1. Epidemiology and Global Health
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Local human movement patterns and land use impact exposure to zoonotic malaria in Malaysian Borneo

  1. Kimberly M Fornace  Is a corresponding author
  2. Neal Alexander
  3. Tommy R Abidin
  4. Paddy M Brock
  5. Tock H Chua
  6. Indra Vythilingam
  7. Heather M Ferguson
  8. Benny O Manin
  9. Meng L Wong
  10. Sui H Ng
  11. Jon Cox
  12. Chris Drakeley
  1. London School of Hygiene and Tropical Medicine, United Kingdom
  2. Universiti Malaysia Sabah, Malaysia
  3. University of Glasgow, United Kingdom
  4. University of Malaya, Malaysia
Research Article
Cite this article as: eLife 2019;8:e47602 doi: 10.7554/eLife.47602
5 figures, 6 tables and 4 additional files

Figures

Analysis methods used to estimate individual and community-level exposure to P. knowlesi sporozoite positive An. balabacencis bites.
https://doi.org/10.7554/eLife.47602.002
Study sites and sampled houses.

(A) Location of study sites and tracked houses (households with one or more individual GPS tracked) and survey houses (households with only questionnaire data collected and used for prediction) in (B) Matunggong, Kudat and (C) Limbuak, Banggi; description of land cover classification and survey methodology in Fornace et al. (2018).

https://doi.org/10.7554/eLife.47602.003
Human movement relative to habitat.

(A) Example of GPS tracks from a 22-year-old male plantation worker in Matunggong over aerial imagery, (B) Probability density of an individual utilisation distribution calculated from GPS tracks.

https://doi.org/10.7554/eLife.47602.005
Mosquito biting rates.

(A) An. balabacensis biting rate per person-night from data collected in Matunggong, (B) Predicted mean An. balabacensis biting rates per month from spatiotemporal models, (C) Predicted number of bites for all individuals residing in Matunggong by distance from secondary forest, and by (D) Distance from households.

https://doi.org/10.7554/eLife.47602.009
Model outputs relative to land cover.

(A) Land use in Matunggong site, (B) Predicted number of person- nights for entire community per grid cell, (C) Predicted mosquito biting rates, (D) Predicted infected bites per grid cell.

https://doi.org/10.7554/eLife.47602.012

Tables

Table 1
Baseline characteristics of study site communities and sampled populations
https://doi.org/10.7554/eLife.47602.004
MatunggongLimbuak
SampledCommunity*SampledCommunity*
N134958109633
Gender
Male, % (n)51.5% (69)46.1% (442)47.7% (52)46.1% (292)
Women, % (n)48.5% (65)53.9% (516)52.3% (57)53.9% (341)
Age in years, median (IQR)31 (17–53)32.5 (8–51)29 (15–46)30 (15–47)
Main occupation, % (n)
Farming29.9% (40)28.6% (274)7.3% (8)10.2% (65)
Plantation work10.4% (14)8.6% (82)10.1% (11)7.6% (48)
Student26.1% (35)27.7% (265)26.6% (29)21.0% (133)
Other6.7% (9)9.1% (87)15.6% (17)14.4% (91)
No employment/housewife26.9% (36)26.1% (250)40.4% (44)46.8% (296)
  1. *Community includes all individuals eligible for these surveys (residents ages eight and over).

Table 2
Home range estimates by demographic group and site
https://doi.org/10.7554/eLife.47602.006
Area of 99% UD for all movement (hectares)
Median (IQR)
Area of 99% UD from 6pm – 6am (hectares)
Median (IQR)
Demographic group
Men32.09 (7.07, 148.93)4.50 (2.79, 19.53)
Women74.25 (12.24, 320.74)6.08 (2.79, 24.17)
Children (under 15)26.01 (6.39, 151.94)3.83 (2.79, 8.73)
Occupation
Farming29.34 (8.15, 324.38)6.75 (2.79, 19.80)
Plantation work49.14 (9.72, 201.33)4.59 (2.79, 27.72)
Fishing442.49 (40.07, 1189.00)227.16 (4.05, 465.14)
Office work96.80 (63.61, 256.75)13.63 (2.88, 20.14)
Other19.98 (6.30, 26.82)2.97 (2.61, 18.27)
No employment/housewife43.38 (11.97, 157.59)3.60 (2.79, 19.12)
Site
Limbuak99.99 (24.57, 387.54)7.74 (2.88, 58.05)
Matunggong12.02 (3.94, 85.55)2.97 (2.70, 11.77)
Season
Dry (February – July)28.62 (5.45, 252.45)4.19 (2.79, 19.60)
Wet (August – January)54.90 (17.23, 160.99)4.64 (2.79, 19.35)
Table 3
Estimated coefficients for fixed effects of resource utilisation functions (6pm – 6am).
https://doi.org/10.7554/eLife.47602.007
MatunggongLimbuak
MeanSD95% CIMeanSD95% CI
Probability of presence/absence
Intercept3.3830.8393.218, 3.5473.5710.1043.368, 3.775
Distance from own house (km)−0.9540.006−0.966,–0.942−0.5430.003−0.548,–0.539
Distance from forest (km)5.9970.177−5.650, 6.344−1.8450.050−1.944,–1.746
Distance from road (km)−5.5520.057−5.663,–5.441−3.6560.019−3.694,–3.618
Distance from houses (km)−0.5040.030−0.563,–0.4440.1760.0070.162, 0.189
Elevation (100 MSL)−0.7100.025−0.759,–0.662−1.2680.037−1.340,–1.197
Slope (degrees)−0.02440.002−0.028,–0.021−0.0090.001−0.012,–0.006
Utilisation distributions for locations present
Intercept−6.8460.866−8.549,–5.147−5.6761.017−7.673,–3.681
Distance from own house (km)−0.5830.004−0.590,–0.576−0.3080.002−0.311,–0.305
Distance from forest (km)12.0120.19911.621, 12.403−1.7710.049−1.868,–1.675
Distance from road (km)−0.8330.054−0.939,–0.728−1.5320.011−1.554,–1.511
Distance from houses (km)−0.8190.023−0.864,–0.773−0.2390.006−0.249,–0.228
Elevation (100 MSL)0.6640.0270.610, 0.718−0.2970.003−0.303,–0.297
Slope (degrees)−0.0210.002−0.024,–0.018−0.0340.001−0.036,–0.031
Table 4
Model selection statistics for mosquito biting rates
https://doi.org/10.7554/eLife.47602.008
ModelDIC*Marginal likelihoodModel complexity*RMSE*Mean log-score (CPO)
M1No spatial or temporal effect2367.03−1196.614.124.993.61
M2Spatial effect only2292.97−1175.4740.034.424.16
M3Spatial effect + month as fixed effect2282.88−1173.6843.994.243.90
M4Spatial effect + month as random effect2222.89−1155.9150.284.053.61
M5Spatial effect + month as random walk2225.43−1167.7947.554.093.63
Table 5
Posterior rate ratio estimates and 95% Bayesian credible interval (BCI) for model 4 of mosquito biting rates.
https://doi.org/10.7554/eLife.47602.010
Covariate95% BCI Rate Ratio
Mean2.5%97.5%
Population density0.9630.9161.004
EVI3.1851.1858.532
Distance to forest (100 m)0.9260.8710.976
Spatial range (km)3.1200.5146.926
Table 6
Probabilities of infected bites per person per night for sampled individuals in Matunggong by demographic characteristics.
https://doi.org/10.7554/eLife.47602.011
Predicted infectious bites per night (median [IQR])
Demographic group
Men0.00157 (0.000804, 0.00289)
Women0.00219 (0.000864, 0.00307)
Children (under 15)0.00131 (0.000812, 0.00330)
Occupation
Farming0.00180 (0.00101, 0.00362)
Plantation work0.00216 (0.000680, 0.00278)
Student0.00143 (0.000915, 0.00304)
Other0.00225 (0.000852, 0.00302)
No employment/housewife0.00142 (0.000297, 0.00263)

Additional files

Source code 1

R scripts for fitting biased random bridges (with simulated GPS data), spatiotemporal models of mosquito biting rates and semi-continuous resource utilisation models.

https://doi.org/10.7554/eLife.47602.013
Supplementary file 1

Data sources for assessed spatial and environmental covariates.

https://doi.org/10.7554/eLife.47602.014
Supplementary file 2

Data sources of mosquito biting data.

https://doi.org/10.7554/eLife.47602.015
Transparent reporting form
https://doi.org/10.7554/eLife.47602.016

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