Principal component analysis to explore climatic variability and dengue outbreak in Lahore

Various studies have reported that global warming causes unstable climate and many serious impacts to physical environment and public health. the increasing incidence of dengue is now a priority health issue,becomes a health burden of pakistan. in this study it has been investigated that spatial pattern of environment causes the emergence or increasing rate of dengue fever incidence that affects the population and its health. principal component analysis is performed for the purpose of finding if there is/are any general environmental factor/structure which could be affected in the emergence of dengue fever cases in pakistani climate. the daily dengue fever (df) cases in lahore and five climatic variables precipitation (p),relative humidity (h),maximum temperature (mx),minimum temperature (mn) and wind speed (w) were taken from 2011 to 2012. principal component is applied to find structure in data for dengue period. the pc1 is the linear combination of mx,mn and w and interpreted as windy and hot (htw). pc2 is the combination of h and p and this factor can be named as wetness (wt). the pc3 is found to be contrast between w and p that may label as windy and dry (wd). pc4 is contradiction between h and p that indicate in lahore there is a climatic factor which is humid but no rain (hnr). time series plot of pcs show seasonal variation,graph shape is dominated by weighted average of temperature. correlation analysis shows that dengue fever is highly correlated with maximum and minimum temperatures. pc1 and pc4 of daily climatic factors are positively correlated with daily dengue occurrence and they are highly significant,similarly pc3 of daily is negatively correlated with dengue occurrence. this gives the conclusion that wet and windy weather prevents dengue outbreak.