Displaying publications 1 - 20 of 656 in total

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  1. Nicolas L, Charles JF, de Barjac H
    FEMS Microbiol Lett, 1993 Oct 01;113(1):23-8.
    PMID: 8243978
    The toxicity of Clostridium bifermentans serovar malaysia to mosquito larvae is due to protein toxins, belonging to a novel class of insecticidal toxins. Toxic extracts contains three major proteins of 66, 18 and 16 kDa. The 18-kDa and 16-kDa proteins are probably involved in toxicity. They are synthesised during sporulation, concomitant with activity. They are absent from non-toxic strains of C. bifermentans and are present at very low levels in non-toxic C. bifermentans serovar malaysia cultures produced at 42 degrees C. The 66-kDa protein is present throughout the growth phases of C. bifermentans serovar malaysia, and an immunologically related 66-kDa protein is present in non-toxic C. bifermentans strains.
    Matched MeSH terms: Larva/drug effects
  2. Ng, Amelia Phei Fang, Teh, Chiew Peng, Poi, Khoy Yen, Tan, Aileen Shau Hwai, Zulfigar Yasin
    Trop Life Sci Res, 2016;27(11):23-29.
    MyJurnal
    The effects of salinity on the embryonic and larvae stage of Crassostrea iredalei
    were investigated. Fertilised eggs and one day old D-larvae were subjected to salinities
    ranging from 0 to 30 ppt at temperature of 30±2°C. At salinity lower than 10 ppt, 100%
    mortality was observed. For embryo development, the highest survival was observed at
    salinity 25 ppt with 80.9±2.2% survival with no significant difference compared to 15 and
    30 ppt. Shell height and length were both greatest at salinity 30 ppt. Throughout the 11
    days culture, the highest larval survival occurred at salinity 15 ppt with no significant
    difference compared to all other salinities except 10 ppt. Larval shell sizes showed no
    significant differences between salinities, except for 10 ppt. Optimum culture condition for
    larvae growth are salinities ranging from 15 to 30 ppt whereby the larval of this species
    can tolerate wider range of salinity compared to other oyster species and thus, making it a
    competitive species to be cultured.
    Matched MeSH terms: Larva
  3. Mohamad N, Zuharah WF
    Trop Biomed, 2014 Mar;31(1):166-73.
    PMID: 24862057 MyJurnal
    Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia.
    Matched MeSH terms: Larva
  4. Norsarwany M, Abdelrahman Z, Rahmah N, Ariffin N, Norsyahida A, Madihah B, et al.
    Trop Biomed, 2012 Sep;29(3):479-88.
    PMID: 23018511
    Strongyloidiasis is an infection caused by the intestinal nematode Strongyloides stercoralis. Infected healthy individuals are usually asymptomatic, however it is potentially fatal in immunocompromised hosts due to its capacity to cause an overwhelming hyperinfection. Strongyloidiasis could be missed during routine screening because of low and intermittent larval output in stool and variable manifestations of the symptoms. We present two cases of strongyloidiasis occurring in children with solid organ malignancies suspected to have the infection based on their clinical conditions and treatment history for cancer. Both patients were diagnosed by molecular and serological tests and were successfully treated. Thus, strongyloidiasis in patients undergoing intensive treatment for malignancies should be suspected, properly investigated and treated accordingly.
    Matched MeSH terms: Larva
  5. Akbar John B, Kamaruzzaman B, Jalal K, Zaleha K
    Sains Malaysiana, 2012;41:855-861.
    The first time report on the feeding ecology and food preference of mangrove horseshoe crab Carcinoscorpius rotundicauda (Latreille 1802) at their nesting grounds along the Pahang coast is given. Monthly sampling was carried out between March 2010 and February 2011 covering both monsoonal (March to October) and non-monsoonal (November to February) seasons. Major macrobenthic gut contents (bivalves, gastropods, crustaceans, polychaetes and miscellaneous food items including plant materials) were identified using microscopic examination. An electivity index (E1) was calculated for the frequent food items observed in the gut region of C. rotundicauda during monsoon and non-monsoon seasons. The EI was negative for crustaceans and positive for all the other food items including bivalves, gastropods, polychaetes and miscellaneous food items (which include insects, amphipods, Isopods, larval and juvenile stages of fishes, foraminifera and other Annelid worms). It is interesting to note that C. rotundicauda prefered less number of bivalves than polychaetes during non monsoon seasons but it was the reverse during monsoonal period. Male crabs intensely preyed on gastropods and female prefers polychaete worms during the peak mating/nesting season (June - August 2010). Seasonal variations in food composition showed that mollusks formed the main item especially gastropods. Unidentified organic matters in the gut content analysis of C. rotundicauda showed high preference towards plant materials. Gastro Somatic Index (GaSI) analysis showed that the feeding intensity of male crabs was higher during non-monsoon period while it was higher during monsoonal period in female crabs. In conclusion, the feeding ecology of mangrove horseshoe crabs were more similar to its closer and distant conspecifics. However, it was postulated that the higher preference of polychaete worms by the female C. rotundicauda during the peak mating season indicated its role in regulating the nesting behaviour.
    Matched MeSH terms: Larva
  6. Chan HH, Zairi J
    J Med Entomol, 2013 Mar;50(2):362-70.
    PMID: 23540125
    Insecticide resistance has become a serious issue in vector management programs. Information on insecticidal resistance and its associated mechanisms is important for successful insecticide resistance management. The selection of a colony of permethrin-resistant Aedes albopictus (Skuse) (Diptera: Culicidae), originating from Penang Island, Malaysia, yielded high larval-specific resistance to permethrin and cross-resistance to deltamethrin. Synergism assays showed that the major mechanism underlying this resistance involves cytochrome P450 monooxygenase. The resistance is autosomal, polygenically inherited and incompletely dominant (D = 0.26). Resistant larvae were reared under different conditions to assess the fitness costs. Under high larval density, larval development time of the resistant SGI strain was significantly longer than the susceptible VCRU strain. In both high- and low-density conditions SGI showed a lower rate of emergence and survival compared with the VCRU strain. Resistant larvae were more susceptible to predation by Toxorhynchites splendens (Wiedemann) (Diptera: Culicidae) larvae. The body size of SGI females reared under high-density conditions was larger compared with females of the susceptible strain. SGI females survived longer when starved than did VCRU females. The energy reserve upon eclosion was positively correlated with the size of the adults.
    Matched MeSH terms: Larva/drug effects; Larva/genetics
  7. Yap HH, Lee YW, Zairi J
    J Am Mosq Control Assoc, 2002 Mar;18(1):52-6.
    PMID: 11998931
    Bioefficacy of thermal fogging application of 2 Bacillus thuringiensis israelensis formulations, Vectobac ABG 6511 water-dispersible granules (3,000 international toxic unit [ITU]/mg) and Vectobac 12AS liquid (1,200 ITU/mg), was assessed for larvicidal activities against Aedes aegypti, Aedes albopictus, Anopheles dirus, and Culex quinquefasciatus. Portable Agrofog AF35 sprayers were used to apply the 2 formulations indoors in residential premises on Penang Island, Malaysia. Vectobac ABG 6511 showed good larvicidal effect against all 4 mosquito species at 3 of the higher doses tested (2.91 x 10(9), 1.45 x 10(9), and 0.71 x 10(9) ITU/ha), with more than 96% mortality at 48 h after spraying. As a comparative formulation, Vectobac 12AS also showed good larvicidal activity against all 4 mosquito species at 2 of the higher doses tested (2.87 x 10(9) and 1.46 x 10(9) ITU/ha), with more than 92.5% mortality at 48 h after spraying. Larvae of An. dirus were significantly more susceptible to both water-based Vectobac formulations when compared to the other 3 mosquito species. Both microbial formulations showed better efficacy at higher doses. However, even at the lowest dose tested, Vectobac ABG 6511 and Vectobac 12AS (both at 0.36 x 10(9) ITU/ha) showed larvicidal properties, with more than 66% mortality at 48 h after spraying. Overall, for this bacterial agent, the water-dispersible granule formulation has better prospects than the liquid formulation for the control of larvae of vector mosquitoes.
    Matched MeSH terms: Larva
  8. Lee YW, Zairi J
    Trop Biomed, 2006 Jun;23(1):37-44.
    PMID: 17041550 MyJurnal
    Studies were carried out on the residual efficacy of Bacillus thuringiensis H-14 (water dispersible granule, VectoBac ABG 6511) as direct application in the control of Aedes larvae in the field. Field Aedes sp populations in the earthen and glass jars were predetermined before initiation of the trial. On confirmation of the presence of Aedes species in the designated area, Sungai Nibong Kecil, Penang Island, Malaysia, Bti was introduced in the 55L earthen and 3L glass jars). Two test designs were carried out. The first design had treated water replenished daily with 6L of seasoned water and the second design is without the replenishment of water but evaporated water was replenished. Bti was effective in the field for at least 35 days with more than 80% reduction in the Aedes larvae in the treated containers. For earthen jars with daily replenishment of water, 100% reduction was recorded for the first 3 days, while more than 80% reduction was recorded up to day 40. At day 60, Bti still provided an efficacy of 54.32 +/- 4.61 (%) of reduction. Whilst for earthen jars without daily replenishment of water, 100% reduction was recorded for the first 5 days, while more than 80% of reduction was recorded up to day 40. For the glass jars studied, similar efficacy was observed. In jars with daily replenishment of water a better larval control was observed. Percentage of reduction from day 50 to 60 for replenishment of water was between 50 to 70% compared to without replenishment of water with less than 40%.
    Matched MeSH terms: Larva
  9. Ariff N, Abdullah A, Azmai MNA, Musa N, Zainathan SC
    Vet World, 2019 Aug;12(8):1273-1284.
    PMID: 31641308 DOI: 10.14202/vetworld.2019.1273-1284
    Background and Aim: Viral nervous necrosis (VNN) is a serious disease of several marine fish species. VNN causes 100% mortality in the larval stages, while lower losses have been reported in juvenile and adult fish. This study aimed to detect the occurrence of VNN while identifying its associated risk factors and the genotypes of its causative agent in a hybrid grouper hatchery in Malaysia.

    Materials and Methods: A batch of newly hatched hybrid grouper fry (Epinephelus fuscoguttatus × Epinephelus lanceolatus) were followed from the larval stage to market size. Samples of the hybrid groupers, water, live feed, and artificial fish pellets were collected periodically from day 0 to 180 in the hybrid grouper hatchery. Reverse transcription-polymerase chain reaction (RT-PCR) and nested PCR amplifications were carried out on VNN-related sequences. The phylogenetic tree including the sampled causative agent of VNN was inferred from the coat protein genes from all known Betanodavirus species using Molecular Evolutionary Genetics Analysis (MEGA). Pearson's correlation coefficient values were calculated to determine the strength of the correlation between the presence of VNN in hybrid grouper samples and its associated risk factors.

    Results: A total of 113 out of 146 pooled and individual samples, including hybrid grouper, water, and artificial fish pellet samples, demonstrated positive results in tests for the presence of VNN-associated viruses. The clinical signs of infection observed in the samples included darkened skin, deformation of the backbone, abdominal distension, skin lesions, and fin erosion. VNN was present throughout the life stages of the hybrid groupers, with the first detection occurring at day 10. VNN-associated risk factors included water temperature, dissolved oxygen content, salinity, ammonia level, fish size (adults more at risk than younger stages), and life stage (age). Detection of VNN-associated viruses in water samples demonstrated evidence of horizontal transmission of the disease. All the nucleotide sequences found in this study had high nucleotide identities of 88% to 100% to each other, striped jack nervous necrosis virus (SJNNV), and the reassortant strain red-spotted grouper NNV/SJNNV (RGNNV/SJNNV) isolate 430.2004 (GenBank accession number JN189932.1) (n=26). The phylogenetic analysis showed that quasispecies was present in each VNN-causing virus-positive sample, which differed based on the type of sample and life stage.

    Conclusion: This study was the first to confirm the existence of a reassortant strain (RGNNV/SJNNV) in hybrid groupers from Malaysia and Southeast Asia. However, the association between the mode of transmission and the risk factors of this virus needs to be investigated further to understand the evolution and potential new host species of the reassortant strain.

    Matched MeSH terms: Larva
  10. Takaoka H, Sofian-Azirun M, Ya'cob Z, Chen CD, Low VL, Zaid A
    J Med Entomol, 2016 Jan;53(1):76-82.
    PMID: 26516192 DOI: 10.1093/jme/tjv154
    Simulium (Gomphostilbia) merapiense sp. nov. is described based on females, males, pupae, and mature larvae from Yagyakarta, Java, Indonesia. This new species is placed in the Simulium epistum species-group, and is characterized by the pupal gill with eight short filaments all arising at the same level from a short stalk, somewhat enlarged basal fenestra, entirely bare pupal head and thoracic integument, and small and short larval postgenal cleft. These characters rarely are found in the subgenus. Taxonomic notes are given to separate this new species from related species of the S. epistum species-group.
    Matched MeSH terms: Larva/anatomy & histology
  11. Chandrawathani P, Jamnah O, Waller PJ, Larsen M, Gillespie AT, Zahari WM
    Vet Parasitol, 2003 Nov 14;117(3):173-83.
    PMID: 14630426
    Control of nematode parasites of small ruminants in a wet, tropical environment using the nematophagous fungus, Duddingtonia flagrans, was assessed in this study. Two methods of fungal delivery were tested, namely as a daily feed supplement, or incorporated into feed blocks. Initially, pen trials were conducted with individually penned groups of sheep and goats at dose rates of 125,000 spores and 250,000 spores/kg live weight per day. At the lower dose rate this reduction was between 80 and 90% compared with the pre-treatment levels. At the higher dose rate, there was virtually complete suppression (>99% reduction) of larval recovery. Trials using the fungal feed blocks, showed that when animals were individually penned, they consumed only small amounts of the block (particularly goats), hence little effect on larval recovery in faecal cultures was observed. Grouping animals according to species and dose rate induced satisfactory block consumption and subsequent high levels of larval reduction in faecal cultures. These larval reductions were mirrored by the presence of fungus in faecal cultures. This work was followed by a small paddock trial, whereby three groups of sheep were fed either a feed supplement without fungal spores, supplement with spores, or offered fungal blocks. The dose rate of spores in the latter two groups was 500,000 spores/kg live weight per day. Egg counts were significantly reduced in the two fungal groups, compared with the control group and the latter required two salvage anthelmintic treatments to prevent mortality due to haemonchosis. Pasture larval numbers on the two fungal group plots were also much lower than on the control plot.
    Matched MeSH terms: Larva
  12. Mahat NA, Jayaprakash PT, Zafarina Z
    Trop Biomed, 2012 Mar;29(1):9-17.
    PMID: 22543598 MyJurnal
    The use of Chrysomya megacephala larvae for detecting malathion for diagnosing the cause of death was investigated. This could prove useful when the visceral organs have become liquefied during decomposition and therefore cannot be sampled. A field experiment was conducted in which C. megacephala were allowed to colonise naturally the corpses of rabbits that had died of malathion poisoning. The concentration of malathion increased gradually during the larval stages of C. megacephala reaching the maximum concentration in the third instar larvae. The concentration of malathion declined during prepupal stage and reached its lowest level among tenerals. The average malathion concentrations in C. megacephala growing in poisoned rabbit corpses left in a sunlit habitat were significantly higher (p<0.05) than those growing on poisoned rabbits left in a shaded habitat. The concentrations of malathion in the different stages of development of C. megacephala were moderately correlated (r = 0.51-0.69) with the administered doses as well as with those estimated in visceral organs. Thus, it would not be reliable to suggest the formulation of mathematical algorithms for relating the concentration of malathion found in the different stages of development of C. megacephala with those found in the visceral organs. However, in the context of forensic investigation, the qualitative detection of malathion in C. megacephala may prove useful in diagnosing the cause of death, since malathion is a common cause of accidental and suicidal deaths.
    Matched MeSH terms: Larva/drug effects; Larva/growth & development; Larva/chemistry
  13. Ismail A, Yusof S
    Mar Pollut Bull, 2011;63(5-12):347-9.
    PMID: 21377175 DOI: 10.1016/j.marpolbul.2011.02.014
    Several organisms have been used as indicators, bio-monitoring agents or test organisms in ecotoxicological studies. A close relative of the well established Japanese medaka, the Java medaka (Oryzias javanicus), has the potential to be a test organism. The fish is native to the estuaries of the Malaysian Peninsula, Thailand, Indonesia and Singapore. In this study, newly fertilised eggs were exposed to different concentrations of Cd and Hg. Observations were done on the development of the embryos. Exposure to low levels of Cd and Hg (0.01-0.05 ppm) resulted in several developmental disorders that led to death. Exposure to ≥1.0 ppm Cd resulted in immediate developmental arrest. The embryos of Java medaka showed tolerance to a certain extent when exposed to ≥1.0 ppm Hg compared to Cd. Based on the sensitivity of the embryos, Java medaka is a suitable test organism for ecotoxicology in the tropical region.
    Matched MeSH terms: Larva/drug effects
  14. Eamsobhana P, Wanachiwanawin D, Roongruangchai K, Song SL, Yong HS
    J Helminthol, 2017 Nov;91(6):767-771.
    PMID: 27890039 DOI: 10.1017/S0022149X16000857
    Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand.
    Matched MeSH terms: Larva/classification; Larva/genetics; Larva/physiology
  15. Teah MK, Chu YM, Shanmuganathan SD, Yeap TB
    BMJ Case Rep, 2020 Dec 09;13(12).
    PMID: 33298493 DOI: 10.1136/bcr-2020-237764
    Intubations are important live saving skills to maintain adequate ventilation and oxygenation. Common indications include impending upper airway obstruction, respiratory failure and impaired conscious level. Oral myiasis is an infrequently found disease which is characterised by ectoparasitic infestation of body tissues by fly maggots.We present a case report and share valuable experiences on a patient with massive airway myiasis causing upper airway obstruction which require emergency intubation.
    Matched MeSH terms: Larva
  16. Han HS, Yasmin L
    Vet Dermatol, 2020 Aug;31(4):335-e87.
    PMID: 32323413 DOI: 10.1111/vde.12855
    The most common fly species associated with screwworm myiasis in Southeast Asia is Chrysomya bezziana (Ch. bezziana), the Old-World screwworm. Treatment of screwworm myiasis in cats traditionally has comprised subcutaneous injection of ivermectin or oral administration of nitenpyram, combined with aggressive tissue debridement and larval removal under general anaesthesia. Two cats diagnosed with cutaneous myiasis caused by the larvae of Ch. bezziana were treated with lotilaner. In both cats, a single dose of lotilaner at 6-26 mg/kg, killed all larvae within 24 h, negating the need for general anaesthesia. Both cats were simultaneously infested with Lynxacarus radovskyi (L. radovskyi) which also was eradicated with lotilaner. No adverse reactions were observed and both cats recovered without complications.
    Matched MeSH terms: Larva/drug effects
  17. Cheong WC, Yap HH
    PMID: 4023816
    The pathogenicity of Bacillus sphaericus strain 1593 was tested against laboratory-reared larvae of four local species of mosquitoes of public health importance in Malaysia; Aedes aegypti, Anopheles balabacensis, Mansonia uniformis and Culex quinquefasciatus. The bacteria was shake-cultured at 28 +/- 1 degrees C for three days, using Glucose-Yeast Extract Salts medium. After which, the spores and vegetative cells were harvested and stored at 4 degrees C before use. Conditions for bioassays were mean temperature of 25 +/- 1 degrees C and relative humidity 65 +/- 5.0. Twenty third-instar larvae of each species were assayed in 90 ml of diluted spore solution. Each concentration and a control were replicated three times for each bioassay. Larval mortalities at 24 hours and 48 hours were taken and analyzed through Probit Analysis using a computer (IBM 370). LC50 values after 48 hours of exposure showed an increasing order of larval susceptibility as follows: Ae. aegypti (417.70 x 10(4)), An. balabacensis (45.84 x 10(4)), Ma. uniformis (18.23 x 10(4)) and Cx. quinquefasciatus (4.14 x 10(4) spores/ml). With the ability to kill 90% of the Cx. quinquefasciatus larvae tested with just a concentration of 10(5) spores/ml, B. sphaericus (strain 1593) has shown good potential as a biocontrol agent for this species of mosquito.
    Matched MeSH terms: Larva
  18. Yap FB
    Trans R Soc Trop Med Hyg, 2011 Jul;105(7):405-8.
    PMID: 21600621 DOI: 10.1016/j.trstmh.2011.04.002
    A retrospective study was undertaken to determine the clinical features of cutaneous larva migrans (CLM) seen in the Department of Dermatology, Hospital Kuala Lumpur (Kuala Lumpur, Malaysia) and to assess the rate of correct diagnosis made by the referring primary care doctors. Clinical records of all 31 patients with CLM seen between January 2006 and June 2010 were retrieved. The majority of patients were male. The mean age was 32.2 years. Pruritus was reported in 83.9% of cases and serpiginous tracts in 100%. The mean lesion count was 4.4 and the mean duration of disease before presentation was 3.1 weeks. The majority of skin lesions were on the buttock and lower extremities. Only 45.2% of patients had the correct diagnosis made by the referring primary care doctors. Older age of patients and lower number of lesions were associated with a higher rate of correct diagnosis. The low rate of correct diagnosis made by the referring primary care doctors to the dermatologists in this study warrants the need for education of not only primary care doctors but also future primary care providers, consisting of medical students, house officers and junior medical officers.

    Study site: Department of Dermatology, Hospital Kuala Lumpur
    Matched MeSH terms: Larva Migrans/diagnosis*; Larva Migrans/drug therapy; Larva Migrans/ethnology; Larva Migrans/pathology
  19. Yap FB
    Int J Infect Dis, 2010 Jun;14(6):e545.
    PMID: 19889564 DOI: 10.1016/j.ijid.2009.07.006
    Matched MeSH terms: Larva Migrans/diagnosis*; Larva Migrans/drug therapy*; Larva Migrans/parasitology
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