Background
Methods
Study area and study design
Results
Rainy seasons | October 2000 | October 2009 | October 2010 | October 2011 |
---|---|---|---|---|
Number of participants | 1561 | 402 | 256 | 219 |
Median age (IQR) [years] | 14 (6–30) | 11 (5–28) | 15 (9–37) | 13 (6–33) |
Age range [years] | 0-90 | 1-89 | 1-90 | 1-74 |
Proportion of male participants [%] | 50.5 | 46.5 | 53.1 | 48.4 |
Parasite prevalence microscopy [%] (CI95%) | 78.9 (76.8-80.9) | 58.4 (53.4-63.2) | 55.90 (49.5-62.0) | 49.3 (42.5-56.1) |
Parasite prevalence PCR [%] (CI 95%) | 92.0 (87.4-95.4)
*
| 66.1 (61.1-70.7)
1
| 68.8 (62.7-74.4)
1
| 73.7 (67–79.7)
2
|
Number of symptomatic patients [%]** | 14.7 | 9.8 | 15.1 | |
Dry seasons
|
April 2010
|
April 2011
|
April 2012
| |
Number of participants | 362 | 267 | 261 | |
Median age (IQR) [years] | 14 (5–34) | 15 (7–33) | 13 (7–37) | |
Age range [years] | 1-78 | 0-77 | 1-78 | |
Proportion of male participants [%] | 44.8 | 44.9 | 45.6 | |
Parasite prevalence microscopy [%] (CI95%) | 30.1 (25.4-35.1) | 29.6 (24.1-35.5) | 32.6 (26.9-38.6) | |
Parasite prevalence PCR [%] (CI95%) | 39.4 (33.6-45.4)
1
| 39.3 (33.4-45.5)
1
| 34.6 (28.8-40.7) 2 | |
Number of symptomatic patients [%]** | 4.6 | 1.3 | 3.8 | |
Combined estimates
|
Combined rainy seasons 2009-2011
|
Combined data dry seasons 2010-2012
| ||
Number of participants | 877 | 890 | ||
Median age (IQR) [years] | 13 (6–31) | 14 (6–35) | ||
Age range [years] | 0-90 | 0-78 | ||
Proportion of male participants [%] | 48.9 | 45.0 | ||
Parasite prevalence microscopy [%] (CI95%) | 55.4 (51.9-58.6) | 30.7 (27.5-33.7) | ||
Parasite prevalence PCR [%] (CI95%) | 68.7 (65.4-71.8) | 37.9 (34.7-41.2) | ||
Number of symptomatic patients [%]** | 13.2 | 3.2 |
Parasite prevalence and density over time and comparing dry season and wet season
Plasmodium species distribution
Asymptomatic malaria and frequency of fever
% asymptomatic carriers/total carriers | 1-1,000 parasites/μl | 1,000-2,500 parasites/μl | 2,500-5,000 parasites/μl | 5,000-10,000 parasites/μl | > 10,000 parasites/μl | |
---|---|---|---|---|---|---|
Rainy season
| ||||||
0-4 years
| 68.1 (64/94) | 80.6 (25/31) | 61.5 (8/13) | 75.0 (9/12) | 76.5 (13/17) | 42.9 (9/21) |
(% asymptomatic carriers/total carriers) | ||||||
5-14 years
| 72.6 (170/234) | 75.9 (101/133) | 80.5 (33/41) | 69.0 (20/29) | 55.6 (10/18) | 46.2 (6/13) |
(% asymptomatic carriers/total carriers) | ||||||
15-44 years
| 86.4 (108/125) | 86.8 (92/106) | 81.8 (9/11) | 100 (4/4) | (3/3) | (0/1) |
(% asymptomatic carriers/total carriers) | ||||||
>45 years
| 86.2 (25/29) | 84.6 (22/26) | (2/2) | (0/0) | (0/0) | (1/1) |
(% asymptomatic carriers/total carriers) | ||||||
All
| 76.1 (367/482) | 81.1 (240/296) | 77.6 (52/67) | 73.3 (33/45) | 68.4 (26/38) | 44.4 (16/36) |
(% asymptomatic carriers/total carriers) | ||||||
Dry season
| ||||||
0-4 years
| 92.5 (49/53) | 90.9 (40/44) | (2/2) | 100 (4/4) | (2/2) | (1/1) |
(% asymptomatic carriers/total carriers) | ||||||
5-14 years
| 93.2 (136/146) | 94.0 (109/116) | 100 (17/17) | 83.3 (5/6) | 100 (4/4) | (1/3) |
(% asymptomatic carriers/total carriers) | ||||||
15-44 years
| 96.3 (52/54) | 96.0 (48/50) | (3/3) | (1/1) | (0/0) | (0/0) |
(% asymptomatic carriers/total carriers) | ||||||
>45 years
| 100 (16/16) | 100 (15/15) | (1/1) | (0/0) | (0/0) | (0/0) |
(% asymptomatic carriers/total carriers) | ||||||
All
| 94.1 (253/269) | 94.2 (212/225) | 100 (23/23) | 90.9 (10/11) | 100 (6/6) | 50 (2/4) |
(% asymptomatic carriers/total carriers) |
Univariate | Multivariate | |||
---|---|---|---|---|
No fever | Fever | OR (p-value) | OR (p-value) | |
Season | ||||
Wet season | 69.9% (613/877) | 30.1 (264/877) | Reference | reference |
Dry season | 88.8% (790/890) | 11.2 (100/890) | 0.29 (<0.001) | 0.31 (<0.001) |
Age groups* | ||||
0–4 years | 77.7% (240/309) | 23.3% (69/309) | Reference | Reference |
5–14 years | 73.1% (457/625) | 26.9% (168/625) | 1.28 (0.13) | 1.39 (0.06) |
15–24 years | 79.5% (186/234) | 20.5% (48/234) | 0.90 (0.61) | 0.98 (0.94) |
25–45 years | 82.9% (295/356) | 17.1% (61/356) | 0.72 (0.09) | 0.88 (0.53) |
> 45 years | 92.5% (221/239) | 7.5% (18/239) | 0.28 (<0.001) | 0.31 (<0.001) |
Parasite prevalence | ||||
Slide positive [%] (total number) | 73.7 (558/757) | 26.3 (199/757) | 1.83 (<0.001) | |
Parasite density** | ||||
no parasites | 60.6% (849/1401) | 45.2% (164/363) | Reference | Reference |
1–500 parasites/μl | 22.9% (321/1401) | 24.8% (90/363) | 1.45 (0.01) | 1.00 (0.96) |
501–1000 parasites/μl | 5.9% (83/1401) | 7.4% (27/363) | 1.68 (0.028) | 1.03 (0.90) |
1001–2500 parasites/μl | 4.6% (64/1401) | 7.2% (26/363) | 2.10 (0.003) | 1.08 (0.77) |
2501–5000 parasites/μl | 2.9% (40/1401) | 4.4% (16/363) | 2.07 (0.018) | 0.97 (0.92) |
5001–10 000 parasites/μl | 1.9% (26/1401) | 5.0% (18/363) | 3.58 (<0.001) | 1.69 (0.12) |
> 10 000 parasites/μl | 1.3% (18/1401) | 6.2% (22/363) | 6.33 (<0.001) | 3.08 (0.001) |
cough | 77.3% (136/176) | 22.7 (40/176) | 1.15 (0.462) | 0.96 (0.85) |