Education | 0.243 | 0.503 | |||||
None | 10 (8.8) | 51 (15.1) | 1 (4.6) | 60 (14.0) | 61 (13.6) | ||
Primary school | 67 (59.3) | 183 (54.3) | 14 (63.6) | 236 (55.1) | 250 (55.6) | ||
Secondary school or higher | 36 (31.9) | 103 (30.6) | 7 (31.8) | 132 (30.8) | 139 (30.9) | ||
Occupation (> 18 years old) | 0.424 | 0.756 | |||||
Logger or charcoal worker | 6 (9.0) | 8 (5.8) | 2 (13.3) | 12 (6.3) | 14 (6.9) | ||
Farmer | 19 (28.4) | 30 (21.9) | 3 (20.0) | 46 (24.3) | 49 (24.0) | ||
Trader | 4 (6.0) | 8 (5.8) | 0 (0.0) | 12 (6.3) | 12 (5.9) | ||
Others | 10 (14.9) | 15 (11.0) | 2 (13.3) | 23 (12.2) | 25 (12.2) | ||
None | 28 (41.8) | 76 (55.5) | 8 (53.3) | 96 (50.8) | 104 (51.0) | ||
Time in community (years) | 0.071* | 0.209 | |||||
≤ 2 | 24 (21.8) | 45 (14.2) | 5 (26.3) | 64 (15.7) | 69 (16.2) | ||
> 2 | 86 (78.2) | 272 (85.8) | 14 (73.7) | 344 (84.3) | 358 (83.8) | ||
Mammal-livestock | 0.443 | 1.000 | |||||
Yes | 60 (53.1) | 194 (57.6) | 12 (54.5) | 242 (56.5) | 254 (56.4) | ||
No | 53 (46.9) | 143 (42.4) | 10 (45.5) | 186 (43.5) | 196 (43.6) | ||
Avian-livestock | 0.724 | 1.000 | |||||
Yes | 77 (68.1) | 236 (70.0) | 15 (68.2) | 298 (69.6) | 313 (69.6) | ||
No | 36 (31.9) | 101 (30.0) | 7 (31.8) | 130 (30.4) | 137 (30.4) | ||
Impregnated bed nets | 0.048** | 1.000 | |||||
Yes | 75 (66.4) | 257 (76.3) | 16 (72.7) | 316 (73.8) | 332 (73.8) | ||
No | 38 (33.6) | 80 (23.7) | 6 (27.3) | 112 (26.2) | 118 (26.2) |
Malaria parasite prevalence and exposure
Characteristics |
P. vivax PRBCs PCR |
P. falciparum PRBCs PCR | Total n = 450 (%) | ||||
---|---|---|---|---|---|---|---|
Positive n = 113 (%) | Negative n = 337 (%) | p value | Positive n = 22 (%) | Negative n = 428 (%) | p value | ||
Positive PCR to P. vivax in previous month (Dec 2012) | 0.017** | 0.764 | |||||
Yes | 26 (23.0) | 45 (13.4) | 4 (18.2) | 67 (15.6) | 71 (15.8) | ||
No | 87 (77.0) | 292 (86.6) | 18 (81.8) | 361 (84.4) | 379 (84.2) | ||
Positive PCR to P. falciparum in previous month (Dec 2012) | 1.000 | 0.081* | |||||
Yes | 2 (1.8) | 8 (2.4) | 2 (9.1) | 8 (1.9) | 10 (2.2) | ||
No | 111 (98.2) | 329 (97.6) | 20 (90.9) | 420 (98.1) | 440 (97.8) | ||
Seropositivity to P. vivax (Jan 2013) | 0.004** | 0.221 | |||||
Yes | 44 (38.9) | 82 (24.3) | 9 (40.9) | 117 (27.3) | 126 (28.0) | ||
No | 69 (61.1) | 255 (75.7) | 13 (59.1) | 311 (72.7) | 324 (72.0) | ||
Seropositivity to P. falciparum (Jan 2013) | 0.022** | 0.340 | |||||
Yes | 41 (36.3) | 84 (24.9) | 8 (36.4) | 117 (27.3) | 125 (27.8) | ||
No | 72 (63.7) | 253 (75.1) | 14 (63.6) | 311 (72.7) | 325 (72.2) | ||
Positive microscopy to P. vivax (Jan 2013) | < 0.001** | 1.000 | |||||
Yes | 14 (12.4) | 2 (0.6) | 0 (0.00) | 16 (3.7) | 16 (3.6) | ||
No | 99 (87.6) | 335 (99.4) | 22 (100.0) | 412 (96.3) | 434 (96.4) | ||
Positive microscopy to P. falciparum (Jan 2013) | 1.000 | 0.049** | |||||
Yes | 0 (0.0) | 1 (0.3) | 1 (4.5) | 0 (0.00) | 1 (0.2) | ||
No | 113 (100.0) | 336 (99.7) | 21 (95.5) | 428 (100.0) | 449 (99.8) | ||
Fever a
| 0.247 | 0.185* | |||||
Yes | 6 (5.4) | 10 (3.0) | 2 (9.1) | 14 (3.3) | 16 (3.6) | ||
No | 105 (94.6) | 322 (97.0) | 20 (90.9) | 407 (96.7) | 427 (96.4) | ||
Malaria treatment previous month | 1.000 | 0.015** | |||||
Yes | 5 (4.4) | 16 (4.7) | 4 (18.2) | 17 (4.0) | 21 (4.7) | ||
No | 108 (95.6) | 321 (95.3) | 18 (81.8) | 411 (96.0) | 429 (95.3) |
Parasite density analysis
P.vivax
|
P. falciparum
| |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Univariate | Multivariate | Univariate | Multivariate | |||||||||
Coeff | 95% CI | p value | Coeff | 95% CI | p value | Coeff | 95% CI | p value | Coeff | 95% CI | p value | |
Study area (Ref = Cahuide) | ||||||||||||
Lupuna | − 1.19 | (− 2.37: − 0.01) | 0.048* | 0.99 | (− 1.18:3.16) | 0.371 | − 4.6 | (− 7.17: − 2.03) | < 0.001* | 0.49 | (− 0.96:1.95) | 0.509 |
Age groups (Ref = < 10 years) | ||||||||||||
10–29.9 | 0.93 | (− 0.59:2.46) | 0.230 | 0.46 | (− 1.31:2.24) | 0.606 | 1.08 | (− 2.47:4.64) | 0.550 | 1.10 | (− 2.06:4.26) | 0.495 |
≥ 30 | 0.57 | (− 0.91:2.05) | 0.449 | − 0.28 | (− 2.58:2.03) | 0.814 | 8.28 | (4.79:11.78) | < 0.001* | 1.90 | (− 1.36:5.15) | 0.254 |
Time in community (Ref = > 2 years) | ||||||||||||
≤ 2 | 1.67 | (0.39:2.94) | 0.010* | 3.11 | (1.50:4.71) | <0.001* | − 6.99 | (− 9.66: − 4.32) | < 0.001* | − 0.68 | (− 2.26:0.90) | 0.401 |
Fever (Ref = No) | ||||||||||||
Yes | 2.94 | (0.72:5.16) | 0.009* | 4.14 | (1.12:7.17) | 0.007* | 7.55 | (4.92:10.18) | < 0.001* | 6.36 | (4.28:8.43) | < 0.001* |
Seropositivity to species-specific (Ref = No) | ||||||||||||
Yes | 8.40 | (6.71:10.09) | <0.001* | − 0.46 | (− 2.24:1.31) | 0.608 | 8.61 | (7.00:10.23) | < 0.001* | 3.11 | (1.66:4.56) | < 0.001* |
Multilevel analysis for malaria infection
P. vivax
|
P. falciparum
| |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Univariate | Multivariate | Univariate | Multivariate | |||||||||
OR | 95% CI | p value | AOR | 95% CI | p value | OR | 95% CI | p value | AOR | 95% CI | p value | |
Null model | < 0.001 | < 0.001 | < 0.001 | |||||||||
Constant | 0.33 | (0.24–0.44) | < 0.001 | 0.13 | (0.07–0.26) | 0.07 | (0.02:0.18) | 0.01 | (0.00:0.04) | |||
Study area (Ref = Cahuide) | ||||||||||||
Lupuna | 0.66 | (0.40:1.11) | 0.121 | 0.55 | (0.21:1.44) | 0.223 | ||||||
Sex (Ref = Male) | ||||||||||||
Female | 0.75 | (0.47:1.21) | 0.239 | 1.75 | (0.68:4.50) | 0.242 | ||||||
Age groups (Ref = < 10 years) | ||||||||||||
10–29.9 | 1.81 | (0.95:3.46) | 0.070 | 1.73 | (0.89:3.35) | 0.103 | 4.47 | (0.90:22.17) | 0.067 | 10.72 | (1.26:91.13) | 0.030* |
> = 30 | 3.74 | (1.88: 7.43) | < 0.001* | 3.31 | (1.60:6.85) | 0.001* | 9.71 | (1.83:51.52) | 0.008* | 16.32 | (1.93:138.22) | 0.010* |
Education (Ref = None) | ||||||||||||
Primary school | 2.26 | (1.00:5.11) | 0.050* | 4.20 | (0.53:33.22) | 0.174 | ||||||
Secondary school or higher | 2.22 | (0.91:5.40) | 0.077 | 3.65 | (0.43:30.78) | 0.234 | ||||||
Occupation (Ref = Not a Logger, Charcoal worker or Farmer) | ||||||||||||
Yes | 1.70 | (0.77: 3.75) | 0.189 | 1.35 | (0.43:4.24) | 0.609 | ||||||
Time in community (Ref = > 2 years) | ||||||||||||
≤ 2 | 1.86 | (0.97:3.55) | 0.061 | 2.07 | (1.03: 4.16) | 0.042* | 2.30 | (0.79:6.74) | 0.128 | 2.75 | (0.88:8.59) | 0.082 |
Mammal-livestock (Ref = No) | ||||||||||||
Yes | 0.83 | (0.51:1.36) | 0.459 | 0.88 | (0.36:2.13) | 0.776 | ||||||
Avian-livestock (Ref = No) | ||||||||||||
Yes | 0.91 | (0.53:1.54) | 0.722 | 0.91 | (0.36:2.33) | 0.847 | ||||||
Impregnated bed nets (Ref = No) | ||||||||||||
Yes | 0.60 | (0.35:1.01) | 0.054 | 0.82 | (0.30:2.19) | 0.689 | ||||||
Fevera (Ref = No) | ||||||||||||
Yes | 2.90 | (0.80:10.56) | 0.105 | 4.01 | (0.69:23.20) | 0.120 | 5.96 | (0.98:36.18) | 0.052 | |||
Seropositivity to species-specific (Ref = No) | ||||||||||||
Yes | 2.25 | (1.34:3.78) | 0.002* | 1.82 | (1.03: 3.20) | 0.038* | 1.80 | (0.72:4.47) | 0.206 | |||
Positive PCR to species-specific in previous month (Ref = No) | ||||||||||||
Yes | 2.07 | (1.14:3.80) | 0.018* | 5.46 | (0.88:33.72) | 0.067 | 10.40 | (1.52:71.08) | 0.017* | |||
Malaria treatment previous month (Ref = No) | ||||||||||||
Yes | 1.09 | (0.34:3.48) | 0.888 | 5.61 | (1.64:19.15) | 0.006* |
Var | ICC | MOR | |||
---|---|---|---|---|---|
Est. | 95% CI | Est. | 95% CI | ||
P. vivax
| |||||
Null model | 0.7050 | (0.2811:1.7686) | 0.1313 | (0.0235:0.4874) | 1.9593 |
Adjusted model | 0.7747 | (0.2982:2.0131) | 0.1543 | (0.0263:0.5519) | 2.0938 |
P. falciparum
| |||||
Null model | 0.3465 | (0.0001:1857.645) | 0.0352 | (0:1.0000) | 1.3916 |
Adjusted model | 0 | (−) | 0 | (−) | 1.0000 |