Displaying publications 1 - 20 of 28 in total

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  1. Zoonotic Brugia pahangi filariasis in a suburbia of Kuala Lumpur City, Malaysia
    Tan LH, Fong MY, Mahmud R, Muslim A, Lau YL, Kamarulzaman A
    Parasitol Int, 2011 Jan;60(1):111-3.
    PMID: 20951228 DOI: 10.1016/j.parint.2010.09.010
    Five local Malaysian patients with clinical manifestations consistent with lymphatic filariasis were referred to our medical centre between 2003 and 2006. Although no microfilariae (mf) were detected in their nocturnal blood samples, all were diagnosed to have lymphatic filariasis on the basis of clinical findings and positive serology results. PCR on their blood samples revealed that two of the patients were infected with Brugia pahangi, an animal filarial worm hitherto not known to cause human disease in the natural environment. All the patients were successfully treated with anti-filarial drugs: four patients were treated with a combination of diethylcarbamazine (DEC) and albendazole, and one with doxycycline. Four of them were residents of Petaling Jaya, a residential suburbia located 10 km southwest of Kuala Lumpur city, Malaysia. The fifth patient was a frequent visitor of the suburbia. This suburbia has no history or record of B. malayi infection. The most likely vector of the worm was Armigeres subalbatus as extensive entomological surveys within the suburbia revealed only adult females of this mosquito species were infected with B. pahangi larvae. Wild monkeys caught in the suburbia were free from B. pahangi mf, but domestic cats were mf positive. This suggests that infected cats might be the source of the zoonotic infection in the suburbia.
    Matched MeSH terms: Culicidae/parasitology
  2. Fulltext Vector and reservoir host of a case of human Brugia pahangi infection in Selangor, peninsular Malaysia
    Muslim A, Fong MY, Mahmud R, Sivanandam S
    Trop Biomed, 2013 Dec;30(4):727-30.
    PMID: 24522144 MyJurnal
    A case of human eye infection caused by Brugia pahangi was reported in 2010 in a semi rural village in Selangor, peninsular Malaysia. Our report here reveals results of investigation on the vector and animal host for the transmission of the infection. We conducted entomological survey and cat blood examination in the vicinity of the patient's home. The mosquito species Armigeres subalbatus was incriminated as the vector, whereas cat served as the reservoir host.
    Matched MeSH terms: Culicidae/parasitology*
  3. Update on the bionomics of Mansonia vectors of brugian filariasis
    Chiang GL
    Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:69-75.
    PMID: 7973951
    The genus Mansonia is divided into two subgenera, Mansonia and Mansonioides. The subgenus Mansonioides includes the important vectors of lymphatic filariasis caused by Brugia malayi in South and Southeast Asia. Six species of this subgenus are vectors of two types of brugian filariasis, periodic and subperiodic. All six species, viz Mansonia bonneae, Ma. dives, Ma. uniformis, Ma. annulifera, Ma. annulata and Ma. indiana are present in this country. The ecological factors governing the larval and adult biology and their control measures are discussed.
    Matched MeSH terms: Culicidae/parasitology
  4. The fate of Brugia pahangi microfilariae in Armigeres subalbatus during the first 48 hours post ingestion
    Zahedi M
    Trop. Med. Parasitol., 1994 Mar;45(1):33-5.
    PMID: 7915044
    In Armigeres subalbatus, 60% and 3% of the ingested Brugia pahangi microfilariae (mf) respectively migrated into the haemocoel and the thorax within 5 minutes post ingestion (p.i.). Most of the mf had migrated from the gut into the haemocoel within the first 10 minutes p.i. There was no correlation between the number of mf ingested and the migration rate though those in mosquitoes with a low mf burden tend to migrate earlier. At 24 hours p.i., 5-30% of the mf were still in the gut; 19% of these mf were immobile. At 48 hours p.i. only 2% of the mf were mobile. B. pahangi mf isolated from blood meals at 24 hours p.i., failed to develop when inoculated into Armigeres subalbatus. 54% and 73% of the mf isolated from a 24 hour old clotted blood of a B. pahangi-infected cat and fresh peripheral cat blood respectively developed into stage-1 larva. Probably mf left in the midgut at 24 hours p.i. are the young and immature worms and are physiologically incapable of penetrating the gut.
    Matched MeSH terms: Culicidae/parasitology*
  5. Fulltext The Plasmodium falciparum male gametocyte protein P230p, a paralog of P230, is vital for ookinete formation and mosquito transmission
    Marin-Mogollon C, van de Vegte-Bolmer M, van Gemert GJ, van Pul FJA, Ramesar J, Othman AS, et al.
    Sci Rep, 2018 10 08;8(1):14902.
    PMID: 30297725 DOI: 10.1038/s41598-018-33236-x
    Two members of 6-cysteine (6-cys) protein family, P48/45 and P230, are important for gamete fertility in rodent and human malaria parasites and are leading transmission blocking vaccine antigens. Rodent and human parasites encode a paralog of P230, called P230p. While P230 is expressed in male and female parasites, P230p is expressed only in male gametocytes and gametes. In rodent malaria parasites this protein is dispensable throughout the complete life-cycle; however, its function in P. falciparum is unknown. Using CRISPR/Cas9 methodology we disrupted the gene encoding Pfp230p resulting in P. falciparum mutants (PfΔp230p) lacking P230p expression. The PfΔp230p mutants produced normal numbers of male and female gametocytes, which retained expression of P48/45 and P230. Upon activation male PfΔp230p gametocytes undergo exflagellation and form male gametes. However, male gametes are unable to attach to red blood cells resulting in the absence of characteristic exflagellation centres in vitro. In the absence of P230p, zygote formation as well as oocyst and sporozoite development were strongly reduced (>98%) in mosquitoes. These observations demonstrate that P230p, like P230 and P48/45, has a vital role in P. falciparum male fertility and zygote formation and warrants further investigation as a potential transmission blocking vaccine candidate.
    Matched MeSH terms: Culicidae/parasitology*
  6. Studies of Coquillettidia (coquillettidia) crassipes (Vanderwulp, 1881) in relation to transmission of Cardiofilaria nilesi
    Klinkaewnarong W, Chiang GL, Eng KL
    Southeast Asian J. Trop. Med. Public Health, 1985 Mar;16(1):10-4.
    PMID: 2862708
    Field surveillance of Cq. crassipes was conducted in an open housing estate near Kuala Lumpur using IMR traps baited with chicken and gerbils. Chicken bait attracted more Cq. crassipes. There was significant difference between chicken and gerbil as bait. The mosquitoes preferred to feed at canopy level. The parous rate was 20.41% and the infection rate for Cardiofilaria nilesi was 2.04%. None of the 120 chicken and 5 ducks, in a village close to the open housing estate, examined for microfilariae were positive. Ar. durhami and Ar. subalbatus did not support development of C. nilesi. However, Cq. crassipes is an extremely efficient vector of C. nilesi.
    Matched MeSH terms: Culicidae/parasitology*
  7. Recent pathogen and mosquito host records from Penang Island, Malaysia
    Chapman HC, Lacey LA, Yap HH
    J Am Mosq Control Assoc, 1987 Jun;3(2):306-8.
    PMID: 2904951
    Matched MeSH terms: Culicidae/parasitology*
  8. Fulltext Predicting the geographical distributions of the macaque hosts and mosquito vectors of Plasmodium knowlesi malaria in forested and non-forested areas
    Moyes CL, Shearer FM, Huang Z, Wiebe A, Gibson HS, Nijman V, et al.
    Parasit Vectors, 2016 Apr 28;9:242.
    PMID: 27125995 DOI: 10.1186/s13071-016-1527-0
    BACKGROUND: Plasmodium knowlesi is a zoonotic pathogen, transmitted among macaques and to humans by anopheline mosquitoes. Information on P. knowlesi malaria is lacking in most regions so the first step to understand the geographical distribution of disease risk is to define the distributions of the reservoir and vector species.

    METHODS: We used macaque and mosquito species presence data, background data that captured sampling bias in the presence data, a boosted regression tree model and environmental datasets, including annual data for land classes, to predict the distributions of each vector and host species. We then compared the predicted distribution of each species with cover of each land class.

    RESULTS: Fine-scale distribution maps were generated for three macaque host species (Macaca fascicularis, M. nemestrina and M. leonina) and two mosquito vector complexes (the Dirus Complex and the Leucosphyrus Complex). The Leucosphyrus Complex was predicted to occur in areas with disturbed, but not intact, forest cover (> 60% tree cover) whereas the Dirus Complex was predicted to occur in areas with 10-100% tree cover as well as vegetation mosaics and cropland. Of the macaque species, M. nemestrina was mainly predicted to occur in forested areas whereas M. fascicularis was predicted to occur in vegetation mosaics, cropland, wetland and urban areas in addition to forested areas.

    CONCLUSIONS: The predicted M. fascicularis distribution encompassed a wide range of habitats where humans are found. This is of most significance in the northern part of its range where members of the Dirus Complex are the main P. knowlesi vectors because these mosquitoes were also predicted to occur in a wider range of habitats. Our results support the hypothesis that conversion of intact forest into disturbed forest (for example plantations or timber concessions), or the creation of vegetation mosaics, will increase the probability that members of the Leucosphyrus Complex occur at these locations, as well as bringing humans into these areas. An explicit analysis of disease risk itself using infection data is required to explore this further. The species distributions generated here can now be included in future analyses of P. knowlesi infection risk.

    Matched MeSH terms: Culicidae/parasitology
  9. Parasitological and entomological studies on filariasis in seven villages, Serian District, Sarawak, East Malaysia
    Rubis P, Chang MS, Nagum AJ, Jau JL
    Southeast Asian J. Trop. Med. Public Health, 1981 Mar;12(1):30-5.
    PMID: 6114566
    A total of 82 persons have been found to be positive for microfilaria a sub-periodic Brugia malayi out of 1,613 examined in seven villages in Serian District. This represents an average microfilaria infection rate of 5.1% with a range of zero to 10.7%. It is found that males are more predominantly affected than females with a ratio of 3:1. It is also confirmed that Mansonia dives and M. bonneae are possible vectors for the transmission of the disease although Anopheles species cannot be ruled out owing to the small number of specimens examined. The study is confined to areas where indoor DDT spraying has been done since 1960 and only in two of the areas it has been terminated in 1966. Yet to be published data shows higher filaria infection rate than any of these villages.
    Matched MeSH terms: Culicidae/parasitology*
  10. Operational issues in the control of the vectors of Brugia
    Chang MS
    Ann Trop Med Parasitol, 2002 Dec;96 Suppl 2:S71-6.
    PMID: 12625920
    An estimated 13 million people in the Oriental Region have brugian filariasis. The filarial parasites that cause this disease exist in periodic and sub-periodic forms and are transmitted by four genera of mosquito: Anopheles, Mansonia and, less frequently, Coquillettidia and Ochlerotatus. In most endemic countries, control of the disease has been entirely based on chemotherapy, although house-spraying and use of insecticide-treated bednets can be quite effective against the vectors of nocturnally periodic Brugia malayi and B. timori. The vector-control methods that may be applied against the Mansonia mosquitoes that transmit the parasites causing sub-periodic brugian filariasis are reviewed here. Most of the conventional methods for controlling the immature, aquatic stages of mosquitoes have proved unsatisfactory against Mansonia. The reason is that, unlike the those of other genera, the larvae and pupae of Mansonia spp. are relatively immobile and obtain air not at the water surface but from the underwater roots, stems and leaves of floating plants to which the larvae and pupae attach. Removal of host plants can be very effective in reducing Mansonia productivity, whereas large-scale use of herbicides is restricted by the potential adverse effects on the ecosystem. Environmental management in water-development projects remains the best option.
    Matched MeSH terms: Culicidae/parasitology*
  11. Fulltext Lymphatic filariasis in Peninsular Malaysia: a cross-sectional survey of the knowledge, attitudes, and practices of residents
    Al-Abd NM, Nor ZM, Ahmed A, Al-Adhroey AH, Mansor M, Kassim M
    Parasit Vectors, 2014;7:545.
    PMID: 25428558 DOI: 10.1186/s13071-014-0545-z
    Lymphatic filariasis (LF) is a major cause of permanent disability in many tropical and sub-tropical countries of the world. Malaysia is one of the countries in which LF is an endemic disease. Five rounds of the mass drug administration (MDA) program have been conducted in Malaysia as part of the Global Program to Eliminate Lymphatic Filariasis (GPELF) by year 2020. This study investigated the level of awareness of LF and the MDA program in a population living in an endemic area of the country.
    Matched MeSH terms: Culicidae/parasitology
  12. Lankesteria, a gregarine protozoan, previously unreported in mosquitoes of Malaysia
    Else JG, Dangsupa P
    Southeast Asian J. Trop. Med. Public Health, 1974 Sep;5(3):454.
    PMID: 4154508
    Matched MeSH terms: Culicidae/parasitology*
  13. Genetic aspects of lymphatic filariasis
    Yong HS, Mak JW
    Southeast Asian J. Trop. Med. Public Health, 1993;24 Suppl 2:37-9.
    PMID: 7973944
    The genetics of human susceptibility to lymphatic filariasis, the genetic basis of filarial susceptibility in vector mosquitos, and the genetic constitution of human filarial parasites and their mosquito vectors are reviewed. It is evident that our present knowledge on the genetics of lymphatic filariasis is still very meagre. The need to study various genetic aspects of the disease is highlighted.
    Matched MeSH terms: Culicidae/parasitology
  14. Fulltext First report of mermithid parasitism (Nematoda: Mermithidae) in mosquitoes (Diptera: Culicidae) from Lao PDR
    Vythilingam I, Sidavong B, Seng TC, Phonemixay T, Phompida S, Krishnasamy M
    Trop Biomed, 2005 Jun;22(1):77-9.
    PMID: 16880758
    Unidentified mermithid nematodes were found in the abdominal cavity of three species of Anopheles mosquitoes from LAO PDR. This is a first record of mermithid nematodes in adult mosquitoes from Lao PDR. Two worms were found in each adult host and the infection was more prevalent in the northern region compared to the south.
    Matched MeSH terms: Culicidae/parasitology*
  15. 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: Culicidae/parasitology
  16. 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: Culicidae/parasitology*
  17. 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: Culicidae/parasitology*
  18. Environmental variables associated with immature stage habitats of culicidae collected in aboriginal villages in Pahang, Malaysia
    Ali WN, Ahmad R, Nor ZM, Ismail Z, Ibrahim MN, Hadi AA, et al.
    Southeast Asian J. Trop. Med. Public Health, 2012 Nov;43(6):1387-99.
    PMID: 23413702
    Many of the most widely spread vector-borne diseases are water related, in that the mosquito vectors concerned breed or pass part of their lifecycle in or close to water. A major reason for the study of mosquito larval ecology is to gather information on environmental variables that may determine the species of mosquitoes and the distribution of larvae in the breeding habitats. Larval surveillance studies were conducted six times between May 2008 and October 2009 in Pos Lenjang, Kuala Lipis, Pahang. Twelve environmental variables were recorded for each sampling site, and samples of mosquito larvae were collected. Larval survey studies showed that anopheline and culicine larvae were collected from 79 and 67 breeding sites, respectively. All breeding sites were classified into nine habitat groups. Culicine larvae were found in all habitat groups, suggesting that they are very versatile and highly adaptable to different types of environment. Rock pools or water pockets with clear water formed on the bank of rivers and waterfalls were the most common habitats associated with An. maculatus. Environmental variables influence the suitability of aquatic habitats for anopheline and culicine larvae, but not significantly associated with the occurrence of both larvae genera (p>0.05). This study provides information on mosquito ecology in relation to breeding habitats that will be useful in designing and implementing larval control operations.
    Matched MeSH terms: Culicidae/parasitology
  19. Efficacy of diethylcarbamazine and pirimiphos-methyl residual spraying in controlling brugian filariasis
    Chang MS, Ho BC, Chan KL
    Trop. Med. Parasitol., 1991 Jun;42(2):95-102.
    PMID: 1680246
    A control programme against subperiodic brugian filariasis was implemented in three villages, (Kg. Ampungan, Kg. Sebangkoi and Kg. Sebamban) in Sarawak, Malaysia. In Kampong Ampungan, the mass administration of diethylcarbamazine (DEC-citrate) combined with residual house spraying of pirimiphos-methyl reduced microfilarial rate to 8% of the pre-treatment level and microfilarial density (MfD50) to 44% of the pre-treatment level over a period of four years. In Kampong Sebangkoi and Kampong Sebamban, where only mass DEC therapy was applied, the microfilarial rate and MfD50 declined distinctly in the second blood survey but increased gradually in two subsequent follow-up blood surveys. In Kg, Ampungan, we observed a significant reduction of infective biting rate (88.3%), infection rate (62.5%) and transmission potential (88.1%) of Mansonia bonneae at the fourth spray round. The corresponding reduction rates in Kg. Sebangkoi and Kg. Sebamban were 35.3%, 26.7%, 42.2% and 24%, 30.8% and 15.4% respectively. The biting density of the vector was reduced by 79.8% indoors and 31.8% outdoors at the sprayed village, while only a slight decrease in densities (17.9% indoors and 12.4% outdoors) was observed at the unsprayed village. Bioassay tests revealed that pirimiphos-methyl had a substantial fumigant effect on the vector. The integrated control measure in controlling subperiodic brugian filariasis is discussed.
    Matched MeSH terms: Culicidae/parasitology
  20. Efficacy of Clostridium bifermentans serovar Malaysia on target and nontarget organisms
    Yiallouros M, Storch V, Thiery I, Becker N
    J Am Mosq Control Assoc, 1994 Mar;10(1):51-5.
    PMID: 7912261
    Clostridium bifermentans serovar malaysia (C.b.m.) is highly toxic to mosquito larvae. In this study, the following aquatic nontarget invertebrates were treated with high C.b.m. concentrations (up to 1,600-fold the toxic concentration for Anopheles stephensi) to study their susceptibility towards the bacterial toxin: Planorbis planorbis (Pulmonata); Asellus aquaticus (Isopoda); Daphnia pulex (Cladocera); Cloeon dipterum (Ephemeroptera); Plea leachi (Heteroptera); and Eristalis sp., Chaoborus crystallinus, Chironomus thummi, and Psychoda alternata (Diptera). In addition, bioassays were performed with mosquito larvae (Aedes aegypti, Anopheles stephensi, and Culex pipiens). Psychoda alternata larvae were very susceptible, with LC50/LC90 values comparable to those of mosquito larvae (about 10(3)-10(5) spores/ml). The tests with Chaoborus crystallinus larvae showed significant mortality rates at high concentrations, but generally not before 4 or 5 days after treatment. The remaining nontarget organisms did not show any susceptibility. The investigation confirms the specificity of C.b.m. to nematocerous Diptera.
    Matched MeSH terms: Culicidae/parasitology*
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