Displaying publications 1 - 20 of 42 in total

  1. Cheong WH
    Med J Malaya, 1968 Mar;22(3):242.
    PMID: 4234377
    Matched MeSH terms: Aedes/growth & development*
  2. Cheong WH
    Bull. World Health Organ., 1967;36(4):586-9.
    PMID: 5299457
    Matched MeSH terms: Aedes/growth & development*
  3. Selvarajoo PD, Haque RA, Haziz UFM, Avicor SW, Wajidi MFF, Razali MR
    J. Inorg. Biochem., 2017 10;175:232-238.
    PMID: 28800547 DOI: 10.1016/j.jinorgbio.2017.07.030
    New synthesized bis-imidazolium salts that are linked by xylyl derivatives moiety, 1-4 was reacted with Ag2O to facilitate the formation of dinuclear Ag(I)-N-heterocyclic carbene (NHC) complexes, 5-8, respectively. All the synthesized ligand salts and complexes were characterized by1H and13C NMR, FTIR spectroscopy and elemental analysis. Molecular structures of compounds 3, 5, and 7 were elucidated by single crystal X-ray diffraction analyses. Larvicidal studies against the Aedes aegypti and Culex quinquefasciatus were carried out on all synthesized compounds following the World Health Organization standard larval susceptibility test. All the imidazolium salts were found inactive while the activity of the dinuclear Ag(I)-NHC complexes on mosquito larvae are varies with the nature of the ligands. Complex 7 has high activity on Ae. aegypti and Cx. quinquefasciatus, emphasising its potential as a larvicidal compound.
    Matched MeSH terms: Aedes/growth & development*
  4. Lau KW, Chen CD, Lee HL, Izzul AA, Asri-Isa M, Zulfadli M, et al.
    Trop Biomed, 2013 Mar;30(1):36-45.
    PMID: 23665706 MyJurnal
    The aim of the present study was to determine the vertical distribution and abundance of Aedes mosquitoes in multiple storey buildings in Selangor and Kuala Lumpur, Malaysia. Ovitrap surveillance was conducted for 4 continuous weeks in multiple storey buildings in 4 residential areas located in Selangor [Kg. Baiduri (KB)] and Kuala Lumpur [Student Hostel of University of Malaya (UM), Kg. Kerinchi (KK) and Hang Tuah (HT)]. The results implied that Aedes mosquitoes could be found from ground floor to highest floor of multiple storey buildings and data from different elevation did not show significant difference. Ovitrap index for UM, KB, HT and KK ranged from 0 - 29.17%, 0 - 55.56%, 8.33 - 83.33% and 0 - 91.17% respectively. Aedes aegypti and Aedes albopictus were found breeding in HT, KK and KB; while only Ae. albopictus was obtained from UM. The results indicate that the invasion of Aedes mosquitoes in high-rise apartments could facilitate the transmission of dengue virus and new approaches to vector control in this type of residential area should be developed.
    Matched MeSH terms: Aedes/growth & development*
  5. Seleena P, Lee HL, Chiang YF
    J. Vector Ecol., 1999 Dec;24(2):216-23.
    PMID: 10672551
    The compatibility of the commercial aqueous Bacillus thuringiensis serovar israelensis (B.t.i.) formulation, Vectobac 12AS, with the chemical insecticides Actellic 50EC, Aqua Resigen, Resigen, and Fendona SC, for the simultaneous control of Aedes larvae and adults was studied by dispersing nine different formulations using a portable mist blower, in single story half-brick houses. The effectiveness of the treatment was evaluated by measuring the larval mortality, adult mortality, and droplet analysis at varying distances from the sprayer. Persistence of the larvicidal activity of the chemical insecticides and B.t.i was also determined by measuring the larval mortality in the test samples 7 days posttreatment. The sprayed particles in all the trials were 50-60 microns in size, indicating that the particles were those of mist spray. Test samples placed within 3 m from the sprayer gave the maximum larval and adult mortality. Chemical insecticides exhibited maximum larval mortality in the 1 h posttreatment test samples and it was comparable to the larvicidal activity of B.t.i. The larvicidal toxins of B.t.i were more stable and were able to affect sufficient larval mortality for 7 days posttreatment. The larvicidal activity of the mixtures, i.e., chemical insecticides with B.t.i, in the 1 h posttreatment test samples was not significantly different from the larvicidal activity of the chemical insecticides and it was comparable to the larvicidal activity of B.t.i alone. However, the larvicidal activity of the mixtures was significantly more than the chemical insecticides alone in the 7 days posttreatment test samples except for the Actellic 50EC and Vectobac 12AS mixture. In all the trials, with or without B.t.i, there was no significant difference in adult mortality, indicating that this B.t.i formulation, Vectobac 12AS, was not antagonistic to the adulticidal activity of the chemical insecticides. From this study, it can be concluded that chemical insecticides can be used effectively for both adult and larval control, but the chemical insecticides do not exhibit residual larvicidal activity. Hence, for an effective control of both Aedes larvae and adults, it is advisable to add B.t.i. to the chemical insecticides, as B.t.i is specifically larvicidal and is also able to effect extended residual larvicidal activity.
    Matched MeSH terms: Aedes/growth & development*
  6. Sulaiman S, Jeffery J
    J. Am. Mosq. Control Assoc., 1994 Sep;10(3):460-1.
    PMID: 7807097
    Between April 1987 and March 1988, populations of immature Aedes albopictus and Toxorhynchites spp. in bamboo pots were sampled weekly. Populations of Ae. albopictus and rainfall varied from month to month. During the heavy rainfall months of September and October 1987, larval counts of Ae. albopictus were high, between 30.8 and 49.2 larvae per week compared to 16 larvae per week during the low rainfall month of January 1988. A higher population of Toxorhynchites spp. was associated with a low population of the vector.
    Matched MeSH terms: Aedes/growth & development
  7. Jong ZW, Kassim NFA, Naziri MA, Webb CE
    J. Vector Ecol., 2017 06;42(1):105-112.
    PMID: 28504428 DOI: 10.1111/jvec.12244
    The fundamental approach to the biological control of Aedes albopictus requires the mass rearing of mosquitoes and the release of highly competitive adults in the field. As the fitness of adults is highly dependent on the development of immatures, we aimed to identify the minimum feeding regime required to produce viable and competitive adults by evaluating three response parameters: development duration, immature mortality, and adult wing length. Our study suggests at least 0.60 mg/larva/day of larval diet composed of dog food, dried beef liver, yeast, and milk powder in a weight ratio of 2:1:1:1 is required to maximize adult fitness. With standardized protocols in mass rearing, intensive studies can be readily conducted on mosquito colonies to facilitate comparisons across laboratories. This study also evaluated the differences in response of laboratory and field strains under different feeding regimes. We found that strain alone did not exert substantial effects on all response parameters. However, the field strain exhibited significantly lower immature mortality than the laboratory strain under the minimum feeding regime. Females and males of the laboratory strain had longer wing lengths under nutritional constraint due to the higher mortality that resulted in reduced interactions with the remaining larvae. Meanwhile, the field strain exhibited heterogeneous duration of immature development compared with the laboratory strain. The disparities demonstrated by the two strains in this study suggest the effect of inbreeding surfaced after a long term of laboratory colonization. Despite the trade-offs resulting from laboratory colonization, the competitiveness of the laboratory strain of Ae. albopictus is comparable to the field strain, provided the larvae are fed optimally.
    Matched MeSH terms: Aedes/growth & development*
  8. Norzahira R, Hidayatulfathi O, Wong HM, Cheryl A, Firdaus R, Chew HS, et al.
    Trop Biomed, 2011 Apr;28(1):48-54.
    PMID: 21602768 MyJurnal
    Ovitrap surveillance was conducted in methodically selected areas in Bentong, Pahang, Malaysia from June 2008 till December 2009 in order to identify insular sites with stable Aedes aegypti population. Eleven sites were surveyed in Bentong district, Pahang, and one of these locations (N3º33' E101º54') was found to have an ovitrap index of Ae. aegypti and Aedes albopictus ranging from 8%-47% and 37%-78% respectively, indicating that this site could be a high-risk area for dengue outbreak. Ae. aegypti larvae were found in both indoor and outdoor ovitraps (p>0.05) while significant difference between the populations of Ae. albopictus larvae from indoors and outdoors was observed (p<0.01). Data collected in this study could provide important entomological information for designing an effective integrated vector control programme to combat Aedes mosquitoes in this area.
    Matched MeSH terms: Aedes/growth & development*
  9. Nyamah MA, Sulaiman S, Omar B
    Trop Biomed, 2011 Aug;28(2):312-9.
    PMID: 22041750
    This study explored the efficacy of Toxorhynchites splendens, predator of Aedes albopictus as a biocontrol agent. There was a negative correlation between Ae. albopictus larval population and Tx. splendens larval population in ovitraps (r=-0.287, R²=0.0821). The correlation is higher between the mean number of Ae. albopictus larvae per ovitrap and the number of Tx. splendens larvae in an ovitrap (r=-0.987, R²=0.9737). Larvae of Tx. splendens were observed to co-exist with larvae of Ae. albopictus and Culex fuscocephala in the ovitraps placed in the study area. The existence of Tx. splendens larvae in the study area coincides with their habit, preferring to breed in bamboo stumps. A total of 480 ovitraps were inspected for 30-week study period and 281 ovitraps were positive with Ae. albopictus larvae respectively. There was a significant difference between numbers of ovitrap positive for Ae. albopictus larvae with number of Tx. splendens larvae in the ovitraps (ANOVA, F((4,475)) 2.655, p<0.05). Of 281 ovitraps positive with Ae. albopictus larvae, 255 ovitraps contained only one Tx. splendens larva each. Only one ovitrap contained four, the most number of Tx. splendens larvae (p< 0.05). Thus, Tx. splendens could be utilised as an alternative for dengue vector control programme.
    Matched MeSH terms: Aedes/growth & development*
  10. Aida HN, Dieng H, Ahmad AH, Satho T, Nurita AT, Salmah MR, et al.
    Asian Pac J Trop Biomed, 2011 Dec;1(6):472-7.
    PMID: 23569816 DOI: 10.1016/S2221-1691(11)60103-2
    OBJECTIVE: To generate life table characteristics for the dengue vector Aedes albopictus (A. albopictus) under uncontrolled conditions, incorporating both the aquatic and the adult stages.

    METHODS: Ten females derived from wild pupae were allowed to fully blood-feed on restrained mice. 774 eggs were hatched in seasoned water. F1 larvae were followed for development until their F2 counterparts emerged as adults. Some population parameters were monitored (F1) or estimated (F2).

    RESULTS: A. albopictus exhibited increased fecundity and egg hatch success. Immature development was quick. Immature survival was high, with lowest rate in the pupal stage. Adult emergence was about 81% and sex ratio was close to 1:1. Generational mortality (K) was about 28%. A high proportion of females completed a reproductive cycle and the obtained parity rate was predicted to lead to higher fecundity in the next generation.

    CONCLUSIONS: It can be concluded that natural A. albopictus populations in Penang seem largely determined by quick development in combination with low immature loss and increased oviposition.

    Matched MeSH terms: Aedes/growth & development*
  11. Aiken SR, Frost DB, Leigh CH
    Soc Sci Med Med Geogr, 1980 Sep;14D(3):307-16.
    PMID: 7455728
    Matched MeSH terms: Aedes/growth & development
  12. Hashim NA, Ahmad AH, Rawi CS, Tahir NA, Basari N
    PMID: 18567442
    Life tables were constructed for twelve cohorts of immature stages of the dengue vector Ae. albopictus in a wooded area of Penang, Malaysia. The development time of Ae. albopictus ranged from 6 to 10 days depending on the mean environmental temperature (r = - 0.639, p < 0.05). Total cohort mortality was correlated with total development time (r = 0.713, p < 0.05) but not temperature (r = -0.477, p > 0.05). Rainfall was correlated with neither development time (r = 0.554, p > 0.05) nor mortality (r = 0.322, p > 0.05). There was a significant difference among the total mortality that occurred in the twelve cohorts (H = 119.783, df = 11, p < 0.05). There was also a significant difference in mortality among the different stages (H = 274.00, df = 4, p < 0.05).
    Matched MeSH terms: Aedes/growth & development*
  13. Rozilawati H, Tanaselvi K, Nazni WA, Mohd Masri S, Zairi J, Adanan CR, et al.
    Trop Biomed, 2015 Mar;32(1):49-64.
    PMID: 25801254 MyJurnal
    Entomological surveillance was conducted in order to determine the abundance and to evaluate any changes of biological vectors or ecology, especially in the dengue outbreak areas. The abundance and breeding preference of Aedes albopictus and Aedes aegypti were conducted in selected dengue outbreak localities in three states of peninsular Malaysia namely Selangor, Federal Territory of Kuala Lumpur, and Penang Island using ovitraps and larval survey method. It was determined that Ae. albopictus was predominant in most of the localities and found to breed more outdoor than indoor. A wide range of breeding foci were recorded in this study. It was also determined that ovitrap method was more effective to detect the presence of Aedes mosquitoes when the larval survey was at low rate of infestation. The abundance of Ae. albopictus in dengue outbreak localities emphasis that the vector control programme should also target this species together with the primary dengue vector, Ae. aegypti.
    Matched MeSH terms: Aedes/growth & development
  14. Ho LY, Loh TS, Yam LA
    Trop Biomed, 2014 Sep;31(3):441-8.
    PMID: 25382470 MyJurnal
    In this study, 13 weeks (October to December 2012) of ovitrap surveillance was conducted in two suburban residential areas in Kampar town, Perak. A total of 17,310 Aedes mosquitoes were found in Taman Kampar Jaya, whereas Taman Juloong recorded a higher number at 19,042. Less than 1% of these were identified as Aedes aegypti, with the remaining confirmed as Aedes albopictus. The female Ae. albopictus were subsequently subjected to WHO standard diagnostic test kits against two pyrethroids (0.05% deltamethrin and 0.75% permethrin) and two organophosphates (1% fenitrothion and 5% malathion). The Ae. albopictus from both research sites were the most susceptible to deltamethrin, recording KT50 and KT95 response values of 15.84 minutes and 16.18 minutes; and 48.18 minutes and 49.44 minutes respectively. This was followed by permethrin (20.57 minutes and 17.52 minutes; 29.54 minutes and 54.54 minutes) and malathion (48.46 minutes and 62.69 minutes; 87.72 minutes and 141.04 minutes). Fenitrothion was found to be least effective towards Ae. albopictus; recording KT50 and KT95 response values of 150.29 minutes and 293.41 minutes for Taman Kampar Jaya, and 203.32 minutes and 408.07 minutes respectively for Taman Juloong. All tested Ae. albopictus showed 100% mortality after 24 hours post exposure. As both residential areas were fogged periodically by the municipal council; alternating between organophosphates and pyrethroids, thus, constant monitoring is crucial in light of the emergence of resistance noted in Ae. albopictus towards fenitrothion.
    Matched MeSH terms: Aedes/growth & development*
  15. Saleeza SN, Norma-Rashid Y, Azirun MS
    PMID: 24450233
    We conducted mosquito surveillance at outdoor breeding habitat in 459 households at 7 urban locations in Putrajaya, Malaysia from January to December 2010 to determine the predominant species and breeding locations. The most common species found at all locations was Aedes albopictus. Gardening utensils were the most common breeding sites. Of the 1,885 mosquito larvae specimens found, 1,774 (94.1%) were Ae. albopictus larvae, 84 (4%) were Ae. aegypti larvae and 27 (1%) were Culex quinquefasciatus larvae. The Aedes index for each of the locations was higher than the goal set by the Ministry of Health for Malaysia. However, the container index at each of the locations was within the goal. The Breateau index was above the goal set by the Ministry of Health at Precinct 9B1 but the other locations were within the goal.
    Matched MeSH terms: Aedes/growth & development*
  16. Wee LK, Weng SN, Raduan N, Wah SK, Ming WH, Shi CH, et al.
    PMID: 23691624
    Two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) were selected to study the population dynamics of Aedes aegypti and Aedes albopictus mosquitoes, vectors of dengue and chikungunya infections. Ovitrap surveillance was conducted between October 2007 and October 2008. There was an inverse negative association between ovitrap index and rainfall at the time of collection, probably because rainfall increased the number of available oviposition sites. Rainfall and ovitrap index were positively associates the 25th day after rainfall occurred. A minor, second peak was observed from the 38th to the 42nd day. The first peak was consistent with the minimum 18-day period between the hatching of eggs to the first oviposition. The second minor peak could be due to the second gonotrophic cycle of the female mosquitoes. Rainfall is an important environmental factor associated with Aedes breeding at the study sites.
    Matched MeSH terms: Aedes/growth & development*
  17. Rohani A, Suzilah I, Malinda M, Anuar I, Mohd Mazlan I, Salmah Maszaitun M, et al.
    Trop Biomed, 2011 Aug;28(2):237-48.
    PMID: 22041742
    Early detection of a dengue outbreak is an important first step towards implementing effective dengue interventions resulting in reduced mortality and morbidity. A dengue mathematical model would be useful for the prediction of an outbreak and evaluation of control measures. However, such a model must be carefully parameterized and validated with epidemiological, ecological and entomological data. A field study was conducted to collect and analyse various parameters to model dengue transmission and outbreak. Dengue prone areas in Kuala Lumpur, Pahang, Kedah and Johor were chosen for this study. Ovitraps were placed outdoor and used to determine the effects of meteorological parameters on vector breeding. Vector population in each area was monitored weekly for 87 weeks. Weather stations, consisting of a temperature and relative humidity data logger and an automated rain gauge, were installed at key locations in each study site. Correlation and Autoregressive Distributed Lag (ADL) model were used to study the relationship among the variables. Previous week rainfall plays a significant role in increasing the mosquito population, followed by maximum humidity and temperature. The secondary data of rainfall, temperature and humidity provided by the meteorological department showed an insignificant relationship with the mosquito population compared to the primary data recorded by the researchers. A well fit model was obtained for each locality to be used as a predictive model to foretell possible outbreak.
    Matched MeSH terms: Aedes/growth & development*
  18. Mangara SG, Sukmono, Kusumadiharja J, Suroso T, Sutjipto H
    PMID: 11414442
    It is known that in Padang, Rantau, Rangsang, Merbau and Bengkalis islands, Riau Province, the deposit of oil was found in a huge quantity. The drilling concession belongs to Kondur Petroleum Company. To operate an exploitation, hundreds of workers not only Indonesian but also the workers from foreign countries come and go to that area. It was recorded that the workers from foreign countries come from Singapore, Malaysia, Thailand, The Philippines, Taiwan, Japan, Korea. United States of America and from France, Britain, Australia and Germany. These workers have a close interaction with about 50,00 local population distributed with a high concentration in some places. The high risk of DHF was determined since the significant density of Aedes aregypti larvae, the main vector of DHF, were found in Lukit, Mengkikip and Melibur, three locations of survey. Of 104 (53.3%) of 195 houses in these three survey locations were found positive for the larvae. Even though there were no positive of larvae in 65 houses in Lukit, in Melibur and Mengkikip, the House Index (HI) was 61.7% and 95.7%. Outside the houses 521 containers were examined in three locations of survey and 329 (63.1%) were positive for Ae. aegypti larvae. The highest number of containers positive for Ae. aegypti larvae were 213 (94.7%) out of 225 and found in Mengkikip. In Melibur, 114 (68.3%) out of 167 of containers were positive and in Lukit only 2 (1.56%) out of 129 containers were positive of Ae. aegypti larvae. These larvae density constitute a high risk of DHF outbreak, and unfortunately is supported by the rainfall situation recorded in Kurau and BZ Climatology Stations. It was recorded that all along the year, at least one day in a month there was the rain which the rainfall volume was 30 ml.
    Matched MeSH terms: Aedes/growth & development*
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