Displaying publications 1 - 20 of 605 in total

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  1. 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
  2. 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
  3. Cheah SX, Tay JW, Chan LK, Jaal Z
    Parasitol Res, 2013 Sep;112(9):3275-82.
    PMID: 23835922 DOI: 10.1007/s00436-013-3506-0
    This study focuses on the larvicidal, oviposition, and ovicidal effects of a crude extract of Artemisia annua against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus. Dried cells of Artemisia annua from cell suspension cultures were extracted using hexane. The extract showed moderate larvicidal effects against mosquitoes. At 24-h post treatment, the LC50 values for Anopheles sinensis, Aedes aegypti, and Culex quinquefasciatus were recorded as 244.55, 276.14, and 374.99 ppm, respectively. The percentage mortality of larvae was directly proportional to the tested concentration. Anopheles sinensis was found to be the most susceptible species, whereas Culex quinquefasciatus was the most tolerant to the Artemisia annua extract. The results indicated that the Artemisia annua extract showed concentration-dependent oviposition deterrent activity and had a strong deterrent effect. At 500 ppm, the percentage effective repellency was more than 85% compared with the control group for all the species, with oviposition activity index values of -0.94, -0.95, and -0.78 for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. In the ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of Artemisia annua extract was significantly lower than the control, with values of 48.84 ± 4.08, 38.42 ± 3.67, and 79.35 ± 2.09% for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. Artemisia annua was found to be more effective against Aedes aegypti and Anopheles sinensis compared with Culex quinquefasciatus. This study indicated that crude extract of A. annua could be a potential alternative for use in vector management programs.
    Matched MeSH terms: Larva
  4. Jaganathan A, Murugan K, Panneerselvam C, Madhiyazhagan P, Dinesh D, Vadivalagan C, et al.
    Parasitol Int, 2016 Jun;65(3):276-84.
    PMID: 26873539 DOI: 10.1016/j.parint.2016.02.003
    The development of parasites and pathogens resistant to synthetic drugs highlighted the needing of novel, eco-friendly and effective control approaches. Recently, metal nanoparticles have been proposed as highly effective tools towards cancer cells and Plasmodium parasites. In this study, we synthesized silver nanoparticles (EW-AgNP) using Eudrilus eugeniae earthworms as reducing and stabilizing agents. EW-AgNP showed plasmon resonance reduction in UV-vis spectrophotometry, the functional groups involved in the reduction were studied by FTIR spectroscopy, while particle size and shape was analyzed by FESEM. The effect of EW-AgNP on in vitro HepG2 cell proliferation was measured using MTT assays. Apoptosis assessed by flow cytometry showed diminished endurance of HepG2 cells and cytotoxicity in a dose-dependent manner. EW-AgNP were toxic to Anopheles stephensi larvae and pupae, LC(50) were 4.8 ppm (I), 5.8 ppm (II), 6.9 ppm (III), 8.5 ppm (IV), and 15.5 ppm (pupae). The antiplasmodial activity of EW-AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. EW-AgNP IC(50) were 49.3 μg/ml (CQ-s) and 55.5 μg/ml (CQ-r), while chloroquine IC(50) were 81.5 μg/ml (CQ-s) and 86.5 μg/ml (CQ-r). EW-AgNP showed a valuable antibiotic potential against important pathogenic bacteria and fungi. Concerning non-target effects of EW-AgNP against mosquito natural enemies, the predation efficiency of the mosquitofish Gambusia affinis towards the II and II instar larvae of A. stephensi was 68.50% (II) and 47.00% (III), respectively. In EW-AgNP-contaminated environments, predation was boosted to 89.25% (II) and 70.75% (III), respectively. Overall, this research highlighted the EW-AgNP potential against hepatocellular carcinoma, Plasmodium parasites and mosquito vectors, with little detrimental effects on mosquito natural enemies.
    Matched MeSH terms: Larva
  5. Mohamad M, Selamat MI, Ismail Z
    J Environ Public Health, 2014;2014:459173.
    PMID: 25309602 DOI: 10.1155/2014/459173
    In order to reduce the risk of dengue outbreak recurrence in a dengue outbreak prone area, the members of the community need to sustain certain behavior to prevent mosquito from breeding. Our study aims to identify the factors associated with larval control practices in this particular community. A cross-sectional study involves 322 respondents living in a dengue outbreak prone area who were interviewed using a pretested questionnaire. The level of knowledge about Aedes mosquitoes, dengue transmission, its symptoms, and personal preventive measures ranges from fair to good. The level of attitude towards preventive measures was high. However, reported level of personal larval control practices was low (33.2%). Our multiple logistic regression analysis showed that only those with a good level of attitude towards personal preventive measure and frequent attendance to health campaigns were significantly associated with the good larval control practices. We conclude that, in a dengue outbreak prone area, having a good attitude towards preventive measures and frequent participation in health campaigns are important factors to sustain practices on larval control.
    Matched MeSH terms: Larva
  6. Latif MA, Omar MY, Rafii MY, Malek MA, Tan SG
    C. R. Biol., 2013 Jul;336(7):354-63.
    PMID: 23932255 DOI: 10.1016/j.crvi.2013.06.006
    Morphological and host-plant relationship studies were conducted to differentiate two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice (Oryza sativa) and the other from Leersia hexandra, a weed grass. In morphometric studies based on esterase activities, an UPGMA dendrogram using 17 quantitative morphological characters, including stridulatory organs (courtship signal-producing organs) between two sympatric populations of N. lugens, one from rice and the other from L. hexandra, a weed grass revealed that both populations were separated from each other. An out-group, N. bakeri, was found to be completely different from the two sympatric populations of N. lugens. Rice plants were best suited for the establishment of the rice-infesting population, and L. hexandra was a favourable host for the Leersia-infesting population. The individuals derived from one host did not thrive on the other host, as shown by a significant reduction in survival and nymphal development, ovipositional preferences, ovipositional response, and egg hatchability. Therefore, morphological and host-plant relationship studies indicate that rice-associated population with high esterase activities and L. heaxandra-associated population with low esterase activities are two closely related sibling species.
    Matched MeSH terms: Larva
  7. Muslim A, Fong MY, Mahmud R, Lau YL, Sivanandam S
    Parasit Vectors, 2013;6:219.
    PMID: 23898840 DOI: 10.1186/1756-3305-6-219
    In 2011, we reported occurrence of natural human infections with Brugia pahangi, a filarial worm of dogs and cats, in a surburb of Kuala Lumpur, the capital city of Malaysia. Our preliminary entomological survey at that time suggested the mosquito species Armigeres subalbatus as the vector of the zoonotic infections. In this present report, we provide biological evidence to confirm our preliminary finding.
    Matched MeSH terms: Larva
  8. 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: Larva
  9. Lee HL, Chen CD, Masri SM, Chiang YF, Chooi KH, Benjamin S
    PMID: 19058596
    The field bioefficacy of a wettable granule (WG) formulation of Bacillus thuringiensis israelensis (Bti), VectoBac WG (Bti strain AM65-52) against dengue vectors, Aedes aegypti and Ae albopictus; was evaluated in a suburban residential area (TST) and in a temporary settlement site (KB) in the state of Selangor, Malaysia. Pre-control ovitrap surveillance of the trial sites indicated a high population of both types of Aedes mosquitoes. The populations were monitored continuously by weekly ovitrapping. Bti was sprayed biweekly at a dosage of 500 g/ha by using a mist-blower. The spray application was targeted into outdoor larval habitats. If required, Bti formulation was also applied directly into indoor water-holding containers at 8 g/1,000 l. Based on ovitrap surveillance, a significant reduction in Aedes populations was evident 4 weeks after initiating the first Bti treatment. The ovitrap index (OI) and the larvae density decreased drastically in both trial sites. In TST, the indoor OI was significantly reduced from 57.50 +/- 7.50% to 19.13 +/- 5.49% (p<0.05), while the outdoor OI decreased from 38.89 +/- 11.11% to 15.36 +/- 5.93%. In KB, similarly, the OI was significantly reduced by more than half, from 66.66 +/- 6.67% to 30.26 +/- 2.99% (p< 0.05). In all cases, the reduction in OI was paralleled by reduction in larval density.
    Matched MeSH terms: Larva
  10. 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: Larva
  11. Pang T
    Ann Acad Med Singap, 1987 Oct;16(4):612-6.
    PMID: 2895602
    Studies were carried out into the immunopathogenesis and laboratory diagnosis of dengue virus infections. Using an experimental system it was shown that cell-mediated immunity (CMI), as measured by delayed-type hypersensitivity (DTH) was induced in mice infected with dengue virus. The nature of the DTH response satisfies most criteria for a classical DTH reaction. In addition, it was also shown that infection with dengue virus causes a transient immunosuppression as measured by the immune response to other, unrelated antigens. With regard to the laboratory diagnosis of dengue infections, it was found that mosquito cells were a sensitive system for the isolation of dengue viruses and that the success of isolation was related to the antibody content of the serum. A new method for the rapid isolation of dengue viruses was also developed involving the intracerebral inoculation of mosquito larvae. By the use of this method viral antigens can be detected as early as 2-3 days after specimen inoculation. The significance of these findings in relation to the immunopathogenesis, prevention and control of disease syndromes due to dengue viruses is discussed.
    Matched MeSH terms: Larva
  12. Mahmuda A, Bande F, Abdulhaleem N, Abd Majid R, Awang Hamat R, Omar Abdullah W, et al.
    Iran J Parasitol, 2018 8 3;13(2):204-214.
    PMID: 30069204
    Background: Currently, most of the available serological diagnostic kits for strongyloidiasis are based on the use of the crude antigens of Strongyloides ratti, which are good, but with less sensitivity towards the infection. Hence, this study aimed to produce and evaluate monoclonal antibody for detecting soluble parasite antigen in animal sera.

    Methods: The study was conducted in the Department of Medical Microbiology and Parasitology, University Putra Malaysia in 2014-2017. Saline extract protein from the infective larvae of S. ratti was used to immunize BALB/c mice and subsequent fusion of the B-cells with myeloma cells (SP2/0) using 50% PEG. The hybridomas were cultured in HAT medium and cloned by limiting dilutions. Positive hybrids were screened by indirect ELISA. The ascites fluid from the antibody-secreting hybridoma was purified and the MAb was characterized by western-blots and evaluated in sandwich ELISA for reactivity against the homologous and heterologous antigens.

    Results: An IgG1 that recognizes a 30 and 34 kDa protein bands was obtained. The MAb was recognized by all S. ratti-related antigens and cross-reacted with only Toxocara canis antigens in both assays. The minimum antigen detection limit was found to be 5 ng/ml. All antibody-positive rat and dog sera evaluated have shown antigen-positive reactions in Sandwich-ELISA.

    Conclusion: The MAb produced, was able to detect antigens in strongyloidiasis and toxocariasis in animal models and may also be useful for the serological detection of active strongyloidiasis and visceral toxocariasis in human sera.

    Matched MeSH terms: Larva
  13. Murugan K, Suresh U, Panneerselvam C, Rajaganesh R, Roni M, Aziz AT, et al.
    Environ Sci Pollut Res Int, 2018 Apr;25(11):10456-10470.
    PMID: 28913784 DOI: 10.1007/s11356-017-0074-3
    The development of novel mosquito control tools is a key prerequisite to build effective and reliable Integrated Vector Management strategies. Here, we proposed a novel method using cigarette butts for the synthesis of Ag nanostructures toxic to young instars of the malaria vector Anopheles stephensi, chloroquine (CQ)-resistant malaria parasites Plasmodium falciparum and microbial pathogens. The non-target impact of these nanomaterials in the aquatic environment was evaluated testing them at sub-lethal doses on the predatory copepod Mesocyclops aspericornis. Cigarette butt-synthesized Ag nanostructures were characterized by UV-vis and FTIR spectroscopy, as well as by EDX, SEM and XRD analyses. Low doses of cigarette butt extracts (with and without tobacco) showed larvicidal and pupicidal toxicity on An. stephensi. The LC50 of cigarette butt-synthesized Ag nanostructures ranged from 4.505 ppm (I instar larvae) to 8.070 ppm (pupae) using smoked cigarette butts with tobacco, and from 3.571 (I instar larvae) to 6.143 ppm (pupae) using unsmoked cigarette butts without tobacco. Smoke toxicity experiments conducted against adults showed that unsmoked cigarette butts-based coils led to mortality comparable to permethrin-based positive control (84.2 and 91.2%, respectively). A single treatment with cigarette butts extracts and Ag nanostructures significantly reduced egg hatchability of An. stephensi. Furthermore, the antiplasmodial activity of cigarette butt extracts (with and without tobacco) and synthesized Ag nanostructures was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. The lowest IC50 values were achieved by cigarette butt extracts without tobacco, they were 54.63 μg/ml (CQ-s) and 63.26 μg/ml (CQ-r); while Ag nanostructure IC50 values were 72.13 μg/ml (CQ-s) and 77.33 μg/ml (CQ-r). In MIC assays, low doses of the Ag nanostructures inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi. Finally, the predation efficiency of copepod M. aspericornis towards larvae of An. stephensi did not decrease in a nanoparticle-contaminated environment, if compared to control predation assays. Overall, the present research would suggest that an abundant hazardous waste, such as cigarette butts, can be turned to an important resource for nanosynthesis of highly effective antiplasmodials and insecticides.
    Matched MeSH terms: Larva
  14. Han HS, Sharma R, Jeffery J, Noli C
    Vet Dermatol, 2017 Apr;28(2):239-e62.
    PMID: 27918123 DOI: 10.1111/vde.12403
    BACKGROUND: Infestation of wounds with the larvae of Callophorid flies is relatively common in countries where these parasites are found. The most common species associated with infections in Southeast Asia is Chrysomya bezziana (Ch. bezziana), the Old World screw worm. Treatment consists of either subcutaneous injection of ivermectin or oral administration of nitenpyram combined with aggressive tissue debridement under general anaesthesia.

    OBJECTIVES: To describe the treatment of cutaneous myiasis in three dogs caused by the larvae of Ch. bezziana in Malaysia and their treatment with spinosad plus milbemycin.

    RESULTS: In all dogs, a single oral dose of spinosad plus milbemycin at the recommended dosage of 31-62 mg/kg and 0.5-1.0 mg/kg, respectively, was able to kill all larvae within 8 h. Most dead larvae fell off the host and those remaining on the host were dead and easily removed with simple saline flushing and gentle debridement. Neither general anaesthesia nor aggressive mechanical debridement were needed in any patient.

    CONCLUSIONS AND CLINICAL IMPORTANCE: Oral spinosad plus milbemycin is a safe, licensed and effective treatment at the recommended dose for the rapid elimination of Ch. bezziana myiasis, with no need for sedation or anaesthesia.

    Matched MeSH terms: Larva
  15. Takaoka H, Srisuka W, Saeung A, Otsuka Y, Choochote W
    Trop Biomed, 2012 Sep;29(3):381-90.
    PMID: 23018501
    Simulium (Nevermannia) chomthongense sp. nov. is described from female, male, pupal and larval specimens collected from Doi Inthanon National Park and Doi Phahompok National Park, Chiang Mai, Thailand. This new species, first reported as S. (Eusimulium) sp. A, and later regarded as S. (N.) caudisclerum Takaoka & Davies, described from peninsular Malaysia, is distinguished from S. (N.) caudisclerum in the male by the number of enlarged upper-eye facets and the relative size of the hind basitarsus against the hind tibia and femur, and in the pupa by the relative length of the stalks of paired filaments against the common basal stalk and the color of the dorsal surface of abdominal segments 1- 3 (or 4). Taxonomic and molecular notes are provided to separate this new species from four other known species of the vernum species-group, which share an accessory sclerite on the larval abdomen, a rare characteristic in this species-group.
    Matched MeSH terms: Larva
  16. Yang F, Guo KX, Yang DQ, Liu RD, Long SR, Zhang X, et al.
    Trop Biomed, 2020 Jun 01;37(2):458-470.
    PMID: 33612815
    A T. spiralis serine protease 1.2 (TsSP1.2) was identified in the muscle larvae (ML) and intestinal larvae surface/excretory-secretory (ES) proteins by immunoproteomics. The aim of this study was to determine the TsSP1.2 function in the process of T. spiralis intrusion, growth and reproduction by using RNA interference (RNAi). RNAi was used to silence the expression of TsSP1.2 mRNA and protein in the nematode. On 2 days after the ML were electroporated with 2 µM of TsSP1.2-specific siRNA 534, TsSP1.2 mRNA and protein expression declined in 56.44 and 84.48%, respectively, compared with untreated ML. Although TsSP1.2 silencing did not impair worm viability, larval intrusion of intestinal epithelium cells (IEC) was suppressed by 57.18% (P < 0.01) and the suppression was siRNA-dose dependent (r = 0.976). Infection of mice with siRNA 534 transfected ML produced a 57.16% reduction of enteral adult burden and 71.46% reduction of muscle larva burden (P < 0.05). Moreover, silencing of TsSP1.2 gene in ML resulted in worm development impediment and reduction of female fertility. The results showed that silencing of TsSP1.2 by RNAi inhibited larval intrusion and development, and reduced female fecundity. TsSP1.2 plays a crucial role for worm invasion and development in T. spiralis life cycle, and is a potential vaccine/drug target against Trichinella infection.
    Matched MeSH terms: Larva
  17. Ahammad AK, Asaduzzaman M, Asakawa S, Watabe S, Kinoshita S
    Mech. Dev., 2015 Aug;137:53-65.
    PMID: 25842264 DOI: 10.1016/j.mod.2015.02.006
    Teleosts are unique among vertebrates due to their indeterminate muscle growth, i.e., continued production of neonatal muscle fibers until death. However, the molecular mechanism(s) underlying this property is unknown. Here, we focused on the torafugu (Takifugu rubripes) myosin heavy chain gene, MYHM2528-1, which is specifically expressed in neonatal muscle fibers produced by indeterminate muscle growth. We examined the flanking region of MYHM2528-1 through an in vivo reporter assay using zebrafish (Danio rerio) and identified a 2100 bp 5'-flanking sequence that contained sufficient promoter activity to allow specific gene expression. The effects of enhanced promoter activity were observed at the outer region of the fast muscle and the dorsal edge of slow muscle in zebrafish larvae. At the juvenile stage, the promoter was specifically activated in small diameter muscle fibers scattered throughout fast muscle and in slow muscle near the septum separating slow and fast muscles. This spatio-temporal promoter activity overlapped with known myogenic zones involved in teleost indeterminate muscle growth. A deletion mutant analysis revealed that the -2100 to -600 bp 5'flanking sequence of MYHM2528-1 is essential for promoter activity. This region contains putative binding sites for several representative myogenesis-related transcription factors and nuclear factor of activated T-cell (NFAT), a transcription activator involved in regeneration of mammalian adult skeletal muscle. A significant reduction in the promoter activity of the MYHM2528-1 deletion constructs was observed in accordance with a reduction in the number of these binding sites, suggesting the involvement of specific transcription factors in indeterminate muscle growth.
    Matched MeSH terms: Larva/physiology
  18. Teh CH, Nazni WA, Nurulhusna AH, Norazah A, Lee HL
    BMC Microbiol, 2017 Feb 16;17(1):36.
    PMID: 28209130 DOI: 10.1186/s12866-017-0936-3
    BACKGROUND: Antimicrobial resistance is currently a major global issue. As the rate of emergence of antimicrobial resistance has superseded the rate of discovery and introduction of new effective drugs, the medical arsenal now is experiencing shortage of effective drugs to combat diseases, particularly against diseases caused by the dreadful multidrug-resistant strains, such as the methicillin-resistant Staphylococcus aureus (MRSA). The ability of fly larvae to thrive in septic habitats has prompted us to determine the antibacterial activity and minimum inhibitory concentrations (MICs) of larval extract of flies, namely Lucilia cuprina, Sarcophaga peregrina and Musca domestica against 4 pathogenic bacteria [Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa and Escherichia coli] via a simple and sensitive antibacterial assay, resazurin-based turbidometric (TB) assay as well as to demonstrate the preliminary chemical profile of larval extracts using gas chromatography-mass spectrophotometry (GC-MS).

    RESULTS: The resazurin-based TB assay demonstrated that the L. cuprina larval extract was inhibitory against all tested bacteria, whilst the larval extract of S. peregrina and M. domestica were only inhibitory against the MRSA, with a MIC of 100 mg ml(-1). Subsequent sub-culture of aliquots revealed that the larval extract of L. cuprina was bactericidal against MRSA whilst the larval extracts of S. peregrina and M. domestica were bacteriostatic against MRSA. The GC-MS analysis had quantitatively identified 20 organic compounds (fatty acids or their derivatives, aromatic acid esters, glycosides and phenol) from the larval extract of L. cuprina; and 5 fatty acid derivatives with known antimicrobial activities from S. peregrina and M. domestica.

    CONCLUSION: The resazurin-based turbidometric assay is a simple, reliable and feasible screening assay which evidently demonstrated the antibacterial activity of all fly larval extracts, primarily against the MRSA. The larval extract of L. cuprina exerted a broad spectrum antibacterial activity against all tested bacteria. The present study revealed probable development and use of novel and effective natural disinfectant(s) and antibacterial agent(s) from flies and efforts to screen more fly species for antibacterial activity using resazurin-based TB assay should be undertaken for initial screening for subsequent discovery and isolation of potential novel antimicrobial substances, particularly against the multi-drug resistant strains.

    Matched MeSH terms: Larva/chemistry*
  19. Nordin O, Donald W, Ming WH, Ney TG, Mohamed KA, Halim NA, et al.
    PLoS One, 2013;8(3):e58805.
    PMID: 23527029 DOI: 10.1371/journal.pone.0058805
    Dengue is the most important mosquito-borne viral disease. No specific treatment or vaccine is currently available; traditional vector control methods can rarely achieve adequate control. Recently, the RIDL (Release of Insect carrying Dominant Lethality) approach has been developed, based on the sterile insect technique, in which genetically engineered 'sterile' homozygous RIDL male insects are released to mate wild females; the offspring inherit a copy of the RIDL construct and die. A RIDL strain of the dengue mosquito, Aedes aegypti, OX513A, expresses a fluorescent marker gene for identification (DsRed2) and a protein (tTAV) that causes the offspring to die. We examined whether these proteins could adversely affect predators that may feed on the insect. Aedes aegypti is a peri-domestic mosquito that typically breeds in small, rain-water-filled containers and has no specific predators. Toxorhynchites larvae feed on small aquatic organisms and are easily reared in the laboratory where they can be fed exclusively on mosquito larvae. To evaluate the effect of a predator feeding on a diet of RIDL insects, OX513A Ae. aegypti larvae were fed to two different species of Toxorhynchites (Tx. splendens and Tx. amboinensis) and effects on life table parameters of all life stages were compared to being fed on wild type larvae. No significant negative effect was observed on any life table parameter studied; this outcome and the benign nature of the expressed proteins (tTAV and DsRed2) indicate that Ae. aegypti OX513A RIDL strain is unlikely to have any adverse effects on predators in the environment.
    Matched MeSH terms: Larva
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