Health Risk Assessment of PM10 Exposure among School Children and the Proposed API Level for Closing the School during Haze in Malaysia

Introduction: During haze, at what level should Air Pollutant Index (API) showed, public or private school be closed is not without controversy and is very much debated. Therefore, the aim of this paper is to objectively quantify the potential inhaled dose of PM10 associated with exposure at school and home microenvironments during haze. The result of the health risk assessment will be used to propose the API level for closing the school during haze episode. Methods: A hypothetical haze exposure scenario was created using the breakpoints of PM10 concentration for calculation of API and respective inhaled dose during haze. To determine the potential inhaled dose, we have considered many factors that include time spent for specific physical intensity at school and home microenvironments, age-specific and physical intensity-specific inhalation rate (m3/min), and the indoor/outdoor ratio of PM10. To calculate risk quotient (RQ), the inhaled dose was compared with the health reference dose computed based on the concentration of PM10 in the Malaysian Ambient Air Quality Standard. Results: When considering the specific exposure at each microenvironment (school and home), the potential inhaled dose of PM10 was substantially lower when school is closed for both primary and secondary school. The calculated risk quotient (RQ) indicates that primary school children are likely to be affected at slightly lower PM10 concentration (equivalent to API of 197) as compared to secondary school children. Short duration of high physical activity intensity during school breaks has contributed to a large proportion of inhaled dose among school children indicating the important to avoid physical activities during haze. Conclusion: Based on the assessment, taking into account the uncertainty of risk assessment methodology, we proposed school to be closed when API reach 190 for both primary and secondary schools. These findings and recommendations are only valid for naturally ventilated school and applicable in the context of the current API calculation system and the existing Recommended Air Quality Guideline values in Malaysia

Tabiat pengambilan ulam-ulaman di kalangan orang dewasa pelbagai etnik di Selangor

Satu soal selidik telah dijalankan bertujuan untuk menilai tahap pengambilan ulam-ulaman di Negeri Selangor di kalangan 252 orang dewasa (> 17 tahun) (lelaki 28.6%, wanita 71.4%), pelbagai etnik (Melayu-51.6%; Cina-30.5%; India-17.5%) dengan umur purata 42.7 ± 13.9 tahun. Pengumpulan data pengambilan ulam-ulaman dibuat menggunakan kaedah sampel pendua 24 jam dan disertakan dengan soal selidik persepsi. Keputusan kajian ini mendapati bahawa ulam segar digemari oleh hampir semua subjek (82.1%) terutama daripada kalangan etnik Melayu (92.3%). Sebanyak 52% subjek memilih ulam celur/rebus. Faktor utama pengambilan ulam-ulaman adalah kerana khasiat yang baik kepada kesihatan serta rasanya yang enak dan unik. Ulam segar utama yang diambil oleh subjek kajian adalah mentimun (Cucumis sativus) (60.6%), kacang botol (Psophocarpus tetragonolobus) (33%), pegaga (Hydrocotyle asiatica) (31.5%), daun salad (Lactuca sativa) (27.6%), petai (Parkia speciosa) (29%) dan ulam raja (Cosmos caudatus) (21.9%). Sementara ulam celur/rebus pilihan adalah pucuk ubi (Manihot esculenta) (31.5%), bendi (Hibiscus esculentus) (12.5%) dan jantung pisang (Musa sapientum) (20.1%). Tiada perbezaan bererti (P > 0.05) terhadap pengambilan ulam-ulaman di kalangan etnik berbeza di mana nilai median untuk jumlah pengambilan sehari adalah pada julat 30-39 g/hari. Ulam berpotensi menjadi sumber dalam meningkatkan pengambilan sayursayuran bagi memenuhi saranan oleh Badan Kesihatan Sedunia (WHO) iaitu 400 g sehari

Sylvatic dengue virus type 4 in Aedes aegypti and Aedes albopictus mosquitoes in an urban setting in Peninsular Malaysia.

Dengue fever is endemic in Malaysia, contributing to significant economic and health burden in the country. Aedes aegypti and Ae. albopictus are the main vectors of the dengue virus (DENV), which circulates in sylvatic and human transmission cycles and has been present in Malaysia for decades. The study investigated the presence and distribution of DENV in urban localities in the Klang Valley, Peninsular Malaysia. A total of 364 Ae. aegypti and 1,025 Ae. albopictus larvae, and 10 Ae. aegypti and 42 Ae. albopictus adult mosquitoes were screened for the presence of DENV. In total, 31 (2.2%) samples were positive, of which 2 Ae. albopictus larvae were co-infected with two serotypes, one with DENV-2 and DENV-3 and the other with DENV-3 and DENV-4. Phylogenetic analysis determined that the isolates belonged to DENV-1 genotype I (1 Ae. aegypti adult), DENV-2 (1 Ae. albopictus larva), DENV-3 genotype V (3 Ae. aegypti larvae and 10 Ae. albopictus larvae) and DENV-4 genotype IV (6 Ae. aegypti larvae and 12 Ae. albopictus larvae), a sylvatic strain of DENV-4 which was most closely related with sylvatic strains isolated from arboreal mosquitoes and sentinel monkeys in Peninsular Malaysia in the 1970s. All four DENV serotypes were co-circulating throughout the study period. The detection of a sylvatic strain of DENV-4 in Ae. aegypti and Ae. albopictus mosquitoes in urban areas in Peninsular Malaysia highlights the susceptibility of these vectors to infection with sylvatic DENV. The infectivity and vector competence of these urban mosquitoes to this strain of the virus needs further investigation, as well as the possibility of the emergence of sylvatic virus into the human transmission cycle

The Effects of Meteorological Factors on Dengue Cases in Malaysia

Dengue is a vector-borne disease affected by meteorological factors and is commonly recorded from ground stations. Data from ground station have limited spatial representation and accuracy, which can be overcome using satellite-based Earth Observation (EO) recordings instead. EO-based meteorological recordings can help to provide a better understanding of the correlations between meteorological variables and dengue cases. This paper aimed to first validate the satellite-based (EO) data of temperature, wind speed, and rainfall using ground station data. Subsequently, we aimed to determine if the spatially matched EO data correlated with dengue fever cases from 2011 to 2019 in Malaysia. EO data were spatially matched with the data from four ground stations located at states and districts in the central (Selangor, Petaling) and east coast (Kelantan, Kota Baharu) geographical regions of Peninsular Malaysia. Spearman’s rank-order correlation coefficient (ρ) was performed to examine the correlation between EO and ground station data. A cross-correlation analysis with an eight-week lag period was performed to examine the magnitude of correlation between EO data and dengue case across the three time periods (2011–2019, 2015–2019, 2011–2014). The highest correlation between the ground-based stations and corresponding EO data were reported for temperature (mean ρ = 0.779), followed by rainfall (mean ρ = 0.687) and wind speed (mean ρ = 0.639). Overall, positive correlations were observed between weekly dengue cases and rainfall for Selangor and Petaling across all time periods with significant correlations being observed for the period from 2011 to 2019 and 2015 to 2019. In addition, positive significant correlations were also observed between weekly dengue cases and temperature for Kelantan and Kota Baharu across all time periods, while negative significant correlations between weekly dengue cases and temperature were observed in Selangor and Petaling across all time periods. Overall negative correlations were observed between weekly dengue cases and wind speed in all areas from 2011 to 2019 and 2015 to 2019, with significant correlations being observed for the period from 2015 to 2019. EO-derived meteorological variables explained 48.2% of the variation in dengue cases in Selangor. Moderate to strong correlations were observed between meteorological variables recorded from EO data derived from satellites and ground stations, thereby justifying the use of EO data as a viable alternative to ground stations for recording meteorological variables. Both rainfall and temperature were found to be positively correlated with weekly dengue cases; however, wind speed was negatively correlated with dengue cases

Achieving high uptake of human papillomavirus vaccination in Malaysia through school-based vaccination programme

Abstract Background In 2006, 4 years of planning was started by the Ministry of Health, Malaysia (MOH), to implement the HPV (human papillomavirus) vaccination programme. An inter-agency and multi-sectoral collaborations were developed for Malaysia’s HPV school-based immunisation programme. It was approved for nationwide school base implementation for 13-year-old girls or first year secondary students in 2010. This paper examines how the various strategies used in the implementation over the last 7 years (2010–2016) that unique to Malaysia were successful in achieving optimal coverage of the target population. Methods Free vaccination was offered to school girls in secondary school (year seven) in Malaysia, which is usually at the age of 13 in the index year. All recipients of the HPV vaccine were identified through school enrolments obtained from education departments from each district in Malaysia. A total of 242,638 girls aged between 12 to 13 years studying in year seven were approached during the launch of the program in 2010. Approximately 230,000 girls in secondary schools were offered HPV vaccine per year by 646 school health teams throughout the country from 2010 to 2016. Results Parental consent for their daughters to receive HPV vaccination at school was very high at 96–98% per year of the programme. Of those who provided consent, over 99% received the first dose each year and 98–99% completed the course per year. Estimated population coverage for the full vaccine course, considering also those not in school, is estimated at 83 to 91% per year. Rates of adverse events reports following HPV vaccination were low at around 2 per 100,000 and the majority was injection site reactions. Conclusion A multisectoral and integrated collaborative structure and process ensured that the Malaysia school-based HPV immunisation programme was successful and sustained through the programme design, planning, implementation and monitoring and evaluation. This is a critical factor contributing to the success and sustainability of the school-based HPV immunisation programme with very high coverage

Fish consumption pattern among adults of different ethnics in Peninsular Malaysia

Background: Understanding different patterns of fish consumption is an important component for risk assessment of contaminants in fish. A few studies on food consumption had been conducted in Malaysia, but none of them focused specifically on fish consumption. The objectives of this study were to document the meal pattern among three major ethnics in Malaysia with respect to fish/seafood consumption, identify most frequently consumed fish and cooking method, and examine the influence of demographic factors on pattern of fish consumption among study subjects. Methods: A cross-sectional survey was conducted between February 2008 and May 2009 to investigate patterns of fish consumption among Malaysian adults in Peninsular Malaysia. Adults aged 18 years and above were randomly selected and fish consumption data were collected using a 3-day prospective food diary. Results: A total of 2,675 subjects, comprising male (44.2%) and female (55.7%) participants from major ethnics (Malays, 76.9%; Chinese, 14.7%; Indians, 8.3%) with a mean age of 43.4±16.2 years, were involved in this study. The results revealed 10 most frequently consumed marine fish in descending order: Indian mackerel, anchovy, yellowtail and yellow-stripe scads, tuna, sardines, torpedo scad, Indian and short-fin scads, pomfret, red snapper, and king mackerel. Prawn and squid were also among the most preferred seafood by study subjects. The most frequently consumed freshwater fish were freshwater catfish and snakehead. The most preferred cooking style by Malaysians was deep-fried fish, followed by fish cooked in thick and/or thin chili gravy, fish curry, and fish cooked with coconut milk mixed with other spices and flavorings. Overall, Malaysians consumed 168 g/day fish, with Malay ethnics’ (175±143 g/day) consumption of fish significantly (p<0.001) higher compared with the other two ethnic groups (Chinese=152±133 g/day, Indians=136±141 g/day). Conclusion: Fish consumption was significantly associated with ethnicity, age, marital status, residential area, and years of education of adults in Peninsular Malaysia, and the data collected are beneficial for the purpose of health risk assessment on the intake of contaminants through fish/seafood consumption