Displaying publications 61 - 80 of 298 in total

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  1. Filariasis in Bengkoka Peninsula, Sabah, Malaysia: bionomics of Mansonia sp
    Chiang GL, Cheong WH, Samarawickrema WA
    Southeast Asian J. Trop. Med. Public Health, 1984 Sep;15(3):294-302.
    PMID: 6151743
    Studies on age groups within activity cycles, age composition and survivorship in natural populations of Mansonia in Kampung Pantai, Bengkoka Peninsula of Sabah state have been described. Early activity of 3-5 parous Ma. bonneae during the first hour after sunset was noted. Age composition of Ma. bonneae at forest shade, indoor and outdoor of house, comparative buffalo vs human bait outdoor in Kampung Pantai showed all round high parous rates ranging from 66.7 to 75.4%. Population 3-parous and older ranged from 18.8 to 26.7%. Nine of the 14 infective Ma. bonneae were 3-parous and this segment of the population was engaged in active transmission. High parous rates were observed in Ma. dives and Ma. uniformis taken in small numbers. Parous rates of Ma. bonneae taken in Kampung Delima and Kampung Taradas were also high. Estimates of daily survivorship of Ma. bonneae and Ma. dives determined by two methods were very high.
    Matched MeSH terms: Insect Vectors/parasitology; Insect Vectors/physiology*
  2. Field studies on the surveillance of Coquillettidia crassipes (Van der Wulp) and the isolation of a strain of Cardiofilaria in peninsular Malaysia
    Chiang GL, Samarawickrema WA, Eng KL, Cheong WH, Sulaiman I, Yap HH
    Ann Trop Med Parasitol, 1986 Apr;80(2):235-44.
    PMID: 2875691
    Surveillance methods for Coquillettidia crassipes were studied in an open housing estate near Kuala Lumpur using three types of traps Trinidad 10 trap, modified Lard can trap and IMR trap, each baited with chicken or pigeon. All traps attracted Cq. crassipes. There was no significant difference in the catches in the three traps. There was also no significant difference between chicken and pigeon as bait. Catches at heights of 1.5, 3, 4.5 and 6 m did not show any significant difference in density. Cq. crassipes was active at night with an early peak during the first hour of the night and a minor peak between 0100 and 0200 hours. The activity of the parous and nulliparous sections of the population was similar, except that a higher proportion of the parous females was active during the second peak compared with the nulliparous females. The parous rate was 22.3%, and the probability of survival through one day for two gonotrophic cycles was 0.711 and 0.650. The infection rate for Cardiofilaria was 29 out of 1052 (2.76%) and the infective rate (L3 larvae) was 13 out of 1052 (1.24%). 48.3% of the infected Cq. crassipes had a worm burden of more than ten larvae. One of the chickens in the traps was positive for microfilariae of Cardiofilaria four weeks after exposure as bait. Laboratory bred Cq. crassipes fed on this chicken produced infective larvae in ten days, and these were inoculated into clean chickens and pigeons. Microfilariae appeared in the chickens but not in pigeons. The adult worms recovered await identification.
    Matched MeSH terms: Insect Vectors/parasitology*
  3. Filariasis in Bengkoka Peninsula, Sabah, Malaysia: vector studies in relation to the transmission of filariasis
    Chiang GL, Cheong WH, Samarawickrema WA, Mak JW, Kan SK
    Southeast Asian J. Trop. Med. Public Health, 1984 Jun;15(2):179-89.
    PMID: 6150551
    Using seven methods of surveillance, 58 species of mosquitoes from nine genera were in Pantai and the two neighbouring villages during two visits in 1982. Ma. bonneae was the most prevalent species attracted to man. In the forest shade Ma. bonneae and Ma. dives showed activity throughout the 24 hours with peak biting during 1900-2100 hours. An. balabacensis exhibited peak activity shortly after midnight. Inside and outside house, Ma. bonneae showed similar activity except that it ceased during the day. Mansonia was only mildly zoophilic. CDC light traps gave poor yields of mosquitoes. Pyrethrum spray catch inside houses early morning did not include any Mansonia. Outdoor day resting catch included Ma. bonneae fed on man. Transmission of Brugia, probably human filariasis, by Ma. bonneae occurred in Pantai and in the two neighbouring villages. One infection in Ma. dives was found in Pantai. The monthly infective biting rate and monthly transmission potential for Ma. bonneae were estimated at the forest shade and outside the house in Pantai.
    Matched MeSH terms: Insect Vectors*
  4. Effectiveness of repellent/insecticidal bars against malaria and filariasis vectors in peninsular Malaysia
    Chiang GL, Tay SL, Eng KL, Chan ST
    Southeast Asian J. Trop. Med. Public Health, 1990 Sep;21(3):412-7.
    PMID: 1981629
    Field tests were conducted to compare the degree of protection from bites of Mansonia species and Anopheles maculatus by applying two repellent/insecticidal bars, MOSBAR and MOSKIL, to exposed arms and legs. Human test subjects were exposed to natural populations of mosquitos for an 8-hour night time period while using the repellent/insecticidal bars. MOSBAR gave good protection against the bites of Mansonia and An. maculatus. MOSKIL was effective against An. maculatus but not against Mansonia. High mortality was observed among the mosquitos collected from human test subjects treated with the repellent/insecticidal bars. Use of MOSBAR in terms of cost-effectiveness and safety by field and health workers entering into malaria and filariasis endemic areas is discussed.
    Matched MeSH terms: Insect Vectors*
  5. Field and laboratory observations on Coquillettidia crassipes in relation to transmission of Brugia malayi in Peninsular Malaysia
    Chiang GL, Samarawickrema WA, Mak JW, Cheong WH, Sulaiman I, Yap HH
    Ann Trop Med Parasitol, 1986 Feb;80(1):117-21.
    PMID: 2873797
    Field observations were made on Coquillettidia crassipes during a study of Mansonia in a swamp forest ecotype in Tanjong Karang. There was an increase in abundance in July consistent with the increase in abundance of Mansonia and an increase in rainfall. The biting cycle showed a dramatic early peak during the period 1900-2000 hours. The probability of daily survival through one day for the first three gonotrophic cycles was 0.770, 0.722 and 0.759. Two of the 54 Cq. crassipes dissected were infective, with two and 25 L3 larvae of Brugia. Both subperiodic B. malayi and B. pahangi developed into L3 larvae in laboratory bred Cq. crassipes. The index of experimental infection was higher for B. pahangi. Mansonia bonneae and Ma. uniformis showed higher indices of experimental infection than Cq. crassipes for subperiodic B. malayi. It is concluded that in an endemic area with a high density of Cq. crassipes it could act as a secondary vector of Brugian filariasis.
    Matched MeSH terms: Insect Vectors
  6. Fulltext Current vector research challenges in the greater Mekong subregion for dengue, Malaria, and Other Vector-Borne Diseases: A report from a multisectoral workshop March 2019
    Christofferson RC, Parker DM, Overgaard HJ, Hii J, Devine G, Wilcox BA, et al.
    PLoS Negl Trop Dis, 2020 Jul;14(7):e0008302.
    PMID: 32730249 DOI: 10.1371/journal.pntd.0008302
    Matched MeSH terms: Insect Vectors*
  7. Beetle-eating: a Malaysia folk medical practice and its public health implications
    Chu GS, Palmieri JR, Sullivan JT
    Trop Geogr Med, 1977 Dec;29(4):422-7.
    PMID: 610028
    A reported practice of live beetle ingestion in Southeast Asia was investigated among urban Chinese in Kuala Lumpur, Malaysia. Results of four casefindings are: (1) this practice may not be confined to West Malaysia, (2) it occurs among Chinese and Malays, (3) the original use of the beetles as an aphrodisiac has been modified to include treatment of a wide variety of ailments and diseases and (4) the practice is relatively uncommon among urban Chinese. It was also found through experimental studies that ingestion of the live beetles (Palembus dermestoides) represented a potential public health hazard in that the beetles were able to serve as a host for the human-infecting tapeworm Hymenolepis diminuta (Sullivan et al., 1977).
    Matched MeSH terms: Insect Vectors*
  8. Differential preferences of oviposition by Aedes mosquitos in man-made containers under field conditions
    Chua KB, Chua IL, Chua IE, Chua KH
    Southeast Asian J. Trop. Med. Public Health, 2004 Sep;35(3):599-607.
    PMID: 15689073
    A study was made of the oviposit behavior of gravid female Aedes mosquitos in man-made habitats under field conditions. The study showed that the gravid female Aedes mosquitos preferred containers with relatively easy access but not too open to external environmental influence. The dark surface of the containers served as the initial and long-range attractant to the breeding sites. Volatile chemicals generated by the decaying vegetation in the container may serve as a close-range attractant. Finally, the water quality and the quantity of 'food' derived from decaying vegetative matter in the water determined the amount of eggs deposited in each container. The study confirmed previous findings that each gravid female Aedes mosquito had the tendency to lay her eggs in more than one container. However, the results of the study suggests that under favorable conditions, each gravid female Aedes mosquito could be encouraged to lay all her eggs in a single breeding site.
    Matched MeSH terms: Insect Vectors*
  9. Fulltext Effect of chemical fogging on immature Aedes mosquitoes in natural field conditions
    Chua KB, Chua IL, Chua IE, Chua KH
    Singapore Med J, 2005 Nov;46(11):639-44.
    PMID: 16228097
    Dengue and dengue haemorrhagic fever are common and serious arboviral diseases endemic in a number of countries situated in both the tropical and subtropical belts.
    Matched MeSH terms: Insect Vectors/growth & development*; Insect Vectors/virology
  10. Plasmodium hylobati: a malaria parasite of the gibbon
    Collins WE, Contacos PG, Garnham PC, Warren M, Skinner JC
    J Parasitol, 1972 Feb;58(1):123-8.
    PMID: 4335047
    Matched MeSH terms: Insect Vectors
  11. Impact of ecological changes on Anopheles vectors of malaria in some countries of Southeast Asia
    De Las Llagas LA
    Southeast Asian J. Trop. Med. Public Health, 1985 Mar;16(1):146-8.
    PMID: 4023808
    Matched MeSH terms: Insect Vectors*
  12. Fulltext Unusual developing sites of dengue vectors and potential epidemiological implications
    Dieng H, Saifur RG, Ahmad AH, Salmah MR, Aziz AT, Satho T, et al.
    Asian Pac J Trop Biomed, 2012 Mar;2(3):228-32.
    PMID: 23569903 DOI: 10.1016/S2221-1691(12)60047-1
    To identify the unusual breeding sites of two dengue vectors, i.e. Aedes albopictus (Ae. albopictus) and Aedes aegypti (Ae. aegypti).
    Matched MeSH terms: Insect Vectors*
  13. Fulltext Indoor-breeding of Aedes albopictus in northern peninsular Malaysia and its potential epidemiological implications
    Dieng H, Saifur RG, Hassan AA, Salmah MR, Boots M, Satho T, et al.
    PLoS One, 2010;5(7):e11790.
    PMID: 20668543 DOI: 10.1371/journal.pone.0011790
    The mosquito Ae. albopictus is usually adapted to the peri-domestic environment and typically breeds outdoors. However, we observed its larvae in most containers within homes in northern peninsular Malaysia. To anticipate the epidemiological implications of this indoor-breeding, we assessed some fitness traits affecting vectorial capacity during colonization process. Specifically, we examined whether Ae. albopictus exhibits increased survival, gonotrophic activity and fecundity due to the potential increase in blood feeding opportunities.
    Matched MeSH terms: Insect Vectors/physiology; Insect Vectors/virology
  14. Exposure of a Dengue Vector to Tea and Its Waste: Survival, Developmental Consequences, and Significance for Pest Management
    Dieng H, Tan Yusop NS, Kamal NN, Ahmad AH, Ghani IA, Abang F, et al.
    J Agric Food Chem, 2016 May 11;64(18):3485-91.
    PMID: 27115536 DOI: 10.1021/acs.jafc.6b01157
    Dengue mosquitoes are evolving into a broader global public health menace, with relentless outbreaks and the rise in number of Zika virus disease cases as reminders of the continued hazard associated with Aedes vectors. The use of chemical insecticides-the principal strategy against mosquito vectors-has been greatly impeded due to the development of insecticide resistance and the shrinking spectrum of effective agents. Therefore, there is a pressing need for new chemistries for vector control. Tea contains hundreds of chemicals, and its waste, which has become a growing global environmental problem, is almost as rich in toxicants as green leaves. This paper presents the toxic and sublethal effects of different crude extracts of tea on Aedes albopictus. The survival rates of larvae exposed to tea extracts, especially fresh tea extract (FTE), were markedly lower than those in the control treatment group. In addition to this immediate toxicity against different developmental stages, the extracts tested caused a broad range of sublethal effects. The developmental time was clearly longer in containers with tea, especially in those with young larvae (YL) and FTE. Among the survivors, pupation success was reduced in containers with tea, which also produced low adult emergence rates with increasing tea concentration. The production of eggs tended to be reduced in females derived from the tea treatment groups. These indirect effects of tea extracts on Ae. albopictus exhibited different patterns according to the exposed larval stage. Taken together, these findings indicate that tea and its waste affect most key components of Ae. albopictus vectorial capacity and may be useful for dengue control. Reusing tea waste in vector control could also be a practical solution to the problems associated with its pollution.
    Matched MeSH terms: Insect Vectors/drug effects*; Insect Vectors/growth & development; Insect Vectors/physiology
  15. Discarded cigarette butts attract females and kill the progeny of Aedes albopictus
    Dieng H, Saifur RG, Ahmad AH, Rawi CS, Boots M, Satho T, et al.
    J Am Mosq Control Assoc, 2011 Sep;27(3):263-71.
    PMID: 22017091
    Discarded cigarette butts (DCB) waste occurs worldwide, pollutes landscapes, is unsightly, and results in added debris removal costs. There is, therefore, a great deal of current interest in making use of DCBs in beneficial ways. Despite evidence that DCBs are harmful to water fleas (Daphnia magna), which breed in aquatic environments as do mosquito larvae, their impact on dengue vectors is unknown. We examined whether Aedes albopictus alters its ovipositional responses, larval eclosion, and development in response to presence of DCBs in its habitats. We found oviposition activity in DCB-treated water similar to that of control water and that ovipositional activity in DCB solutions steadily increased over time as those solutions aged to 10 days. Larval eclosion was initially suppressed on day 1 in DCB solution, but increased thereafter to levels similar to control larval eclosion rates. The DCB-water solutions produced significantly higher mortality in both 1st and 2nd instars over control larvae for several days after initial exposure. Mortality rates decreased sharply 3 to 5 days postexposure as DCBs continued to decompose. We found increased survival rates during late development, but daily input of fresh DCBs prevented most young larvae from completing development. Taken together, these observations suggest that decomposing did not deter gravid Ae. albopictus females from ovipositing in treated containers and that DCB solutions had larvicidal effects on early instars. Our results are discussed in the context of DCB use to control container-breeding Ae. albopictus, a competent dengue vector in Asia and other parts of the world.
    Matched MeSH terms: Insect Vectors
  16. Fulltext Analysis of nuclear and organellar genomes of Plasmodium knowlesi in humans reveals ancient population structure and recent recombination among host-specific subpopulations
    Diez Benavente E, Florez de Sessions P, Moon RW, Holder AA, Blackman MJ, Roper C, et al.
    PLoS Genet, 2017 Sep;13(9):e1007008.
    PMID: 28922357 DOI: 10.1371/journal.pgen.1007008
    The macaque parasite Plasmodium knowlesi is a significant concern in Malaysia where cases of human infection are increasing. Parasites infecting humans originate from genetically distinct subpopulations associated with the long-tailed (Macaca fascicularis (Mf)) or pig-tailed macaques (Macaca nemestrina (Mn)). We used a new high-quality reference genome to re-evaluate previously described subpopulations among human and macaque isolates from Malaysian-Borneo and Peninsular-Malaysia. Nuclear genomes were dimorphic, as expected, but new evidence of chromosomal-segment exchanges between subpopulations was found. A large segment on chromosome 8 originating from the Mn subpopulation and containing genes encoding proteins expressed in mosquito-borne parasite stages, was found in Mf genotypes. By contrast, non-recombining organelle genomes partitioned into 3 deeply branched lineages, unlinked with nuclear genomic dimorphism. Subpopulations which diverged in isolation have re-connected, possibly due to deforestation and disruption of wild macaque habitats. The resulting genomic mosaics reveal traits selected by host-vector-parasite interactions in a setting of ecological transition.
    Matched MeSH terms: Insect Vectors/genetics
  17. Insecticide susceptibility of Phlebotomus argentipes sandflies, vectors of visceral leishmaniasis in India
    Dinesh DS, Hassan F, Kumar V, Kesari S, Topno RK, Yadav RS
    Trop Med Int Health, 2021 07;26(7):823-828.
    PMID: 33733549 DOI: 10.1111/tmi.13576
    OBJECTIVES: Indoor residual spraying (IRS) with insecticides is the main vector control intervention for the elimination of visceral leishmaniasis in India. After a change in IRS policy in 2015 due to widespread resistance of Phlebotomus argentipes to DDT, IRS with DDT was replaced with alpha-cypermethrin IRS in 2016. The objective of the present study was to evaluate the susceptibility of P. argentipes to DDT and its alternatives, namely malathion and pirimiphos-methyl (organophosphates); alpha-cypermethrin, deltamethrin, lambda-cyhalothrin and permethrin (pyrethroids), and bendiocarb and propoxur (carbamates), in support of visceral leishmaniasis elimination in India.

    METHODS: Phlebotomus argentipes sandflies were collected from the visceral-leishmaniasis endemic states of Bihar, Jharkhand and West Bengal. In the WHO tube tests, the phenotypic susceptibility of F1, 2-day old, non-blood fed females were determined against filter papers impregnated with DDT 4%, malathion 5%, pirimiphos-methyl 0.25%, alpha-cypermethrin 0.05%, deltamethrin 0.05%, lambda-cyhalothrin 0.05%, permethrin 0.75%, bendiocarb 0.1% and propoxur 0.1%, which were sourced from Universiti Sains Malaysia. The knockdown of sandflies after 1-h exposure and mortality at 24 h after the 1-h exposure period were scored.

    RESULTS: Mean mortality of P. argentipes 24 h after exposure in tube tests was 22.6% for DDT and ≥ 98% for other insecticide-impregnated papers tested.

    CONCLUSION: Phlebotomus argentipes continues to be highly resistant to DDT with no reversal of resistance after DDT's withdrawal from IRS. P. argentipes was fully susceptible to pyrethroid, organophosphate and carbamate insecticides tested. Regular monitoring is warranted for insecticide resistance management in sandfly vectors.

    Matched MeSH terms: Insect Vectors/drug effects*
  18. Knowledge, attitudes, and practices related to control of Dengue haemorrhagic fever in an urban Malay kampung
    Dobbins JG, Else JG
    Southeast Asian J. Trop. Med. Public Health, 1975 Mar;6(1):120-6.
    PMID: 1170643
    Matched MeSH terms: Insect Vectors
  19. Measurement of dengue epidemic spreading pattern using density analysis method: retrospective spatial statistical study of dengue in Subang Jaya, Malaysia, 2006-2010
    Dom NC, Ahmad AH, Latif ZA, Ismail R
    Trans R Soc Trop Med Hyg, 2013 Nov;107(11):715-22.
    PMID: 24062522 DOI: 10.1093/trstmh/trt073
    Dengue has emerged as one of the major public health problems in Malaysia. The Ministry of Health, Malaysia, is committed in monitoring and controlling this disease for many years. The objective of this study is to analyze the dengue outbreak pattern on a monthly basis in Subang Jaya in terms of their spatial dissemination and hotspot identification.
    Matched MeSH terms: Insect Vectors/virology*
  20. Molecular evidence of speciation between island and continental populations of Anopheles (Cellia) sundaicus (Diptera: Culicidae), a principal malaria vector taxon in Southeast Asia
    Dusfour I, Linton YM, Cohuet A, Harbach RE, Baimai V, Trung HD, et al.
    J Med Entomol, 2004 May;41(3):287-95.
    PMID: 15185927
    Anopheles sundaicus s.l. is a principal malaria vector taxon on islands and along the coastal areas of Southeast Asia. It has a wide geographical distribution and exhibits a high level of ecological and behavioral variability. Study of this taxon is crucial for understanding its biology and implementing effectise vector control measures. We compared populations of An. sundaicus from Vietnam, Thailand, and Malaysian Borneo by using two mitochondrial DNA markers: cytochrome oxidase I and cytochrome b. Genetic divergence, geographic separation, and cladistic analysis of relationships revealed the presence of two cryptic species: Anopheles sundaicus s.s. on Malaysian Borneo and An. sundaicus species A in coastal areas of Thailand and Vietnam. A polymerase chain reaction (PCR) assay was developed to easily identify these two species throughout their geographic distributions. The assay was based on sequence characterized amplified region derived from random amplified polymorphic DNA. This PCR identification method needs to be validated and adapted for the recognition of other possible species in the Sundaicus Complex.
    Matched MeSH terms: Insect Vectors
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