Analysis of count event data such as mortality cases, were often modelled using Poisson regression model. Maximum likelihood procedures were used by using SAS software to estimate the model parameters of a Poisson regression model. However, the Negative Binomial distribution has been widely suggested as the alternative to the Poisson when there is proof of overdispersion phenomenon. We modelled the mortality cases as the dependent variable using Poisson and Negative Binomial regression and compare both of the models. The procedures were done in SAS by using the function PROC GENMOD. The results showed that the mortality data in Poisson regression exhibit large ratio values between deviance to degree of freedom which indicate model misspecification or overdispersion. This large ratio was found to be reduced in Negative Binomial regression. The Normal probability plot of Pearson residual confirmed that the Negative Binomial regression is a better model than Poisson regression in modelling the mortality data. The objective of this study is to compare the goodness of fit of Poisson regression model and Negative Binomial regression model in the application of air pollution epidemiologic time series study by using SAS software.
This study observed the pattern of reported dengue infections, clinical manifestations, and circulating dengue serotypes in Negeri Sembilan, Malaysia. The aim of this study was to determine the co-circulation of the four different dengue virus serotypes in Negeri Sembilan. We analyzed the surveillance data (VEKPRO) from Negeri Sembilan State Health Department and National Public Health Laboratory, Malaysia on reported dengue infections from 1st January 2010 to 31st December 2010. There were 1466 reported dengue infections, 1342 (91.5%) cases were dengue fever (DF) and 124 (8.5%) were dengue hemorrhagic fever (DHF). The mean age was 32.2± 15.8 years old and most were young adults, aged 15 years old and older. Males (p < 0.05), and those residing in Seremban district (p < 0.05) were more likely to get dengue infections. Symptoms presented upon admission were fever (100%), headache (99.9%), myalgia and arthralgia (98.8%), rash(24.2%), petechiae (16.0%),bleeding tendencies (7.0%) and neurological deficits(1.2%). All four dengue serotypes (DEN 1 – 4) were present, the pre-dominant serotype was DEN-3, noted in January, then existed together with DEN-2 until around May. DEN-1 was the most pre-dominant circulating dengue serotype afterwards, reaching a peak in December 2010. Dengue affected all age groups particularly young adults and males. Most cases reported were in urban areas and Seremban district. Most of the dengue infections occurred in the first half of the year, with the DEN-2 and DEN-3 serotypes being the most predominant.
The study was to determine the concentration of aluminium (Al) and study the physicochemical parameters (pH, total dissolved solids (TDS), turbidity, and residual chlorine) in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S), the treatment plant outlet (TPO), and at the nearest houses (H1) and the furthest houses (H2) from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90). The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU). Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L). Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems.
Dengue is one of the main vector-borne diseases affecting tropical countries and spreading to other countries at the global scenario without cease. The impact of climate variability on vector-borne diseases is well documented. The increasing morbidity, mortality and health costs of dengue and dengue haemorrhagic fever (DHF) are escalating at an alarming rate. Numerous efforts have been taken by the ministry of health and local authorities to prevent and control dengue. However dengue is still one of the main public health threats in Malaysia. This study was carried out from October 2009 by a research group on climate change and vector-borne diseases. The objective of this research project is to assess the community vulnerability to climate variability effect on dengue, and to promote COMBI as the community responses in controlling dengue. This project also aims to identify the community adaptive measures for the control of dengue. Various research methodologies were applied in this research project in different localities. Site visits, review on surveillance data and mapping on Aedes population, dengue cases and climate variability, community survey on the knowledge prevalence , opinions and practices (KOP) and mosquito ecology were carried out during pre- and post intervention phases. Community vulnerability towards Aedes and dengue were mapped out applying GIS. A series of workshops, group discussions and activities such as COMBI activities to promote Aedes control were conducted involving the Ledang communities, the health district officers and UKM researchers. These activities also included interventions and documentation of community responses and their adaptive capacities towards dengue. Trends on Aedes population, dengue cases and community surveys pre and post-interventions, the processes for dengue control activities were analysed. The research findings could provide understanding on the community vulnerability to dengue against climate variability, their responses and adaptive measures. The community advocacy on combats against Aedes is a possible effective solution in dengue control. This research could provide other dimensions in public health management to address the impacts of climate change on vector-borne diseases.