Volume 8, Number 12—December 2002
Research
Meteorologic Influences on Plasmodium falciparum Malaria in the Highland Tea Estates of Kericho, Western Kenya
Table
Variable | p | ADFc | β | t | p valuec | τα | Q | Sig. Q |
---|---|---|---|---|---|---|---|---|
Malaria incidence | 5 | -4.00 | 0.0238 | 2.49 | 0.0133 | 0.1801 | 58.7394 | 0.0097 |
Total admissions | 6 | -2.76 | -0.0069 | -0.28 | 0.7820 | -0.4151 | 30.9302 | 0.7083 |
Tmean met. stat. (oC) | 8 | -3.41 | 0.0004 | 1.76 | 0.0799 | -0.0211 | 40.8630 | 0.2653 |
Rain met. stat. (mm) | 1 | -11.91 | -0.0202 | -0.52 | 0.6066 | -0.0074 | 43.3753 | 0.1858 |
Tmean clim. (oC) | 1 | -7.51 | 0.0035 | 1.60 | 0.1103 | -0.0980 | 46.6888 | 0.1094 |
Tmax clim. (oC) | 24 | -4.66 | 0.0070 | 1.68 | 0.0935 | 0.0592 | 22.6634 | 0.9592 |
Tmin clim. (oC) | 1 | -8.36 | 0.0038 | 1.55 | 0.1233 | -0.1944 | 45.1424 | 0.1412 |
Precipitation clim. (mm) | 1 | -11.70 | -0.0098 | -0.36 | 0.7205 | -0.0745 | 34.2984 | 0.5497 |
Vapor pressure clim. (hPa) | 1 | -8.37 | 0.0038 | 1.66 | 0.0974 | -0.1829 | 45.5674 | 0.1318 |
Garnham suitability (mo)d | 4 | -4.21 | -0.0380 | -0.89 | 0.3850 | -0.4488 | 5.6658 | 0.7729 |
aTmean, the mean monthly temperature; Tmax, the mean of maximum monthly temperatures; Tmin, the mean of minimum monthly temperatures; met. stat., meteorologic station data from the Kericho tea estate; clim., data derived from the global gridded climatology dataset (33,34).
bFigures in bold denote significance at the 5% level. p is the number of lagged differenced dependent variables selected.
cADF, the Augmented Dicke-Fuller t-test for γ=0. The 5% critical value is -3.45. Exact p values are not available for ADF and τα statistics. The distribution of the t statistic for the slope parameter β has the standard t distribution under the assumption that γ<0. τα is the t statistic for the intercept term in the autoregression without a linear time trend. This test is the appropriate one for a trend if γ=0. Its 5% critical value is 2.54. The Q statistic is a portmanteau test for general serial correlation and is distributed as chi square (39).
dGarnham suitability (1,4) refers to the number of months with a mean monthly temperature exceeding 15°C and monthly rainfall totals exceeding 152 mm (when the gridded climatology data are used). These data are therefore annual data, whereas all other time-series are monthly observations.
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