Displaying publications 121 - 140 of 193 in total

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  1. Wilder-Smith A, Tissera H, AbuBakar S, Kittayapong P, Logan J, Neumayr A, et al.
    Glob Health Action, 2018;11(1):1549930.
    PMID: 30560735 DOI: 10.1080/16549716.2018.1549930
    BACKGROUND: Dengue fever persists as a major global disease burden, and may increase as a consequence of climate change. Along with other measures, research actions to improve diagnosis, surveillance, prevention, and predictive models are highly relevant. The European Commission funded the DengueTools consortium to lead a major initiative in these areas, and this review synthesises the outputs and findings of this work conducted from 2011 to 2016. Research areas: DengueTools organised its work into three research areas, namely [1] Early warning and surveillance systems; [2] Strategies to prevent dengue in children; and [3] Predictive models for the global spread of dengue. Research area 1 focused on case-studies undertaken in Sri Lanka, including developing laboratory-based sentinel surveillance, evaluating economic impact, identifying drivers of transmission intensity, evaluating outbreak prediction capacity and developing diagnostic capacity. Research area 2 addressed preventing dengue transmission in school children, with case-studies undertaken in Thailand. Insecticide-treated school uniforms represented an intriguing potential approach, with some encouraging results, but which were overshadowed by a lack of persistence of insecticide on the uniforms with repeated washing. Research area 3 evaluated potential global spread of dengue, particularly into dengue-naïve areas such as Europe. The role of international travel, changing boundaries of vectors, developing models of vectorial capacity under different climate change scenarios and strategies for vector control in outbreaks was all evaluated.

    CONCLUDING REMARKS: DengueTools was able to make significant advances in methods for understanding and controlling dengue transmission in a range of settings. These will have implications for public health agendas to counteract dengue, including vaccination programmes.

    OUTLOOK: Towards the end of the DengueTools project, Zika virus emerged as an unexpected epidemic in the central and southern America. Given the similarities between the dengue and Zika viruses, with vectors in common, some of the DengueTools thinking translated readily into the Zika situation.

    Matched MeSH terms: Dengue/epidemiology*
  2. Lam SK
    Emerg Infect Dis, 1998 Apr-Jun;4(2):145-7.
    PMID: 9621184
    Matched MeSH terms: Dengue/epidemiology
  3. Shepard DS, Undurraga EA, Betancourt-Cravioto M, Guzmán MG, Halstead SB, Harris E, et al.
    PLoS Negl Trop Dis, 2014 Nov;8(11):e3306.
    PMID: 25412506 DOI: 10.1371/journal.pntd.0003306
    Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools for diagnosis, vaccination, vector control, and treatment are being developed, these recommended steps should improve objective, systematic measures of dengue burden to strengthen health policy decisions.
    Matched MeSH terms: Dengue/epidemiology*
  4. Dickin SK, Schuster-Wallace CJ, Elliott SJ
    PLoS One, 2013;8(5):e63584.
    PMID: 23667642 DOI: 10.1371/journal.pone.0063584
    The Water-associated Disease Index (WADI) was developed to identify and visualize vulnerability to different water-associated diseases by integrating a range of social and biophysical determinants in map format. In this study vulnerability is used to encompass conditions of exposure, susceptibility, and differential coping capacity to a water-associated health hazard. By assessing these conditions, the tool is designed to provide stakeholders with an integrated and long-term understanding of subnational vulnerabilities to water-associated disease and contribute to intervention strategies to reduce the burden of illness. The objective of this paper is to describe and validate the WADI tool by applying it to dengue. A systemic ecohealth framework that considers links between people, the environment and health was applied to identify secondary datasets, populating the index with components including climate conditions, land cover, education status and water use practices. Data were aggregated to create composite indicators of exposure and of susceptibility in a Geographic Information System (GIS). These indicators were weighted by their contribution to dengue vulnerability, and the output consisted of an overall index visualized in map format. The WADI was validated in this Malaysia case study, demonstrating a significant association with dengue rates at a sub-national level, and illustrating a range of factors that drive vulnerability to the disease within the country. The index output indicated high vulnerability to dengue in urban areas, especially in the capital Kuala Lumpur and surrounding region. However, in other regions, vulnerability to dengue varied throughout the year due to the influence of seasonal climate conditions, such as monsoon patterns. The WADI tool complements early warning models for water-associated disease by providing upstream information for planning prevention and control approaches, which increasingly require a comprehensive and geographically broad understanding of vulnerability for implementation.
    Matched MeSH terms: Dengue/epidemiology*
  5. Rasli R, Cheong YL, Che Ibrahim MK, Farahininajua Fikri SF, Norzali RN, Nazarudin NA, et al.
    PLoS Negl Trop Dis, 2021 Mar;15(3):e0009205.
    PMID: 33755661 DOI: 10.1371/journal.pntd.0009205
    BACKGROUND: In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance.

    METHOD AND RESULTS: The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species.

    CONCLUSION: The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

    Matched MeSH terms: Dengue/epidemiology
  6. Chang SF, Yang CF, Hsu TC, Su CL, Lin CC, Shu PY
    Am J Trop Med Hyg, 2016 Apr;94(4):804-11.
    PMID: 26880779 DOI: 10.4269/ajtmh.15-0534
    We present the results of a laboratory-based surveillance of dengue in Taiwan in 2014. A total of 240 imported dengue cases were identified. The patients had arrived from 16 countries, and Malaysia, Indonesia, the Philippines, and China were the most frequent importing countries. Phylogenetic analyses showed that genotype I of dengue virus type 1 (DENV-1) and the cosmopolitan genotype of DENV-2 were the predominant DENV strains circulating in southeast Asia. The 2014 dengue epidemic was the largest ever to occur in Taiwan since World War II, and there were 15,492 laboratory-confirmed indigenous dengue cases. Phylogenetic analysis showed that the explosive dengue epidemic in southern Taiwan was caused by a DENV-1 strain of genotype I imported from Indonesia. There were several possible causes of this outbreak, including delayed notification of the outbreak, limited staff and resources for control measures, abnormal weather conditions, and a serious gas pipeline explosion in the dengue hot spot areas in Kaohsiung City. However, the results of this surveillance indicated that both active and passive surveillance systems should be strengthened so appropriate public health measures can be taken promptly to prevent large-scale dengue outbreaks.
    Matched MeSH terms: Dengue/epidemiology*
  7. Packierisamy PR, Ng CW, Dahlui M, Inbaraj J, Balan VK, Halasa YA, et al.
    Am J Trop Med Hyg, 2015 Nov;93(5):1020-1027.
    PMID: 26416116 DOI: 10.4269/ajtmh.14-0667
    Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them.
    Matched MeSH terms: Dengue/epidemiology
  8. Arima Y, Edelstein ZR, Han HK, Matsui T
    Western Pac Surveill Response J, 2013 May 14;4(2):47-54.
    PMID: 24015372 DOI: 10.5365/WPSAR.2012.3.4.019
    Dengue is an emerging vectorborne infectious disease that is a major public health concern in the Asia and the Pacific. Official dengue surveillance data for 2011 provided by ministries of health were summarized as part of routine activities of the World Health Organization Regional Office for the Western Pacific. Based on officially reported surveillance data, dengue continued to show sustained activity in the Western Pacific Region. In 2011, Member States reported a total of 244,855 cases of which 839 died for a case fatality rate of 0.34%. More than 1000 cases were reported each from Cambodia, the Federated States of Micronesia, the Lao People's Democratic Republic, Malaysia, the Philippines, the Marshall Islands, Singapore and Viet Nam. Cambodia, the Federated States of Micronesia and the Marshall Islands reported higher activity relative to 2010. There continues to be great variability among the dengue-endemic countries and areas in the Region in the number of cases and serotype distribution. The continued high notification rate and complex dengue epidemiology in the Region highlight the need for information-sharing on a routine and timely basis.
    Matched MeSH terms: Dengue/epidemiology*
  9. Azil AH, Ritchie SA, Williams CR
    Asia Pac J Public Health, 2015 Oct;27(7):705-14.
    PMID: 25186807 DOI: 10.1177/1010539514548760
    This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method.
    Matched MeSH terms: Dengue/epidemiology*
  10. Shekhar KC, Huat OL
    Asia Pac J Public Health, 1992;6(2):15-25.
    PMID: 1308765 DOI: 10.1177/101053959300600203
    Dengue hemorrhagic fever (DHF), though endemic in the sixties, emerged as a major public health problem in Malaysia from 1973 onwards. The incidence rate of DHF which was 10.1 per 100,000 in 1973 has fallen down to 1.9 per 100,000 in 1987 with a mean case fatality rate of 6.4 per 100 persons. The Chinese appear to be more prone to DHF with the highest mean morbidity rate of 5.5 per 100,000 and case fatality rate of 6.1%. The incidence of DHF is higher in the males with a higher case fatality rate in females. Male Chinese appear to be mainly affected. The overall age-specific incidence rate is highest in two age groups, viz. 5-9 years and 10-19 years of age with a mean morbidity rate of 4.9 cases per 100,000. The mean age-specific case fatality rate was highest in the 0-4 years age group. Dengue hemorrhagic fever is predominantly an urban disease in Malaysia with a mean incidence rate of 5.3 cases per 100,000 as opposed to 1.2 cases per 100,000 being reported from rural areas. The mean overall incidence of deaths in the urban area is 0.5 compared to 0.1 per 100,000 for rural areas. There is a marked seasonal correlation between DHF cases and rainfall, with a peak in August. While all four serotypes of dengue viruses are found in Malaysia, Den 2 appears to be isolated with greater frequency during all the epidemics.
    Publication year=1992-1993
    Matched MeSH terms: Dengue/epidemiology*
  11. Shekhar KC, Huat OL
    Asia Pac J Public Health, 1992;6(3):126-33.
    PMID: 1342799 DOI: 10.1177/101053959200600302
    Dengue fever (DF) has been endemic in Malaysia since 1902 and reached epidemic proportions in 1973. The incidence rate of the disease in 1973 was 5.4 cases per 100,000 and reached 10.4 cases per 100,000 in 1987. The Chinese are the main ethnic community affected showing an overall morbidity rate of 9.0 cases per 100,000 followed by Malays 2.9 cases per 100,000 and Indians 2.4 cases per 100,000. The ethnic race ratio between Chinese, Malays and Indians which was 3.7:1:1.3 in 1975 reached 3.7:1:0.9 in 1987. The attack rates were observed to be higher in the males. The mean male:female ratio among Chinese was 1.1:1, while for Malays and Indians it was 1.5:1. The age-specific morbidity rate was highest in the 10- to 19-year age group followed by the 20- to 29-year age group. Epidemics of dengue fever were found to occur seasonally with the appearance of two peaks, viz. one in June and the other in August. Dengue fever, a rural disease before, has established itself as an urban disease.
    Publication year=1992-1993
    Matched MeSH terms: Dengue/epidemiology*
  12. Appanna R, Ponnampalavanar S, Lum Chai See L, Sekaran SD
    PLoS One, 2010;5(9).
    PMID: 20927388 DOI: 10.1371/journal.pone.0013029
    The human leukocyte antigen alleles have been implicated as probable genetic markers in predicting the susceptibility and/or protection to severe manifestations of dengue virus (DENV) infection. In this present study, we aimed to investigate for the first time, the genotype variants of HLA Class 1(-A and -B) of DENV infected patients against healthy individuals in Malaysia.
    Matched MeSH terms: Dengue/epidemiology; Severe Dengue/epidemiology
  13. Ngwe Tun MM, Muthugala R, Nabeshima T, Rajamanthri L, Jayawardana D, Attanayake S, et al.
    J Clin Virol, 2020 04;125:104304.
    PMID: 32145478 DOI: 10.1016/j.jcv.2020.104304
    BACKGROUND: Sri Lanka experienced its largest dengue outbreak in 2017 with more than 185,000 dengue cases including at least 250 fatalities.

    OBJECTIVES: Our study aimed to characterize the clinical, immunological and virological features of confirmed dengue patients in Sri Lanka during the outbreak in 2017 when unusual manifestations of severe dengue were observed.

    STUDY DESIGN: Sera from 295 patients who were admitted to Teaching Hospital Kandy, Kandy, Sri Lanka between March 2017- January 2018 were subjected to NS1 antigen, IgM and IgG ELISAs, virus isolation, conventional and real time RT-PCR and next generation sequencing.

    RESULTS: Primary and secondary infections were detected in 48.5 % and 51.5 % of the study population, respectively. Two hundred twenty five DENV strains were isolated (219 DENV-2, one DENV-3, two DENV-4, two mixed infections of DENV-2 and -3 and one mixed infection of DENV-2 and -4). Unusual and severe manifestations such as encephalitis, encephalopathy, liver failure, kidney failure, myocarditis, Guillain-Barré syndrome and multi-organ failure were noted in 44 dengue patients with 11 deaths. The viraemia levels in patients with primary infection and unusual manifestations were significantly higher compared to those in patients with secondary infection. A new clade of DENV-2 Cosmopolitan genotype strains was observed with the strains closely related to those from China, Malaysia, Indonesia, Singapore and Taiwan.

    CONCLUSIONS: The new clade of DENV-2 cosmopolitan genotype observed in Sri Lanka in 2017 caused an unprecedented, severe dengue outbreak. The emergence of DENV-3 and DENV-4 in the 2017 outbreak might cause future outbreaks in Sri Lanka.

    Matched MeSH terms: Dengue/epidemiology*; Severe Dengue/epidemiology*
  14. Rohani A, Aidil Azahary AR, Malinda M, Zurainee MN, Rozilawati H, Wan Najdah WM, et al.
    J Vector Borne Dis, 2014 Dec;51(4):327-32.
    PMID: 25540966
    BACKGROUND & OBJECTIVESI: Transovarial transmission of dengue virus in the Aedes vectors is now a well-documented phenomenon reported from many parts of the endemic areas in the world, which played an important role in initiating and maintaining the outbreak in human populations. This study investigated the factors affecting breeding habitats and the relationship with transovarial dengue virus in larvae of Aedes aegypti and Ae. albopictus.
    Matched MeSH terms: Dengue/epidemiology*
  15. Dieng H, Hassan RB, Hassan AA, Ghani IA, Abang FB, Satho T, et al.
    Acta Trop, 2015 May;145:68-78.
    PMID: 25617636 DOI: 10.1016/j.actatropica.2015.01.004
    Even with continuous vector control, dengue is still a growing threat to public health in Southeast Asia. Main causes comprise difficulties in identifying productive breeding sites and inappropriate targeted chemical interventions. In this region, rural families keep live birds in backyards and dengue mosquitoes have been reported in containers in the cages. To focus on this particular breeding site, we examined the capacity of bird fecal matter (BFM) from the spotted dove, to support Aedes albopictus larval growth. The impact of BFM larval uptake on some adult fitness traits influencing vectorial capacity was also investigated. In serial bioassays involving a high and low larval density (HD and LD), BFM and larval standard food (LSF) affected differently larval development. At HD, development was longer in the BFM environment. There were no appreciable mortality differences between the two treatments, which resulted in similar pupation and adult emergence successes. BFM treatment produced a better gender balance. There were comparable levels of blood uptake and egg production in BFM and LSF females at LD; that was not the case for the HD one, which resulted in bigger adults. BFM and LSF females displayed equivalent lifespans; in males, this parameter was shorter in those derived from the BFM/LD treatment. Taken together these results suggest that bird defecations successfully support the development of Ae. albopictus. Due to their cryptic aspects, containers used to supply water to encaged birds may not have been targeted by chemical interventions.
    Matched MeSH terms: Dengue/epidemiology*
  16. Mohamad M, Selamat MI, Ismail Z
    J Environ Public Health, 2014;2014:459173.
    PMID: 25309602 DOI: 10.1155/2014/459173
    In order to reduce the risk of dengue outbreak recurrence in a dengue outbreak prone area, the members of the community need to sustain certain behavior to prevent mosquito from breeding. Our study aims to identify the factors associated with larval control practices in this particular community. A cross-sectional study involves 322 respondents living in a dengue outbreak prone area who were interviewed using a pretested questionnaire. The level of knowledge about Aedes mosquitoes, dengue transmission, its symptoms, and personal preventive measures ranges from fair to good. The level of attitude towards preventive measures was high. However, reported level of personal larval control practices was low (33.2%). Our multiple logistic regression analysis showed that only those with a good level of attitude towards personal preventive measure and frequent attendance to health campaigns were significantly associated with the good larval control practices. We conclude that, in a dengue outbreak prone area, having a good attitude towards preventive measures and frequent participation in health campaigns are important factors to sustain practices on larval control.
    Matched MeSH terms: Dengue/epidemiology*
  17. Aziz S, Aidil RM, Nisfariza MN, Ngui R, Lim YA, Yusoff WS, et al.
    J Vector Borne Dis, 2014 Jun;51(2):91-6.
    PMID: 24947215
    Dengue fever (DF) is a major vector-borne disease in Malaysia. The incidences of DF in Malaysia are caused by viruses transmitted through the bites of infected female Aedes albopictus and Ae. aegypti mosquitoes. This study aims to establish the spatial density of mosquito population or breteau index (BI) in the areas of Kuala Lumpur using geographic information system (GIS), remote sensing (RS) and spatial statistical tools.
    Matched MeSH terms: Dengue/epidemiology*
  18. Wong LP, AbuBakar S, Chinna K
    PLoS Negl Trop Dis, 2014 May;8(5):e2789.
    PMID: 24853259 DOI: 10.1371/journal.pntd.0002789
    Demographic, economic and behavioural factors are central features underpinning the successful management and biological control of dengue. This study aimed to examine these factors and their association with the seroprevalence of this disease.
    Matched MeSH terms: Dengue/epidemiology
  19. Teoh BT, Sam SS, Tan KK, Johari J, Shu MH, Danlami MB, et al.
    BMC Evol. Biol., 2013;13:213.
    PMID: 24073945 DOI: 10.1186/1471-2148-13-213
    Recurring dengue outbreaks occur in cyclical pattern in most endemic countries. The recurrences of dengue virus (DENV) infection predispose the population to increased risk of contracting the severe forms of dengue. Understanding the DENV evolutionary mechanism underlying the recurring dengue outbreaks has important implications for epidemic prediction and disease control.
    Matched MeSH terms: Dengue/epidemiology*
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