Analysis on the influence of climate variability on the occurrence of dengue fever in Los Baños Makiling Microwatershed, Laguna, Philippines

Date

2011

Abstract

The province of Laguna experienced a drastic increase in the number of individuals affected with dengue fever last 2010. Moreover, a five-fold increase in the annual count of recorded dengue cases from 2001 to 2007, as reported by the Provincial Health Office (PHO), served as a warning of the possible health risk that may be faced by the residents of Laguna. This study sought to understand if climate variability in terms of total monthly rainfall, monthly average relative humidity, monthly average minimum temperature and monthly average maximum temperature influenced the occurrence of dengue fever in the Los Baños - Makiling Microwatershed, which encompasses the municipalities of bay, Los Baños and city of Calamba. In addition, this research sought to contribute to science through the mixed quantitative and qualitative methods employed. In this study, the climatic variable from 2001 to 2009, which were obtained from National Agromet Station (NAS-PAGASA), were correlated with the corresponding monthly number of recorded dengue fever cases from PHO using Pearson product moment correlation analysis. Results show that the occurrence of dengue fever is linearly correlated with rainfall, relative humidity and maximum temperature in the three study site. The occurrence of dengue fever in Los Baños is significantly associated with rainfall (0.720*0 in January and with relative humidity (0.845*0 and maximum temperature (-0.796*) in April. On the other hand, the occurrence of dengue fever in Calamba in the months of

71 September and October are associated with rainfall (0.678*) and maximum temperature (-0.679*0, respectively. Also, the dengue fever cases in bay in April and August are correlated with the maximum temperature (-0.804*) and rainfall (0.896**), respectively. The occurrence of dengue fever is directly associated with rainfall for the three sites. The study concludes that as the volume of rainfall increases, so does the number of dengue fever cases. In contrast, the occurrence of dengue fever is inversely associated with the maximum temperature, to a certain threshold. Thus, as temperature increases, the number of dengue fever cases decreases. The three populations were observed to be aware of the possible and potential risk posed by an increasing frequency of dengue fever cases in the midst of variability in climate, based on the conducted household survey, focus group discussion and key informant interviews, thus the adaptation practices in the three populations. The most predominant practice is cleaning (100%) while the two least dominant practices are used of chemicals (64.9%) and lastly, use of biological control (7.8%). In general, it is recommended that the households should rely less on the use of chemicals because of their harmful effect on the environment. Instead, they should rely more on practices that are considered environmentally safe. These recommended practices are proposed to the LGUs and barangay officials to be promoted as part of the strategies that may be implemented in each study site to prevent the occurrence of dengue fever.

Document Type

Master Thesis

Degree

Master of Science in Environmental Science

College

School of Environmental Science and Management (SESAM)

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