Background
Methods
Study sites
Measurement of habitat productivity and stability
Mosquito species identification
Meteorological data
Data analysis
Results
Habitat characteristics and presence of mosquito larvae
Characteristics | Categories | Anopheles present no/Total No. (%) | p-value |
---|---|---|---|
Study site | Anyakpor | 112/343 (32.7) | p = 0.000 χ2 = 22.3392 |
Dodowa | 56/92(60.8) | ||
Habitat type | Man-made pond | 31/145 (21.4) | p = 0.000 χ2 = 36.5267 |
Well | 87/214 (40.4) | ||
Swamp | 10/21 (47.6) | ||
Puddle | 33/43 (76.7) | ||
Furrow | 7/12 (58.3) | ||
Total | 168/435 (38.6) | ||
Land-use type | Farmland | 119/363 (32.8) | p = 0.000 χ2 = 24.3645 |
Road | 24/40 (60.0) | ||
Compound/Home | 9/9 (100) | ||
Water body | 16/23 (66.7) | ||
Presence of culicines | Absent | 112/308 (36.4) | p = 0.132 χ2 = 2.2671 |
Present | 196/308 (63.6) | ||
Habitat size categorized | < 10 m | 133/323 (41.2) | p = 0.033 χ2 = 6.8114 |
10–100 m | 31/106 (29.3) | ||
> 100 m | 4/6 (66.7) | ||
Vegetation cover categorized | None | 54/123 (43.9) | p = 0.001 χ2 = 19.9549 |
< 24% | 44/83 (53.0) | ||
25–49% | 19/46 (41.3) | ||
50–74% | 21/59 (35.6) | ||
75–100% | 30/124 (23.2) | ||
Presence of algae | Absent | 106/284 (37.3) | p = 0.446 χ2 = 0.5804 |
Present | 178/284 (62.7) | ||
Surface debris | Absent | 43/126 (34.1) | p = 0.219 χ2 = 1.5110 |
Present | 83/126 (65.9) | ||
Emergent plant | Absent | 107/252 (42.5) | p = 0.014 |
Present | 145/252 (57.5) | χ2 = 3.7254 |
Anopheles presence | aOR | St. Err | t-value | p-value | [95% Conf. Interval] | Sig. |
---|---|---|---|---|---|---|
Habitat type | ||||||
Man-made pond | ||||||
Well | 2.085 | 0.738 | 2.08 | 0.038 | 1.042–4.173 | ** |
Swamp | 2.017 | 1.225 | 1.16 | 0.248 | 0.614–6.631 | |
Puddle | 2.248 | 1.500 | 1.21 | 0.225 | 0.608–8.311 | |
Furrow | 1.212 | 0.926 | 0.25 | 0.801 | 0.271–5.420 | |
Site | ||||||
Dodowa | 1.000 | |||||
Anyakpor | 0.561 | 0.424 | − 0.77 | 0.444 | 0.128–2.463 | ** |
Land-use type | ||||||
Farmland | 1.000 | |||||
Road | 1.031 | 0.818 | 0.04 | 0.969 | 0.218–4.884 | |
Compound/home | 1.000 | |||||
Water body | 3.414 | 2.957 | 1.42 | 0.156 | 0.625–18.641 | |
Habitat size | ||||||
< 10 m | 1.000 | |||||
10–100 m | 0.492 | 0.201 | − 1.73 | 0.083 | 0.220–1.097 | * |
> 100 m | 0.973 | 1.052 | − 0.03 | 0.980 | 0.117–8.096 | |
Vegetation cover | ||||||
None | 1.000 | |||||
< 24% | 1.331 | 0.412 | 0.93 | 0.355 | 0.726–2.440 | |
25–49 | 0.780 | 0.328 | − 0.59 | 0.554 | 0.342–1.778 | |
50–74 | 0.554 | 0.222 | − 1.47 | 0.141 | 0.253–1.215 | |
75–100 | 0.208 | 0.077 | − 4.24 | 0.001 | 0.101–0.430 | *** |
Culex presence | ||||||
Absent | 1.000 | |||||
Present | 1.669 | 0.480 | 1.78 | 0.075 | 0.950–2.933 | * |
Algae | ||||||
Absent | 1.000 | |||||
Present | 1.202 | 0.385 | 0.57 | 0.565 | 0.642–2.253 | |
Surface debris | ||||||
Absent | 1.000 | |||||
Present | 0.609 | 0.174 | − 1.73 | 0.083 | 0.348–1.068 | * |
Emergent plants | ||||||
Absent | 1.000 | |||||
Present | 0.885 | 0.282 | − 0.38 | 0.702 | 0.474–1.652 | |
Distance to nearest settlement (m) | ||||||
201–250 | 1.000 | |||||
151–200 | 0.345 | 0.158 | − 2.33 | 0.020 | 0.141–0.844 | ** |
101–150 | 0.779 | 0.400 | − 0.49 | 0.626 | 0.285–2.129 | |
51–100 | 1.762 | 2.311 | 0.43 | 0.666 | 0.135–23.039 | |
0–50 | 1.000 |
Mosquito vector larval presence and species composition at the study sites
Mosquito larvae | Number (%) | Total | |
---|---|---|---|
Anyakpor | Dodowa | ||
An. gambiae s.l | 2,534 | 545 | 3079 |
An. pharoensis | 0 | 2 | 2 |
An. rufipes | 0 | 14 | 14 |
Culex | 8,869 | 1717 | 10,586 |
Total | 11,403 | 2278 | 13,681 |
Anopheles gambiae s.l | Anyakpor | Dodowa | Total (%) |
---|---|---|---|
An. gambiae s.s | 70 (19.9%) | 56 (32.6%) | 126 (23) |
An. coluzzii | 284 (70.7%) | 115 (66.9%) | 399 (71) |
An. melas | 31 (8.8%) | 0 | 31 (6) |
Unidentified An. gambiae species | 2 (0.6%) | 1(0.5%) | 3 (0.5) |
Total | 387 | 172 | 559 |
Effect of rainfall on habitat stability and Anopheles larval densities
Parameters (mean ± SE) | Rainy season | Dry season | ||
---|---|---|---|---|
Dodowa | Anyakpor | Dodowa | Anyakpor | |
Mean duration that habitats remained aquatic | 7.47 ± 2.5 | 10.68 ± 1.9 | 2.94 ± 3.5 | 8.439 ± 3.8 |
Mean number of times that habitats dried up | 4.00 ± 1.7 | 1.14 ± 0.7 | 6.21 ± 1.7 | 3.92 ± 1.8 |
Mean daily percentage that habitats were aquatic | 95.02 ± 24.6 | 80.30 ± 29.8 | 60.40 ± 24.6 | 55.0 ± 33.3 |
The effect of physicochemical parameters on Anopheles larval presence
Study site | Habitat type | No. of habitats | Temp. (°C) | pH | TDS (ppm) | Cond. (µs) | Salinity (ppm) |
---|---|---|---|---|---|---|---|
Mean ± SD | Mean ± SD | Mean ± SD | Mean ± SD | Mean ± SD | |||
Anyakpor | Swamps | 3 | 33.44 ± 1.16 | 7.05 ± 0.08 | 7.23 ± 1.69 | 10.4 ± 2.50 | 5.21 ± 1.26 |
Artificial ponds | 12 | 32. 35 ± 1.13 | 7.10 ± 0.22 | 5.88 ± 2.05 | 8.62 ± 3.11 | 4.34 ± 1.67 | |
Wells | 24 | 30. 58 ± 1.21 | 7.13 ± 0.11 | 2.75 ± 0.29 | 3.82 ± 0.51 | 1.89 ± 0.26 | |
Furrows | 2 | 33.83 ± 0.67 | 7.02 ± 0.02 | 7.43 ± 1.73 | 11.25 ± 1.97 | 5.56 ± 2.01 | |
Dodowa | Swamps | 3 | 31.14 ± 1.62 | 7.68 ± 0.33 | 2.33 ± 0.85 | 3.23 ± 1.16 | 0.155 ± 0.05 |
Artificial ponds | 6 | 32.09 ± 2 .27 | 7.44 ± 0.24 | 3.55 ± 1.65 | 5.05 ± 2.38 | 0.24 ± 0.12 | |
Puddles | 7 | 31.81 ± 1.83 | 7.60 ± 0.35 | 2.81 ± 1.67 | 3.71 ± 2.04 | 0.19 ± 0.01 | |
Furrows | 2 | 31.20 ± 2.37 | 7.49 ± 0.05 | 1.87 ± 0.23 | 2.64 ± 0.32 | 0.13 ± 0.01 |