Assessment of Daytime and Nighttime Ground Level Ozone Pollution in Malaysian Urban Areas

@#Introduction: Ozone (O3 ) is a significant component of photochemical smog as a typical secondary which is formed via nitrogen oxide photochemical interactions with volatile organic compounds (VOCs). This research discerns the complex influence of meteorological parameters and air pollutants influencing O3 concentrations. Methods: Data were acquired from 1 January 2018 until 31 December 2020 that including ozone (O3 ), nitrogen oxide (NOx), nitric oxide (NO), sulphur dioxide (SO2 ), nitrogen dioxide (NO2 ), carbon monoxide (CO), particulate matter (PM10, PM2.5), wind speed, solar radiation, temperature, and relative humidity (RH). Data were analysed using descriptive statistics in terms of line graphs. Results: The results demonstrate that the O3 concentration peaked around 14:00 hours and dropped at night (20:00 hours) owing to the lack of sunshine and redox processes. Conclusion: In conclusion, ozone precursors played an important role in ozone formation and the findings of this research are valuable for policymakers and other interested parties

Profiling of Aedes Mosquito Breeding Sites at Residential Construction Sites in Malaysia

@#Introduction: Poor waste management led to mosquito breeding grounds. Previous research found that construction sites are the mosquito breeding area thus it’s important to understand how construction sites affect mosquito breeding. Methods: This study utilized a prospective study to determine the characteristic of breeding preference in residential construction sites. On-field breeding preference survey was conduct in the selected project site in 12 weeks (1st October 2021 until 31st December 2021). Wet container inspection was carried out according to types of the residential construction building and progress of the site. All possible wet materials and containers was inspected and record accordingly in the form during the surveillance. Results: Result shows that the most preferred containers found was building floor (41.68%), others such as planter box that use for landscape purpose, drainage system, building mould and lift wells. The results of the research indicate that prospective containers with water and breeding sites at high rise construction sites were found to be more than those at low rise construction sites. Conclusion: Overall, substantially fewer water containers were discovered in low rise projects compared to high rise projects. Construction management need encourage all the workers to do best management practice such as proper waste disposal and removal of the water and possible wet container and conduct awareness among the workers.

Spatial and Temporal Distributions Pattern of Dengue Fever Cases: A Ten Years Trends in Kuantan, Pahang

@#Introduction: Dengue fever (DF) is a prominent vector-borne disease spread by mosquitos of the Aedes genus (mainly Aedes aegypti, and even Aedes albopictus), a tropical regions vector. The purpose of this research was to establish the spatial and temporal distribution patterns of DF cases in the study area between 2010 and 2020. Methods: The correlation between the Kuantan sub-district and dengue haemorrhagic fever (DHF) incidence is examined in this study using spatial analysis. The correlation was calculated using spatial autocorrelation, Moran’s Index (Moran’s I) and Spatial Autocorrelation of Local Indicators (LISA). Moran’s index is a worldwide indicator used to determine whether or not disease transmission has geographical autocorrelation in disease transmission. Results: The results indicated that between 2011 and 2020, the monthly Moran’s I of dengue transmission in Kuantan was estimated to range between -0.685 and 0.338. The lowest reading of Moran’s index was -0.685 in May 2015, whereas the highest reading was 0.338 in May 2019. This reflects the strong spatial autocorrelation of dengue transmission in Kuantan over the last decade. The LISA analysis revealed significant spatial autocorrelations on DF cases in Kuantan for three (3) out of six (6) sub-districts (50%) with a significance level of 2%. This suggests that there are spatial autocorrelations in Kuala Kuantan, Beserah and Penor sub-district that influence the distribution of DHF transmission. Conclusion: The results reveal that the spatial autocorrelation analysis method can be a tool for relevant researchers to understand the pattern of DF transmission study and establish the direction for further study.

A Comparison of Demographic Parameters of Aedes albopictus (Skuse) (Diptera: Culicidae) in Dengue Risk Area at Shah Alam, Selangor

@#Introduction: Aedes albopictus is known for its aggressiveness towards human and recently expanded to more countries outside the native regions. Thus, the demographic parameters of Aedes albopictus are important to determine the characteristics of this species mosquitoes in terms of the reproduction rates and dispersal distance. Materials and Methods: This study, was performed using a Shah Alam strain of Aedes albopictus originally collected in twenty district areas of the central zone of Shah Alam. This research applies field work-study with a cross-sectional design to investigate the demographic parameters of Aedes albopictus. The demographic evaluation of Aedes albopictus was conducted under the control environment in insectarium. Results: Investigation on the demographic parameters of Aedes albopictus clearly showed that there is a significance different observed in the total number of mosquito eggs produced in both high and low incidence rate IR areas (p=0.03). In contrast, other parameters showed insignificant value between high and low IR areas. Conclusion: The key to control the mosquito vectors population is by tracking the vector’s life cycle including its survival. Therefore, the outcome of this study may provide as a baseline to estimate the dengue outbreak in the current episystem.

Spatial-Temporal Pattern of Mosquito-Borne Disease Occurrence Based on Epidemiological Data: A Case Study from Terengganu

@#Introduction: The trend of several mosquito-borne diseases in Malaysia has shown an increasing pattern over the past few years despite close monitoring and continuous control initiatives by public health authority. The objective of this study is to determine the spatial and temporal epidemiology of mosquito-borne disease in Terengganu from the year 2009 to 2018. Terengganu has been selected because it is geographically unique and experiences two monsoon seasons per year. Methods: Weekly surveillance data of mosquito-borne diseases which include dengue fever, malaria, filariasis, Japanese Encephalitis (JE) and chikungunya from 2009 to 2018 were collected from the Terengganu State Health Department. The variables included in the dataset mainly comprises of disease onset, diagnosis, case category, area (district) and site of onset. The data has been monitored spatial and temporal in which to explore the distribution pattern of the disease. The annual average for each type of mosquito-borne disease was determined using time-series and is further analysed by using geographical information system (GIS) tools to form spatial statistical analysis. Results: Results indicate that the temporal distribution of the mosquito-borne disease in Terengganu increases slightly despite a fluctuating pattern from the year 2009 to 2018 and there are between each type of mosquito-borne disease. Spatial analysis showed different stratification between seasons as well as the areas that are more susceptible to each disease. Conclusion: The results obtained in this present study through spatial and temporal analysis revealed that mosquito-borne diseases show a dynamic pattern in distribution. It can be concluded that the occurrence of the diseases depends on the geographical area and the weather within the region. This study provides public health authorities with a comprehensive assessment that will be useful for surveillance and monitoring, as well as for predicting and managing mosquito-borne disease outbreaks effectively

Temperature Stress Effect on the Survival of Aedes albopictus (Skuse) (Diptera: Culicidae) Adult Mosquito: An Experimental Study

Abstract@#Introduction: The survivorship of mosquito is the most important aspect that affects its ability as a pathogen transmitting vector such as Aedes albopictus which is a vector of dengue. In this study, temperature stress effect on the survival of adult Aedes albopictus were investigated. Methods: It was conducted by manipulating different constant temperatures (15°C to 35°C) on juvenile stage of Ae. albopictus in natural and artificial container. Then, the development growth of adult mosquito was observed under laboratory condition. The effects of exposed temperature on certain biological parameters of adult mosquito were evaluated in terms of survival rates, longevity of female mosquito, fecundity rate, gonotrophic cycle and wing length of the adult mosquito. Results: In higher temperatures, the longevity of adult female was reduced and the highest longevity was found at optimum temperature (25°C) with average of 8.6 ± 0.18 days and 6.7 ± 0.29 days in natural and artificial container respectively. Both sexes showed a clearly tendency towards decreasing survivorship with increasing temperature where the highest survival was found at 15°C. Conversely, survival was lowest at a high temperature (30°C to 35°C). This study also showed that the wing length of both sexes was significantly affected by the rearing temperature where the longest found at 15°C and the shortest at 35°C. Conclusion: Thus, this study provide useful information of mosquito ecology in response to variation of temperatures.

Study on the Distribution and Abundance of Aedes aegypti and Aedes albopictus in Different Environment Settings for HighRise Buildings

Abstract@#Introduction: Vector surveillance in high-rise buildings is important to predict and monitor the presence of vectors regarding their abundance and distribution. In this study, the infestation profile of Aedes aegypti and Aedes albopictus species in different environmental settings were investigated. Methods: Four high-rise apartments in four different localities were selected for ovitrap surveillance. Fifty ovitraps were placed in semi indoor and outdoor settings. Results: A total of 507 (42.8%) from ovitraps showed the presence of the Aedes species larvae. Out of these, 170 (33.5%) of the positive ovitraps were those placed in semi indoor and 337 (66.5%) in outdoor. Of the total 16,613 Aedes larvae found, 4,130 (24.9%) were from semi indoor, and 12,483 (75.1%) from outdoor. In terms of distribution, Ae. albopictus was predominantly found in outdoor environments (POI=87.5%; MLT=36.45 larvae). Ae. aegypti was also found in outdoor environments (POI=14.89%; MLT=8.26 larvae). There was a significant difference in POI for both Ae. aegypti and Ae. albopictus in the two different environments but no significant difference was observed in MLT, indicating that the density of the Aedes species in both environments was well distributed. Conclusion: In this study, the patterns of Aedes habitat in high-rise apartments were observed. This study has shown an invasion and adaptation of Aedes mosquitoes into the ecosystems of high-rise buildings. It can be concluded that housing designs and the condition of the surrounding environment affects the infestation profile and the distribution of Aedes mosquitoes.

Effects of Artificial Lights on the Biology of Adult Aedes aegypti (Diptera: Culicidae) Mosquitoes

Abstract@#Introduction: The purpose of this research is to evaluate the effects of artificial light exposures on the survivals and life traits of adult Aedes aegypti. Methods: This is an experimental research where triplication of each cage filled with a ratio of 20 male : 20 female mosquitoes were exposed under three different light artificial light which are; yellow light, white light and blue light along with three different photoperiod regimes (light:dark) – (14h:10h, 12h:12h and 8h:16h). During this study, life traits data observed were duration of the females to complete a gonotrophic cycle, mean number of days was calculated as well as fecundity rate each cycle was also observed by calculating its number of eggs. Results: In general, gonotrophic cycle of this species is significantly affected by the exposure of the artificial lights where the white light has allowed this species to complete a gonotrophic cycle faster than yellow and blue light with post hoc Tukey’s HSD p = 0.026, however the gonotrophic cycle is found not affected by the different photoperiod regimes. The fecundity of this species is found not to be affected by the artificial light exposure but is affected by the different photoperiod regimes with p = 0.049. Conclusion: In conclusion, artificial light can significantly affect the gonotrophic cycle of Aedes aegypti species while on the other hand, the fecundity of this species is affected by the different photoperiod instead of different artificial light exposure.

Assessment of Synthetic Attractive Toxic Sugar Bait (ATSB) on Aedes albopictus: An Experimental Design

Abstract@#Introduction: An experimental study was conducted to determine the effects of synthetic chemical artificial toxic sugar bait (ATSB) on adult Aedes albopictus population in a controlled environment. The method uses an “attract and kill” concept and makes use of mosquito’s sugar-feeding behaviour. Formulations of ATSB consists of natural scents as an attractant, a sugar solution as a feeding stimulant and an oral toxin such as boric acid to eliminate mosquito population. Methods: The experiment was conducted in two phases; (i) the first phase aimed to determine the optimum sucrose concentration (10%, 30%, 50% and 70%) that will elicit the highest biting and fecundity rates in female mosquitoes and (ii) the second phase aimed to identify the ATSB, optimum sucrose from phase one incorporated with boric acid (0.1%,0.5% and 1%), that cause the highest mortality rates of adult female Aedes albopictus in a laboratory environment. Results: Seventy percent sucrose concentration was selected as the optimum sucrose concentration because the ingestion of the solution cause the highest biting and fecundity rates in mosquito compare to other sucrose concentrations. Meanwhile, 1% boric acid resulted in the highest mortality rate within two days of the experiment period. Conclusion: This study has identified the optimum sucrose concentration required to attract adult mosquitoes and highlighted the efficacy of 1% boric acid as an effective mosquito adulticide. The findings highlight the potential of ATSB as a valuable vector control method which could be further developed for future use.