Displaying publications 1 - 20 of 469 in total

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  1. Fulltext A Linkage-Based Genome Assembly for the Mosquito Aedes albopictus and Identification of Chromosomal Regions Affecting Diapause
    Boyle JH, Rastas PMA, Huang X, Garner AG, Vythilingam I, Armbruster PA
    Insects, 2021 Feb 16;12(2).
    PMID: 33669192 DOI: 10.3390/insects12020167
    The Asian tiger mosquito, Aedes albopictus, is an invasive vector mosquito of substantial public health concern. The large genome size (~1.19-1.28 Gb by cytofluorometric estimates), comprised of ~68% repetitive DNA sequences, has made it difficult to produce a high-quality genome assembly for this species. We constructed a high-density linkage map for Ae. albopictus based on 111,328 informative SNPs obtained by RNAseq. We then performed a linkage-map anchored reassembly of AalbF2, the genome assembly produced by Palatini et al. (2020). Our reassembled genome sequence, AalbF3, represents several improvements relative to AalbF2. First, the size of the AalbF3 assembly is 1.45 Gb, almost half the size of AalbF2. Furthermore, relative to AalbF2, AalbF3 contains a higher proportion of complete and single-copy BUSCO genes (84.3%) and a higher proportion of aligned RNAseq reads that map concordantly to a single location of the genome (46%). We demonstrate the utility of AalbF3 by using it as a reference for a bulk-segregant-based comparative genomics analysis that identifies chromosomal regions with clusters of candidate SNPs putatively associated with photoperiodic diapause, a crucial ecological adaptation underpinning the rapid range expansion and climatic adaptation of A. albopictus.
    Matched MeSH terms: Aedes
  2. Fulltext A PRELIMINARY SURVEY ON THE LEVEL OF AWARENESS OF DENGUE CONTROL PROGRAMMES AMONG RESIDENCES IN KUALA TERENGGANU
    Han Shiou Feng, Nur Aida Hashim, Nur Adila Kamaruddin, Nur Syahida Wadhihah Kamarudin, Norasmah Basari
    UMT Journal of Undergraduate Research, 2020;2(1):55-60.
    MyJurnal
    Dengue fever and dengue haemorrhagic fever are diseases caused by dengue virus transmitted by Aedes mosquitoes. Dengue fever has caused a high rate of mortalities among Malaysians every year. Even though many campaigns had been conducted by the government to reduce dengue cases, the number of infected people in this country is still high. We conducted this survey to determine the status of dengue fever awareness among residents in Kuala Terengganu. For data collection, face-to-face interviews were conducted, and a questionnaire was administered. There were three categories of respondents, namely urban area residents, rural area residents and university students. Results showed that respondents across the three groups were knowledgeable regarding dengue fever issues and there was no significant difference between the three categories of respondents in the number of residents who had been involved in dengue awareness programmes. However, most of the respondents regarded the dengue awareness programmes as moderately effective and could be overcome if prevention efforts and approaches were being carried out on a continuous basis.
    Matched MeSH terms: Aedes
  3. Fulltext A comparative study of adult mosquito trapping using dry ice and yeast generated carbon dioxide
    Oli K, Jeffery J, Vythilingam I
    Trop Biomed, 2005 Dec;22(2):249-51.
    PMID: 16883295 MyJurnal
    Adult mosquito collections were conducted for 12 weeks in two residential areas in Kuala Lumpur. The CDC light traps were compared using dry ice and yeast as sources of carbon dioxide attractants for mosquitoes. The efficacy of the dry ice baited trap was significant over yeast generated CO2 trap. The predominant species obtained were Culex quinquefasciatus, Stegomyia albopicta and Armigeres subalbatus.
    Matched MeSH terms: Aedes/physiology
  4. Fulltext A comparison of demographic parameters of Aedes albopictus (skuse) (diptera: culicidae) in dengue risk area at Shah Alam, Selangor
    Ibrahim Ahmed Alhothily, Nazri Che Dom, Siti Aekbal Salleh, Anila Ali
    Malaysian Journal of Medicine and Health Sciences, 2020;16(2):91-98.
    MyJurnal
    Introduction: Aedes albopictus is known for its aggressiveness towards human and recently expanded to more coun- tries 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 esti- mate the dengue outbreak in the current episystem.
    Matched MeSH terms: Aedes
  5. A field trial on the comparative effectiveness of malathion and Resigen by ULV application on Aedes aegypti
    Vythilingam I, Panart P
    Southeast Asian J. Trop. Med. Public Health, 1991 Mar;22(1):102-7.
    PMID: 1948249
    Field trials were conducted in two residential areas of Petaling Jaya Municipality to test the adulticidal and larvicidal effects of malathion 96% TG and Resigen on Aedes aegypti. Malathion is the currently used insecticide in Malaysia for the control of dengue. The Leco HD ULV machine was used throught the trials. For malathion the flow rate was 90 ml/minute at a vehicle speed of 8kph and for Resigen the flow rate was 200 ml/minute at the same vechicle speed. Malathion was more effective giving higher mortality rates when compared with Resigen. The mortality rate of adult Ae. aegypti outdoor was higher than in the living room and kitchen. Both insecticides did not show promising larvicidal effects.
    Matched MeSH terms: Aedes*
  6. A freak specimen of Aedes (Stegomyia) albopictus (Skuse, 1894) from Malaysia (Diptera: Culicidae)
    Rudnick A, Jeffery J, Seng HL, Nee LB
    Southeast Asian J. Trop. Med. Public Health, 1971 Mar;2(1):85-6.
    PMID: 5112345
    Matched MeSH terms: Aedes*
  7. Fulltext A genomic approach to inferring kinship reveals limited intergenerational dispersal in the yellow fever mosquito
    Jasper M, Schmidt TL, Ahmad NW, Sinkins SP, Hoffmann AA
    Mol Ecol Resour, 2019 Sep;19(5):1254-1264.
    PMID: 31125998 DOI: 10.1111/1755-0998.13043
    Understanding past dispersal and breeding events can provide insight into ecology and evolution and can help inform strategies for conservation and the control of pest species. However, parent-offspring dispersal can be difficult to investigate in rare species and in small pest species such as mosquitoes. Here, we develop a methodology for estimating parent-offspring dispersal from the spatial distribution of close kin, using pairwise kinship estimates derived from genome-wide single nucleotide polymorphisms (SNPs). SNPs were scored in 162 Aedes aegypti (yellow fever mosquito) collected from eight close-set, high-rise apartment buildings in an area of Malaysia with high dengue incidence. We used the SNPs to reconstruct kinship groups across three orders of kinship. We transformed the geographical distances between all kin pairs within each kinship category into axial standard deviations of these distances, then decomposed these into components representing past dispersal events. From these components, we isolated the axial standard deviation of parent-offspring dispersal and estimated neighbourhood area (129 m), median parent-offspring dispersal distance (75 m) and oviposition dispersal radius within a gonotrophic cycle (36 m). We also analysed genetic structure using distance-based redundancy analysis and linear regression, finding isolation by distance both within and between buildings and estimating neighbourhood size at 268 individuals. These findings indicate the scale required to suppress local outbreaks of arboviral disease and to target releases of modified mosquitoes for mosquito and disease control. Our methodology is readily implementable for studies of other species, including pests and species of conservation significance.
    Matched MeSH terms: Aedes/classification*; Aedes/genetics*
  8. Fulltext A knowledge attitude and practice (KAP) study on dengue/dengue haemorrhagic fever and the Aedes mosquitoes
    Uma Deavi Ayyamani, Gan CY, Ooi GS
    Med J Malaysia, 1986 Jun;41(2):108-15.
    PMID: 3821605
    A KAP study on dengue/dengue haemorrhagic fever (DF/DHF) was carried out in three areas in the Federal Territory. The three areas were selected based on their ethnic group composition and were Jinjang North (Chinese), Kampung Bahru (Malays) and Sentul (Indians). Houses were selected by a systematic sampling method and house-to-house interviews were carried out with a pre-tested, predesigned questionnaire. 546 (87.62%) of the households responded.
    Matched MeSH terms: Aedes/microbiology*
  9. A knowledge, attitude and practices (KAP) study on dengue among selected rural communities in the Kuala Kangsar district
    Hairi F, Ong CH, Suhaimi A, Tsung TW, bin Anis Ahmad MA, Sundaraj C, et al.
    Asia Pac J Public Health, 2003;15(1):37-43.
    PMID: 14620496
    A cross-sectional survey was conducted to assess the level of knowledge, attitude and practices concerning dengue and its vector Aedes mosquito among selected rural communities in the Kuala Kangsar district from 16-25th June, 2002. It was found that the knowledge of the community was good. Out of the 200 respondents, 82.0% cited that their main source of information on dengue was from television/radio. The respondents' attitude was found to be good and most of them were supportive of Aedes control measures. There is a significant association found between knowledge of dengue and attitude towards Aedes control (p = 0.047). It was also found that good knowledge does not necessarily lead to good practice. This is most likely due to certain practices like water storage for domestic use, which is deeply ingrained in the community. Mass media is an important means of conveying health messages to the public even among the rural population, thus research and development of educational strategies designed to improve behaviour and practice of effective control measures among the villagers are recommended.
    Matched MeSH terms: Aedes/virology
  10. A mosquito survey at Kuala Lumpur airport with special reference to Aedes aegypti
    MACDONALD WW
    Med J Malaya, 1956 Mar;10(3):232-45.
    PMID: 13347454
    Matched MeSH terms: Aedes*
  11. A new anthraquinone from Morinda citrifolia roots
    Ee GC, Wen YP, Sukari MA, Go R, Lee HL
    Nat Prod Res, 2009;23(14):1322-9.
    PMID: 19735047 DOI: 10.1080/14786410902753138
    An investigation of Morinda citrifolia roots afforded a new anthraquinone, 2-ethoxy-1-hydroxyanthraquinone (1), along with five other known anthraquinones: 1-hydroxy-2-methylanthraquinone (2), damnacanthal (3), nordamnacanthal (4), 2-formyl-1-hydroxyanthraquinone (5) and morindone-6-methyl-ether (6). This is the first report on the isolation of morindone-6-methyl-ether (6) from this plant. The structures of these compounds were elucidated based on spectroscopic analyses such as NMR, MS and IR. Biological evaluation of five pure compounds and all the extracts against the larvae of Aedes aegypti indicated 1-hydroxy-2-methylanthraquinone (2) and damnacanthal (3) were the extracts to exhibit promising larvicidal activities.
    Matched MeSH terms: Aedes/drug effects
  12. Fulltext A new paradigm for Aedes spp. surveillance using gravid ovipositing sticky trap and NS1 antigen test kit
    Lau SM, Chua TH, Sulaiman WY, Joanne S, Lim YA, Sekaran SD, et al.
    Parasit Vectors, 2017 Mar 21;10(1):151.
    PMID: 28327173 DOI: 10.1186/s13071-017-2091-y
    BACKGROUND: Dengue remains a serious public health problem in Southeast Asia and has increased 37-fold in Malaysia compared to decades ago. New strategies are urgently needed for early detection and control of dengue epidemics.

    METHODS: We conducted a two year study in a high human density dengue-endemic urban area in Selangor, where Gravid Ovipositing Sticky (GOS) traps were set up to capture adult Aedes spp. mosquitoes. All Aedes mosquitoes were tested using the NS1 dengue antigen test kit. All dengue cases from the study site notified to the State Health Department were recorded. Weekly microclimatic temperature, relative humidity (RH) and rainfall were monitored.

    RESULTS: Aedes aegypti was the predominant mosquito (95.6%) caught in GOS traps and 23% (43/187 pools of 5 mosquitoes each) were found to be positive for dengue using the NS1 antigen kit. Confirmed cases of dengue were observed with a lag of one week after positive Ae. aegypti were detected. Aedes aegypti density as analysed by distributed lag non-linear models, will increase lag of 2-3 weeks for temperature increase from 28 to 30 °C; and lag of three weeks for increased rainfall.

    CONCLUSION: Proactive strategy is needed for dengue vector surveillance programme. One method would be to use the GOS trap which is simple to setup, cost effective (below USD 1 per trap) and environmental friendly (i.e. use recyclable plastic materials) to capture Ae. aegypti followed by a rapid method of detecting of dengue virus using the NS1 dengue antigen kit. Control measures should be initiated when positive mosquitoes are detected.

    Matched MeSH terms: Aedes/physiology*; Aedes/virology*
  13. A new serovar of Bacillus thuringiensis possessing 28a28c flagellar antigenic structure: Bacillus thuringiensis serovar jegathesan, selectively toxic against mosquito larvae
    Seleena P, Lee HL, Lecadet MM
    J Am Mosq Control Assoc, 1995 Dec;11(4):471-3.
    PMID: 8825511
    A novel Bacillus thuringiensis strain highly toxic to mosquitoes was isolated from soil samples in Malaysia. This strain was shown to display a new subfraction of the H-28 flagellar antigen determining a new serovar H28a28c, which was designated serovar jegathesan. Bioassays indicated that Culex quinquefasciatus larvae are the most susceptible to this new isolate, whereas toxicity to Anopheles maculatus and Aedes aegypti larvae was 10 times lower. The potency of this new serotype is also comparable to most of the Malaysian B. thuringiensis H-14 isolates.
    Matched MeSH terms: Aedes*
  14. A note on the interesting eggs of Aedes aurantius
    Cheong WH
    Med J Malaya, 1968 Mar;22(3):242.
    PMID: 4234377
    Matched MeSH terms: Aedes/growth & development*
  15. A note on the preferred A. aegypti breeding habitats in urban areas in Malaysia
    Cheong WH
    Med J Malaya, 1966 Jun;20(4):329-31.
    PMID: 4224347
    Matched MeSH terms: Aedes*
  16. A novel insecticidal serotype of Clostridium bifermentans
    Seleena P, Lee HL, Lecadet MM
    J Am Mosq Control Assoc, 1997 Dec;13(4):395-7.
    PMID: 9474569
    A novel Clostridium bifermentans strain toxic to mosquito larvae on ingestion was isolated from a soil sample collected from secondary forest floor. This strain was designated as serovar paraiba (C. b. paraiba) according to its specific H antigen. Clostridium bifermentans paraiba is most toxic to Anopheles maculatus Theobald larvae (LC50 = 0.038 mg/liter), whereas toxicity to Aedes aegypti (Linn.) (LC50 = 0.74 mg/liter) and Culex quinquefasciatus Say (LC50 = 0.11 mg/liter) larvae was 20 and 3 times lower, respectively. The toxicity to An. maculatus larvae is as high as that of Bacillus thuringiensis serovar israelensis. C. b. paraiba was also found to exhibit significant per os insecticidal activity toward adult Musca domestica (Linn.).
    Matched MeSH terms: Aedes*
  17. A preliminary Aedes aegypti survey
    REID JA
    Med J Malaya, 1954 Dec;9(2):161-8.
    PMID: 14355279
    Matched MeSH terms: Aedes*
  18. A preliminary proteomic study of permethrin resistant and susceptible Aedes aegypti (L.)
    Rosilawati R, Nabila R, Siti Futri Farahininajua F, Nazni WA, Lee HL
    Trop Biomed, 2019 Dec 01;36(4):855-865.
    PMID: 33597458
    The mechanism of insecticide resistance is traditionally attributed to detoxification enzymes, target site alteration, decreased penetration of insecticides and behavioural resistance. Other form of mechanisms, such as the role of protein(s) in resistance is unknown. In the present study, the protein profiling of both IMR-PSS strain (permethrin-selected) and IMR-LS strain (laboratory-susceptible) 24 hours post exposure period to permethrin was carried out via 1D-gel electrophoresis and liquid chromatography mass spectrometry (LC-MS/ MS). The bands which appeared in the gel of 1D-electrophoresis revealed an abundance of proteins. The band pattern of both strains looked macroscopically alike and differed only in band intensity. However, LC-MS/MS analysis revealed that the IMR-PSS strain produced extra 388 peptides that were not found in the IMR-LS strain, indicating that IMR-PSS strain reacted differently from IMR-LS strain as a result of persistent exposure to permethrin. Since the complex banding patterns of 1D-gel electrophoresis were difficult to interpret the significance of the protein difference between IMR-PSS and IMR-LS strain, hence LC-MS/MS analysis is ideally suited for better protein resolution and thus will allow more in-depth comparison of the complex pattern. The findings here provide the first preliminary evidence that insecticide resistance in mosquito induces up regulation of proteins that may be protective to mosquitoes against insecticide and proteins could be another mechanism that contributes to development of resistance.
    Matched MeSH terms: Aedes/genetics*
  19. A preliminary study of dengue infection in Brunei
    Osman O, Fong MY, Devi S
    Jpn J Infect Dis, 2007 Jul;60(4):205-8.
    PMID: 17642533
    The purpose of this study was to examine the extent of dengue infection in Brunei and to determine the predominant serotype circulating in the country. The study generated useful epidemiological data on dengue infection in Brunei. A total of 271 samples from patients suspected of having dengue infections were selected and analyzed. All patients were seen in clinics and hospitals in Brunei. The samples were collected from April 2005 to April 2006 and transported to the WHO Collaborating Centre for Arbovirus Reference and Research, University of Malaya, Malaysia. The following tests were used to achieve the objectives: in-house IgM-capture enzyme-linked immunosorbent assay, virus isolation in mosquito albopictus cell line (C6/36), and viral RNA detection and serotyping by reverse transcriptase-polymerase chain reaction (RT-PCR). The results show that 45 people were positive for dengue-specific IgM (27 males and 18 females), while RT-PCR detected dengue viral RNA in 12 patients, 3 identified as DEN-1 and 9 as DEN-2. Dengue virus was isolated from 6 patients using the C6/36 cell line; 3 were DEN-2 isolates and 3 were DEN-1 isolates. These data show that dengue virus is circulating in Brunei and the predominant infecting serotype for that period was DEN-2 followed by DEN-1. This study is the first to report the detection and isolation of dengue virus from Brunei using RT-PCR and culture in the C6/36 albopictus mosquito cell line.
    Matched MeSH terms: Aedes/virology
  20. Fulltext A preliminary study of the bioactivity of vegetative proteins extracted from Malaysian Bacillus thuringiensis isolates
    Ramasamy B, Nadarajah VD, Soong ZK, Lee HL, Mohammad SM
    Trop Biomed, 2008 Apr;25(1):64-74.
    PMID: 18600206
    Vegetative proteins from Malaysian strains of Bacillus thuringiensis israelensis strains (Bt 11, Bt 12, Bt 15, Bt 16, Bt 17, Bt 21 and Bt 22) and Bacillus sphaericus H-25 strains (Bs 1 and Bs 2) were screened for haemolytic, cytotoxic and larvicidal activity. SDS-PAGE profiles of the Bacillus thuringiensis strains studied consistently showed major bands of 33-37 kDa and 47 kDa. Bt 16 also showed two bands of 66 kDa and 45 kDa similar to the previously reported binary vegetative protein, Vip1Ac (66 kDa) and Vip 2Ac (45 kDa). Both the Bacillus sphaericus strains showed a 35 kDa band that was similiar to a previously reported vegetative protein, the Mtx2 protein. Bs 2 also contains a 37 kDa band, similar to another vegetative protein, the Mtx 3 protein. With the exception of Bt 17 and Bt 21, vegetative proteins from all Bacillus thuringiensis and Bacillus sphaericus strains were highly haemolytic to human erythrocytes, causing more than 75% haemolysis at the highest concentration of 200 microg/ml. High haemolytic activity was associated with high cytotoxic activity with most of the haemolytic strains being indiscriminately cytotoxic to both CEM-SS (human T lymphoblastoid) and HeLa (human uterus cervical cancer) cell lines. Interestingly, the less haemolytic vegetative proteins from Bt 17 and Bt 21 demonstrated cytotoxic activity comparable to that of the highly haemolytic vegetative proteins. Bt 21 displayed toxicity towards both cell lines while Bt 17 was more toxic towards CEM-SS cells. Bioassay against Aedes aegypti and Culex quinquefasciatus larvae revealed that vegetative proteins from the Bacillus thuringiensis strains had activity against both species of larvae but vegetative proteins from Bacillus sphaericus were weakly larvicidal towards Cx. quinquefasciatus only.
    Matched MeSH terms: Aedes/drug effects*; Aedes/growth & development
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