Displaying publications 381 - 400 of 471 in total

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  1. Fulltext Mosquito larvicidal potential of tropical seaweeds: acetylcholinesterase inhibitory effects of bryopsis pennata, padina australis and sargassum binderi on Aedes aegypti (L.) and Aedes albopictus skuse
    Ke-Xin Yu, Rohani Ahmad, Ching-Lee Wong, Ibrahim Jantan
    Malaysian Journal of Medicine and Health Sciences, 2020;16(101):125-130.
    MyJurnal
    Introduction: Inhibition of the cholinesterase’s function leads to paralysis and death. This mechanism is served as a common mode of action of insecticide. The three tropical seaweeds, namely Bryopsis pennata, Padina australis and Sargassum binderi were reported for its potential mosquito larvicidal effect. In the present study, these seaweeds were evaluated for their potential as a cholinesterase inhibitor in the mechanism of larvicidal action. Methods: Ace- tylcholinsterase (AChE) inhibition assay was carried out based on the colorimetric method using a microplate reader. Phytochemical content of the seaweed extracts was screened by using liquid chromatography-mass spectroscopy (LC-MS). Results: Green seaweed B. pennata showed the strongest inhibition effect towards in vitro AChE by using
    tissue homogenates of Aedes aegypti (IC50 value = 0.84 mg mL ) and Aedes albopictus as the enzyme source (IC
    -1
    value = 0.92 mg mL-1). The pattern of Lineweaver-Burk plots revealed that B. pennata was a mixed type inhibitor of
    AChE, as the readings of Km, Vmax, Ki and Ki’, indicates that it had a strong inhibition ability with high binding affin- ity towards both free enzyme and enzyme-substrate complex. Conclusion: These findings suggest the compound(s) in
    B. pennata extract serves as a promising source that could be developed into a mosquito larvicidal agent with AChE inhibition effect.
    Matched MeSH terms: Aedes
  2. Fulltext Phytochemical screening and larvicidal activity of murraya koenigii leaves ethanolic extract against aedes aegypti
    Norazsida Binti Ramli, Nur Elia Amira Mohd Roslin, Deny Susanti
    International Journal of Allied Health Sciences, 2018;2(1):129-139.
    MyJurnal
    World Health Organization (WHO) estimated over 100 million dengue infections to happen annually worldwide involving more than 2.5 billion people. Temephos or abate is a larvicide that has been used in vector control to eradicate mosquito larvae. Though practically low risk, there had been resistance problem reported with continuous use. This study seeks to find an effective and safer alternative to abate by assessing the use of ethanolic extract of Murraya koenigii leaves as larvicidal agent against Aedes aegypti. M.koenigii leaves were macerated for 3 days with absolute ethanol and evaporated using rotary vapor to produce the crude extract. The crude extract was subjected to phytochemical screening using standard qualitative method. For bioassay, the crude
    extract underwent a serial dilution to produce 3 concentrations of 100 ppm (C1), 50 ppm (C2) and 10 ppm (C3) with abate and absolute ethanol as negative and positive control respectively. Bioassay for larvicidal effect was conducted in accordance to WHO standard method. Phytochemical screening of ethanolic extract of M. koenigii leaves revealed the presence of alkaloid, steroid and saponin. The bioassay shows that after 24 hours, the mortality rate of C1, C2 and C3 larvae were 100%, 38% and 0% and when further extended to 48 hours, the rate increased to 100% and 46% for C2 and C3 respectively. The LC50 and LC99 post 24 hours were 54.489 ppm and 93.961 ppm respectively whilst at post 48 hours, the LC50 and LC99 were 10.263 ppm and 16.176 ppm respectively. The results show that up to 48 hours duration of exposure, the mortality
    rate increase whilst the lethal concentration (LC50 and LC99) decreases. Upon examination on larvae deformities at post 24 and 48 hours, all test concentrations and negative control exhibit normal morphology. Positive control, however, exhibit deformities characterized by twisted and fragmented insides. When statistically analyzed, C1 larvicidal activity was proven comparable with abate at 24 hours while C2 needed 48 hours exposure to be on par. Based on the results, it could be argued that the ethanolic extract of M.koenigii leaves does hold promising value to be further developed as larvicidal.
    Matched MeSH terms: Aedes
  3. Simulating dengue: comparison of observed and predicted cases from generic reaction-diffusion model for transmission of mosquito-borne diseases
    Cynthia Kon Mui Lian, Jane Labadin
    MATEMATIKA, 2019;35(3):309-330.
    MyJurnal
    Dengue is a mosquito-borne disease caused by virus and found mostly in urban and semi-urban areas, in many regions of the world. Female Aedes mosquitoes, which usually bite during daytime, spread the disease. This flu-like disease may progress to severe dengue and cause fatality. A generic reaction-diffusion model for transmission of mosquito-borne diseases was proposed and formulated. The motivation is to explore the ability of the generic model to reproduce observed dengue cases in Borneo, Malaysia. Dengue prevalence in four districts in Borneo namely Kuching, Sibu, Bintulu and Miri are compared with simulations results obtained from the temporal and spatio-temporal generic model respectively. Random diffusion of human and mosquito populations are taken into account in the spatio-temporal model. It is found that temporal simulations closely resemble the general behavior of actual prevalence in the three locations except for Bintulu. The recovery rate in Bintulu district is found to be the lowest among the districts, suggesting a different dengue serotype may be present. From observation, the temporal generic model underestimates the recovery rate in comparison to the spatio-temporal generic model.
    Matched MeSH terms: Aedes
  4. Fulltext Entomological Surveillance on Resistance of Aedes to Aqua K-Otherine at Taman Sri Rugading, Tuaran, Sabah, Malaysia
    Netto, Marcus
    Borneo Journal of Medical Sciences, 2018;12(101):39-0.
    MyJurnal
    Dengue fever and its fatal complications have made a comeback since its control in the 1990’s. The Flavivirus has evolved into 4 serotypes DEN 1,2,3,4 which can be passed on by the mosquitoes for 7 generations for each serotype. This communicable disease is predominantly confined to urban areas. Quick control of the spread of the disease will prevent it from becoming an epidemic. The two species mosquitoes involved have different behaviours. The Aedes aegypti is an indoor vector which breeds in clean, clear and calm freshwater. The Aedes albopictus is an outdoor breeding mosquito which breeds in stagnant waters. Surveillance of the areas prone to outbreaks is vital. One of the roles of the entomologist is to monitor the vector for resistance to the insecticides. Localities that have been subjected to recurrent outbreaks will have vector which develop resistance to the insecticides used.
    Matched MeSH terms: Aedes
  5. The Impact of Sociological and Environmental Factors for Dengue Infection in Kuala Lumpur, Malaysia
    Adnan RA, Ramli MF, Othman HF, Asha'ri ZH, Ismail SNS, Samsudin S
    Acta Trop, 2021 Apr;216:105834.
    PMID: 33485870 DOI: 10.1016/j.actatropica.2021.105834
    BACKGROUND: Dengue incidence has grown dramatically around the world in recent years. Vector control is the only method to reduce dengue incidence due to the lack of a vaccine available. By understanding the factors contributed to the vector densities such as environmental and sociological factors, dengue prevention and control may succeed.

    OBJECTIVE: This study is aimed at determining the impact of sociological and environmental factors contributing to dengue cases.

    METHODS: The study surveyed 379 respondents with dengue history. The socio-environmental factors were evaluated by chi-square and binary regression.

    RESULT: The chi-square results revealed sociological factors associated between family with dengue experience such as older age (p =0.012), fewer than four people in the household (p= 0.008), working people (p= 0.004) and apartment/terrace houses (p=0.023). Similarly, there is a significant association between respondent's dengue history and houses that are shaded with vegetation (p= 0.012) and the present of public playground areas near the residential (p = 0.011).

    CONCLUSION: The study identified socio-environmental factors that play an important role in the abundance of Aedes mosquitoes and also for the local dengue control measures.

    Matched MeSH terms: Aedes
  6. Shifts in mosquito diversity and abundance along a gradient from oil palm plantations to conterminous forests in Borneo
    Young KI, Buenemann M, Vasilakis N, Perera D, Hanley KA
    Ecosphere, 2021 Apr;12(4).
    PMID: 33996190 DOI: 10.1002/ecs2.3463
    Deforestation precipitates spillover of enzootic, vector-borne viruses into humans, but specific mechanisms for this effect have rarely been investigated. Expansion of oil palm cultivation is a major driver of deforestation. Here, we demonstrate that mosquito abundance decreased over ten stepwise distances from interior forest into conterminous palm plantations in Borneo. Diversity in interior plantation narrowed to one species, Aedes albopictus, a potential bridge vector for spillover of multiple viruses. A. albopictus was equally abundant across all distances in forests, forest-plantation edge, and plantations, while A. niveus, a known vector of sylvatic dengue virus, was found only in forests. A. albopictus collections were significantly female-biased in plantation but not in edge or forest. Our data reveal that the likelihood of encountering any mosquito is greater in interior forest and edge than plantation, while the likelihood of encountering A. albopictus is equivalent across the gradient sampled from interior plantation to interior forest.
    Matched MeSH terms: Aedes
  7. Fulltext Co-breeding Association of Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus) (Diptera: Culicidae) in Relation to Location and Container Size
    Hashim NA, Ahmad AH, Talib A, Athaillah F, Krishnan KT
    Trop Life Sci Res, 2018 Mar;29(1):213-227.
    PMID: 29644025 MyJurnal DOI: 10.21315/tlsr2018.29.1.14
    The occurrence of major outbreaks of dengue, and other vector borne diseases such as chikungunya and zika in tropical and subtropical regions has rendered control of the diseases a top-priority for many affected countries including Malaysia. Control of the mosquito vectors Aedes aegypti and Aedes albopictus through the reduction of breeding sites and the application of insecticides to kill immature forms and adults are the main control efforts to combat these diseases. The present study describes the association between Ae. albopictus and Ae. aegypti in shared breeding sites. This study is important given that any measure taken against one species may affect the other. A yearlong larval survey was conducted in four dengue endemic areas of Penang Island. Sorenson's coefficient index indicated that no association between number of the immatures of the two species regardless of container size and study location. Therefore, the mean number Ae. albopictus immature was not decreased in the presence of Ae. aegypti in shared breeding container. However Ae. aegypti appeared to prefer breeding in habitats not occupied by Ae. albopictus, the two species sharing breeding sites only where available containers were limited. In control efforts, eliminating the preferred breeding containers for one species might not affect or reduce the population of the other species.
    Matched MeSH terms: Aedes
  8. Fulltext Adulticidal activity of some Malaysian plant extracts against Aedes aegypti Linnaeus
    Hidayatulfathi O, Sallehuddin S, Ibrahim J
    Trop Biomed, 2004 Dec;21(2):61-7.
    PMID: 16493400
    The adulticidal activity of methanol extracts from three Malaysian plants namely Acorus calamus Linn., Litsea elliptica Blume and Piper aduncum Linn. against adult of Aedes aegypti (L.) were studied. Standard WHO bioassay tests were used to evaluate the effectiveness of these plant extracts. The hexane fraction from methanol extract of Acorus calamus rhizome was the most effective, exhibiting LC50 and LC90 values of 0.04 mgcm(-2) and 0.09 mgcm(-2) respectively. For L. elliptica, the methanol fraction also displayed good adulticidal property with the LC50 and LC90 values of 0.11 mgcm(-2) and 6.08 mgcm(-2) respectively. It is found that hexane fraction of the P. aduncum crude extract was the least effective among the three plants showing LC50 and LC90 values of 0.20 mgcm(-2) and 5.32 mgcm(-2), respectively. However, although A. calamus showed lowest LC values, the LT50 results indicated that the methanol fraction of L. elliptica was most potent extract among the extracts tested.
    Matched MeSH terms: Aedes
  9. Ultrastructural changes of cell morphology and viral morphogenesis of two ecotypes of dengue virus infection in human monocytic U-937 cell
    Fish-Low CY, Abu Bakar S, Othman F, Chee HY
    Trop Biomed, 2018 Dec 01;35(4):1154-1159.
    PMID: 33601863
    Dengue virus (DENV) is maintained and circulated in both sylvatic/enzootic and endemic/human cycles and spill over infection of sylvatic DENV into human populations has been reported. Extensive deforestation and increase human activities in forest may increase the risk of human exposure to sylvatic dengue infection and this may become a threat to human. Present study investigated the changes in cell morphology and viral morphogenesis upon infection with sylvatic and endemic ecotypes in human monocytic U-937 cells using transmission electron microscopy. Autophagy, a process that is either pro-viral or anti-viral, was observed in U-937 cells of both infections, however only the replication of endemic DENV was evidenced. An insight into the infection responses of sylvatic progenitors of DENV in susceptible host cells may provide better understanding on dengue emergence in human populations.
    Matched MeSH terms: Aedes
  10. Genetic structure of the dengue vector Aedes albopictus (Skuse) from different developed settlements in Penang Island, Malaysia based on microsatellite markers
    Muhammad NAF, Kassim NFA, Ab Majid AH, Wajidi MFF, Jamsari AFJ, Dieng H, et al.
    Trop Biomed, 2018 Dec 01;35(4):1049-1063.
    PMID: 33601852
    The medically important mosquito, Aedes albopictus is native to Asia and has become a major health concern in most Asian countries including Malaysia. Being recognized as a dengue vector, a clearer understanding of how mosquito populations are geographically connected, may therefore represent a profound yet significant understanding of control strategies. There are no documented reports on the genetic structure of Ae. albopictus populations from different developed settlements inferred from microsatellite DNA markers in Malaysia, particularly in Penang Island (Northern Peninsular Malaysia). Here, we assessed the molecular population genetics of Ae. albopictus in terms of their allelic variation, genetic diversity and population structure. A total of 42 mosquitoes were sampled from Jelutong, Batu Maung and Balik Pulau which represented urban, suburban and rural areas in Penang Island respectively and analysed for polymorphism at six microsatellite loci. All of the microsatellite markers were successfully amplified and were polymorphic, showing low genetic structure among geographic populations (FST= 0.0362). It is supported with admixture individuals observed in STRUCTURE and FCA and this suggests that high gene flow has been experienced between populations. These findings implicate passive dispersal through human-aided transportation; as a factor shaping the genetic structure of Ae. albopictus populations in Penang Island.
    Matched MeSH terms: Aedes
  11. Biogenic larvicidal formulation of metabolites from Steinernema saimkayi symbiont Xenorhabdus stockiae KUT6 against dengue vector Aedes aegypti
    Jissin M, Vani C
    Trop Biomed, 2020 Sep 01;37(3):791-802.
    PMID: 33612792 DOI: 10.47665/tb.37.3.791
    To characterize the production and larvicidal activity of Xenorhabdus stockiae KUT6 Petroleum ether extracts from Luria Broth and induced Quorum sensing medium containing N-3- oxododecanoyl Homoserine Lactone inducer against dengue vector Aedes aegypti. The Galleria mellonella larvae were reared for the isolation of Steinernema saimkayi symbiont Xenorhabdus stockiae KUT6 from Cucumber field soil sample in NBTA. Then for the extraction of compounds the KUT6 strains were cultured in Luria Broth and Quorum Sensing optimized media using N-3-oxododecanoyl homoserine lactone inducer. The larvicidal activity of Xenorhabdus stockiae KUT6 of petroleum ether extracts were bioassayed against 4th instar Aedes aegypti dengue vector. The maximum rate of mortality were recorded of the samples A-24h, B-48h, C-72h, A1-24h, B1-48h, C1-72h at different concentrations 50 µg/ml, 100 µg/ml and 150 µg/ml respectively for 24h to 72h of exposure treatment. The morphological characteristics of Xenorhabdus stockiae KUT6 in NBTA were red core colonies with blue background surrounded by zone of inhibition. After 24h exposure maximum rate of 100% mortality of Aedes aegypti 4th instar larvae was attained when treated with sample C1-72h 50 µg/ml of the petroleum ether extracts of quorum sensed medium whereas the sample C 72h petroleum ether extracts of KUT6 cultured in Luria broth recorded 100% mortality at 150 µg on 24h exposure indicates enhancement in the product yield. The study assures the use of Xenorhabdus stockiae KUT6 petroleum ether extracts as biocontrol agent could be beneficial for the control of dengue vectors.
    Matched MeSH terms: Aedes
  12. Fulltext Outbreak of dengue in Bandar Baru Bangi
    Meftahuddin, T., Anisah, A.B., Mohd Faizal, A.
    Malaysian Journal of Public Health Medicine, 2004;4(1):22-28.
    MyJurnal
    An outbreak of dengue and dengue haemorrhagic fever was studied in Bandar Baru Bangi, Hulu Langat District which started from epidemiological week 51 of December 2001 until ]anuary 2002. Altogether, 53 cases were reported to the Hulu Langat District Health Office with 24 cases detected in Section I and Section 6, and 5 cases in Section 4 of Bandar Baru Bangi respectively. Two cases were confirmed as dengue haernorrhagic fever (DHF). The majority of the cases were female Malays. The age of the cases ranged from 3 to 60 years with a mean of 29.17 : 13.18 years old. The majority of patients were mainly private sector workers from factories or companies with 29 cases (54.7%) and university students with 14 cases (26.4%). No deaths were reported in this outbreak. On the average, the duration taken for a patient to be admitted from the date of onset was about 4.4 - 2.0 days and the duration taken for notification from the date of admission was about 2.0 - 1.7 days. The majority of cases reported were based on classical clinical features of dengue fever. Only 18 cases (34%) were IgM positive for dengue. The statistical analysis showed that the majority were male (P>0.05), Malays (P>0.05) , age group of 21»30 years (P>0.05), platelets level < 100,000 per mm3 (p>0.05) and the serological specimens obtained 5 days after the date of onset (p2.0%) within residential premises in this locality with 46 Aedes mosquito breeding places identified and a total amount of RM 6500 of fines imposed.
    Matched MeSH terms: Aedes
  13. Fulltext New Paradigms for Virus Detection, Surveillance and Control of Zika Virus Vectors in the Settings of Southeast Asia
    Vythilingam I, Sam JI, Chan YF, Khaw LT, Sulaiman WY
    Front Microbiol, 2016;7:1452.
    PMID: 27679623 DOI: 10.3389/fmicb.2016.01452
    Zika virus (ZIKV) has now become a global public health concern. The vectors for ZIKV are Aedes aegypti and A. albopictus. Both these mosquitoes are predominant in Southeast Asia and are also responsible for the spread of other arboviral diseases like dengue virus and chikungunya virus. The incidence of dengue has been increasing over the years and this is of concern to public health workers. Simple laboratory tools for the detection of ZIKV is also lacking. In the absence of drugs and vaccine for these arboviral diseases, vector control is the main option for surveillance and control. Aedes larval surveys have been the hallmark of dengue control along with larviciding and fogging when cases are reported. However, we need new paradigms and options for control of these vectors. The current situation in Southeast Asia clearly proves that effective strategies for vector control need to be proactive and not reactive. This will be the way forward to control epidemics of these diseases inclusive of ZIKV until a vaccine becomes available.
    Matched MeSH terms: Aedes
  14. Fulltext Community vulnerability on dengue and its association with climate variability in Malaysia: a public health approach
    Mazrura, S., Rozita Hod, Hidayatulfathi, O., Zainudin, M.A., Mohamad Naim, M.R., Nadia Atiqah, M.N., et al.
    Malaysian Journal of Public Health Medicine, 2010;10(2):25-34.
    MyJurnal
    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.
    Matched MeSH terms: Aedes
  15. Chemical constituents from Garcinia maingayi and Garcinia paroifolia (Guttiferae) and their biological activities
    Ee, G.C.L., Cheow, Y.L.
    Pertanika Journal of Science & Technology, 2007;15(2):95-102.
    MyJurnal
    Detail chemical studies on Carcinia maingayi have yielded one xanthone, 1,3,7-trihydroxy-2-(3-methylbut-2-enyl)-xanthone, one benzophenone, isoxanthochymol, one benzoic acid derivative 3,4-dihydroxy-methylbenzoate and two triterpenoids, stigmasterol and sitosterol. Meanwhile, investigations on Carcinia parvifolia have afforded one triterpenoid, a-amyrin and two xanthones, cowanin and rubraxanthone. Their structures were derived based on spectroscopic evidence, mainly ID and 2D NMR spectroscopy. Acetylation reaction was carried out on rubraxanthone to yield triacetate rubraxanthone. It was found that the pure rubraxanthone was strongly active against the larvae of Aedes aegypti with LC50 value of 15.49 {lg/ ml and HL-60 cells line with an IC50 value of 7.5 {lg/ ml.
    Matched MeSH terms: Aedes
  16. Fulltext Pyrethroid resistance status of Aedes (Stegomyia) aegypti (Linneaus) from dengue endemic areas in Peninsular Malaysia
    Rosilawati, R., Lee, H.L., Nazni, W.A., Nurulhusna, A.H., Roziah, A., Khairul Asuad, M., et al.
    International Medical Journal Malaysia, 2017;16(2):73-78.
    MyJurnal
    Vector control is still the principal method to control dengue and chemical insecticides, especially the
    pyrethroids such as permethrin are the forerunners of mosquito control agent. Intensive and extensive use
    of pyrethroids often result in resistance, thereby hampering control efforts. The present study was
    conducted to evaluate the susceptible status of Aedes aegypti, the primary vector of dengue against
    permethrin. A nationwide mosquito sampling via ovitrapping was conducted in 12 dengue hotspots across 5
    states in Peninsular Malaysia. Field collected Aedes eggs were hatched and reared until L3 larval and further
    identified it species. Adult F0 Aedes aegypti were reared until F1 progeny and the female were used in
    adult assay, performed according to World Health Organization (WHO) protocol as to determine the
    resistance level. The laboratory strain maintained for more than 1000 generations that were susceptible to
    permethrin served as the control strain. Evaluation of resistance ratio was assessed by comparing the
    knockdown rate with laboratory susceptible strain. In this present study, 70% ofAe. aegypti population from
    dengue hotspots was highly resistance to permethrin. The study clearly demonstrated that widespread of
    permethrin resistant Ae. aegypti in Malaysian mosquito’s population, indicating the need of implementing
    an efficient pyrethroid resistance management.
    Matched MeSH terms: Aedes
  17. Fulltext Viral Determinants and Vector Competence of Zika Virus Transmission
    Tham HW, Balasubramaniam V, Ooi MK, Chew MF
    Front Microbiol, 2018;9:1040.
    PMID: 29875751 DOI: 10.3389/fmicb.2018.01040
    Zika virus (ZIKV) has emerged as a new global health threat. Since its first discovery in Zika forest in Uganda, this virus has been isolated from several mosquito species, including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America. This has gained attention of the scientific community to elucidate the epidemiology and transmission of ZIKV. Despite its strong attention on clinical aspects for healthcare professionals, the relationships between ZIKV and its principal vectors, A. aegypti and A. albopictus, have not gained substantial interest in the scientific research community. As such, this review aims to summarize the current knowledge on ZIKV tropism and some important mechanisms which may be employed by the virus for effective strategies on viral survival in mosquitoes. In addition, this review identifies the areas of research that should be placed attention to, for which to be exploited for novel mosquito control strategies.
    Matched MeSH terms: Aedes
  18. Fulltext Screening of five plant extracts for larvicidal efficacy against larvae of Aedes aegypti (L.) and Aedes albopictus (Skuse)
    Azlinda Abu Bakar, Sallehudin Sulaiman, Baharudin Omar, Rasadah Mat Ali
    ASM Science Journal, 2018;11(2):103-116.
    MyJurnal
    The adverse effects of prolonged and rampant usage of chemical insecticides in controlling the population of vector arthropod have caused the development of resistance among vector populations as well as non-target organism. Application of plant extracts could be alternative sources for mosquito control. The present study assessed larvicidal activities of methanol extracts of leaf and stem of Jacaranda mimosifolia Don (Family: Bignoniaceae), Melaleuca cajuputi Powell (Family: Myrtaceae), Tabebuia chrysantha (Jacq.) Nicholson (Family: Bignoniaceae), Tabebuia pallida (Lindl.) Miers (Family: Bignoniaceae) and Tabebuia rosea Toll (Family: Bignoniaceae) against dengue vectors, Aedes (Diptera: Culicidae) sp. Among plants tested, M. cajuputi exhibited the most effective with the highest mortality against Ae. aegypti and Ae. albopictus. Leaf extracts showed significantly higher larvicidal effects in relative to stem extracts. The findings also revealed that Ae. aegypti is the most susceptible compared to Ae. albopictus. LC50 values of M. cajuputi leaf extracts were 183.35mg/L and 191.82mg/L against Ae. aegypti and Ae. albopictus respectively. These studies suggest leaf extracts of M. cajuputi have moderate potential as larvicidal against vector larvae of Aedes mosquitoes.
    Matched MeSH terms: Aedes
  19. Fulltext Population structure and genetic diversity of Aedes aegypti and Aedes albopictus in Penang as revealed by mitochondrial DNA cytochrome oxidase I
    Md Naim D, Kamal NZM, Mahboob S
    Saudi J Biol Sci, 2020 Mar;27(3):953-967.
    PMID: 32127775 DOI: 10.1016/j.sjbs.2020.01.021
    The population genetics study is crucial as it helps in understanding the epidemiological aspects of dengue and help improving a vector control measures. This research aims to investigate the population genetics structure of two common species of Aedes mosquitoes in Penang; Aedes aegypti and Aedes albopictus using Cytochrome Oxidase I (COI) mitochondrial DNA (mtDNA) marker. Molecular investigations were derived from 440 bp and 418 bp mtDNA COI on 125 and 334 larvae of Aedes aegypti and Aedes albopictus respectively, from 32 locations in Penang. All samples were employed in the BLASTn for species identification. The haplotype diversity, nucleotide diversity, neutrality test and mismatch distribution analysis were conducted in DnaSP version 5.10.1. AMOVA analysis was conducted in ARLEQUIN version 3.5 and the phylogenetic reconstructions based on maximum likelihood (ML) and neighbor-joining (NJ) methods were implemented in MEGA X. The relationships among haplotypes were further tested by creating a minimum spanning tree using Network version 4.6.1. All samples were genetically identified and clustered into six distinct species. Among the species, Ae. albopictus was the most abundant (67.2%), followed by Ae. aegypti (25.2%) and the rest were counted for Culex sp. and Toxorhynchites sp. Both Ae. aegypti and Ae. albopictus show low nucleotide diversity (π) and high haplotype diversity (h), while the neutrality test shows a negative value in most of the population for both species. There are a total of 39 and 64 haplotypes recorded for Ae. aegypti and Ae. albopictus respectively. AMOVA analysis revealed that most of the variation occurred within population for both species. Mismatch distribution analysis showed bimodal characteristic of population differentiation for Ae. aegypti but Ae. albopictus showed unimodal characteristics of population differentiation. Genetic distance based on Tamura-Nei parameter showed low genetic divergent within population and high genetic divergent among population for both species. The maximum likelihood tree showed no obvious pattern of population genetic structure for both Ae. aegypti and Ae. albopictus from Penang and a moderate to high bootstrap values has supported this conclusion. The minimum spanning network for Ae. aegypti and Ae. albopictus showed five and three dominant haplotypes respectively, which indicates a mixture of haplotypes from the regions analysed. This study revealed that there is no population genetic structure exhibited by both Ae. aegypti and Ae. albopictus in Penang. Mutation has occurred rapidly in both species and this will be challenging in controlling the populations. However, further analysis needed to confirm this statement.
    Matched MeSH terms: Aedes
  20. Fulltext The association between climatic factors and dengue fever: a study in Subang Jaya and Sepang, Selangor
    Nik Syaza Lina Nik Ruzman, Haliza Abdul Rahman
    Malaysian Journal of Public Health Medicine, 2017;17 Special(1):140-150.
    Dengue fever is one of the most dangerous vector-borne diseases. According to the World Health Organization (WHO), dengue fever is a mosquito-borne infection caused by virus serotype DEN-1, DEN-2, DEN-3 and DEN-4. In Malaysia, dengue fever cases are on the rise from 6,000 cases in 1995 to over 40,000 in 2010, and this number is still rising. In 2014, the increase of dengue fever cases was alarming. It was reported that up to the end of the year 2014, there were 108,698 notified cases, indicating an increment of 151% compared to the same period of time in 2013 with only 43,346 reported cases. Selangor was the highest contributor of dengue fever cases in 2014. The objective of this paper is to study the relationship between climatic factors namely temperature, rainfall and humidity to the prevalence of dengue fever in Subang Jaya and Sepang district, Selangor. Data on monthly average temperature, precipitation, relative humidity and dengue fever cases for each month in 2014 and 2013 were collected. Data collection was dealt with a few institutions such as Malaysian Meteorological Department, Subang Jaya and Sepang Municipal Council and health district offices. Data were analysed using SPSS (Statistical Package for the Social Sciences) Version 20. General linear model analysis was used to investigate the relationship between the climatic variables and dengue prevalence. Results and Discussion: Based on the general linear model, rainfall and humidity were found to have significant relationships to monthly dengue fever cases (p= <0.001, p= 0.002). Rainfall was identified as the most significant predictor because rainfall can provide more breeding places for Aedes mosquitoes. As for humidity, higher relative humidity had been associated with increased Aedes aegypti feeding activity, survival and egg development. Temperature was not significantly related to monthly dengue fever cases (p= 0.561) in this study. However, this could be due to the short period of study. Conclusion: Climatic factors play an important role in the prevalence of dengue fever. However, there are many other factors of dengue fever that should be considered such as urbanisation as well as community knowledge, attitude and practice.
    Matched MeSH terms: Aedes
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