Displaying publications 1 - 20 of 45 in total

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  1. Kayode FI, Taiwo IE, Adeogun AO, Olalekan O, Chimdalu IP, Olayilola OI, et al.
    Afr Health Sci, 2023 Mar;23(1):255-261.
    PMID: 37545927 DOI: 10.4314/ahs.v23i1.27
    OBJECTIVE: We evaluated the susceptibility status of Anopheles gambiae in two communities of Ikorodu, Lagos, Nigeria to DDT, deltamethrin, lambda cyhalothrin and bendiocarb.

    METHODS: Anopheles immature stages were collected from their habitats in the surveyed community and allowed to emerge before exposure adult females to discriminating doses of WHO insecticides including DDT, deltamethrin, lambda cyhalothrin, bendiocarb and malathion. PBO synergistic bioassay was conducted for insecticides where the mosquito samples showed resistance. PCR assay was used for the detection of kdr mutation in the mosquitoes.

    RESULTS: Resistance to DDT (40% and 86%) and lambda cyhalothrin (75% and 84%) in Oke-Ota and Majidun respectively. Suspected resistance to deltamethrin (94.9%) and bendiocarb (93.5%) was recorded in Oke-Ota community and the mosquitoes were susceptible to malathion in both communities. KDR mutation (L1014F) from resistance samples from both locations though with a low frequency that significantly departs from Hardy-Weinberg's probability (P> 0.01). PBO synergized bioassay was able to increase knockdown, percentage mortality and restore full susceptibility to deltamethrin and bendiocarb.

    CONCLUSION: Results from this study indicates that the metabolic resistance mechanism is highly implicated in the resistance to different classes of insecticide in Ikorodu and this should be taken into consideration when implementing vector control activities in this area.

    Matched MeSH terms: Malathion
  2. Wan-Norafikah O, Chen CD, Sofian-Azirun M
    Saudi J Biol Sci, 2021 Jan;28(1):1010-1016.
    PMID: 33424394 DOI: 10.1016/j.sjbs.2020.11.040
    Aedes albopictus larvae obtained from different types of agricultural and non-agricultural localities in Peninsular Malaysia were subjected to several larvicides at World Health Organization (WHO) recommended dosages. Upon 24 h of WHO larval bioassay using two organochlorines and six organophosphates, high resistance against dichlorodiphenyltrichloroethane (DDT), temephos, chlorpyrifos and bromophos were demonstrated among all larval populations. Aedes albopictus larvae from both paddy growing areas (92.33% mortality) and rubber estates (97.00% mortality) were moderately resistant to dieldrin while only Ae. albopictus larvae from dengue prone residential areas (89.00% mortality) showed high resistance against dieldrin. All Ae. albopictus larval populations also developed either incipient or high resistance to both malathion (33.67%-95.33% mortality) and fenitrothion (73.00%-92.67% mortality). Only Ae. albopictus larvae from fogging-free residential areas that were tolerant to fenthion (97.33% mortality), whereas Ae. albopictus larvae from dengue prone residential areas were highly resistant to the same organophosphate (88.33% mortality). Cross resistance between intraclass and interclass larvicides of organochlorines and organophosphates were also exhibited in this study. The present study provided baseline data on various susceptibility levels of Ae. albopictus larval populations from different types of agricultural and non-agricultural localities against organochlorines and organophosphates at WHO recommended dosages. Nevertheless, further susceptibility investigations are suggested using revised doses of larvicides established from the local reference strain of Ae. albopictus to prevent the underestimation or overestimation of insecticide resistance level among Ae. albopictus field strains of larvae.
    Matched MeSH terms: Malathion
  3. Leong CS, Vythilingam I, Liew JW, Wong ML, Wan-Yusoff WS, Lau YL
    Parasit Vectors, 2019 May 16;12(1):236.
    PMID: 31097010 DOI: 10.1186/s13071-019-3472-1
    BACKGROUND: Dengue is a serious public health problem worldwide, including in Selangor, Malaysia. Being an important vector of dengue virus, Aedes aegypti are subjected to control measures which rely heavily on the usage of insecticides. Evidently, insecticide resistance in Ae. aegypti, which arise from several different point mutations within the voltage-gated sodium channel genes, has been documented in many countries. Thus, this robust study was conducted in all nine districts of Selangor to understand the mechanisms of resistance to various insecticides in Ae. aegypti. Mosquitoes were collected from dengue epidemic and non-dengue outbreak areas in Selangor.

    METHODS: Using the Center for Disease Control and Prevention (CDC) bottle assays, the insecticide resistance status of nine different Ae. aegypti strains from Selangor was accessed. Synergism tests and biochemical assays were conducted to further understand the metabolic mechanisms of insecticide resistance. Polymerase chain reaction (PCR) amplification and sequencing of the IIP-IIS6 as well as IIIS4-IIIS6 regions of the sodium channel gene were performed to enable comparisons between susceptible and resistant mosquito strains. Additionally, genomic DNA was used for allele-specific PCR (AS-PCR) genotyping of the gene to detect the presence of F1534C, V1016G and S989P mutations.

    RESULTS: Adult female Ae. aegypti from various locations were susceptible to malathion and propoxur. However, they exhibited different levels of resistance against dichlorodiphenyltrichloroethane (DDT) and pyrethroids. The results of synergism tests and biochemical assays indicated that the mixed functions of oxidases and glutathione S-transferases contributed to the DDT and pyrethroid resistance observed in the present study. Besides detecting three single kdr mutations, namely F1534C, V1016G and S989P, co-occurrence of homozygous V1016G/S989P (double allele) and F1534C/V1016G/S989P (triple allele) mutations were also found in Ae. aegypti. As per the results, the three kdr mutations had positive correlations with the expressions of resistance to DDT and pyrethroids.

    CONCLUSIONS: In view of the above outcomes, it is important to seek new tools for vector management instead of merely relying on insecticides. If the latter must be used, regular monitoring of insecticide resistance should also be carried out at all dengue epidemic areas. Since the eggs of Ae. aegypti can be easily transferred from one location to another, it is probable that insecticide-resistant Ae. aegypti can be found at non-dengue outbreak sites as well.

    Matched MeSH terms: Malathion
  4. Basari N, Mustafa NS, Yusrihan NEN, Yean CW, Ibrahim Z
    Trop Life Sci Res, 2019 Jan;30(1):23-31.
    PMID: 30847031 MyJurnal DOI: 10.21315/tlsr2019.30.1.2
    Ficus plants are commonly planted as ornamentals along roadsides in Malaysia. In 2010, Ficus plants in Kuala Terengganu were found to be attacked by a moth, identified as Trilocha varians. The larvae of this moth fed on Ficus leaves causing up to 100% defoliation. This study was conducted to determine the life cycle of T. varians under two different environmental temperatures and to control this pest using two different insecticides. Our findings showed that there were significant differences in the time taken for eggs to hatch and larval and pupation period between low and high environmental temperatures. Results also showed that fipronil had lower LT50 and LT95 than malathion. This study provides new information on the life history of T. varians under two different conditions and the efficiency in controlling T. varians larvae using insecticides. The results of this study are important for future management in controlling T. varians population especially in Kuala Terengganu, Malaysia.
    Matched MeSH terms: Malathion
  5. Al'Abri AM, Abdul Halim SN, Abu Bakar NK, Saharin SM, Sherino B, Rashidi Nodeh H, et al.
    J Environ Sci Health B, 2019;54(12):930-941.
    PMID: 31407615 DOI: 10.1080/03601234.2019.1652072
    This article demonstrates the first application of a copper-based porous coordination polymer (BTCA-P-Cu-CP) as a carbon paste electrode (CPE) modifier for the detection of malathion. The electrochemical behavior of BTCA-P-Cu-CP/CPE was explored using cyclic voltammetry (CV) while chrono-amperometry methods were applied for the analytical evaluation of the sensor performance. Under optimized conditions, the developed sensor exhibited high reproducibility, stability, and wide dynamic range (0.6-24 nM) with the limits of detection and sensitivity equal to 0.17 nM and 5.7 µAnMcm-1, respectively, based on inhibition signal measurement. Furthermore, the presence of common coexisting interfering species showed a minor change in signals (<4.4%). The developed sensor has been applied in the determination of malathion in spiked vegetable extracts. It exhibited promising results in term of fast and sensitive determination of malathion in real samples at trace level with recoveries of 91.0 to 104.4%. (RSDs < 5%, n = 3). A comparison of the two studied techniques showed that the HPLC technique is unable to detect malathion when the concentration is lower than 1.8 µM while 0.006 µM is detected with appropriate RSDs 0.2-5.2% (n = 3) by amperometric method. Due to the high sensitivity and selectivity, this new electrochemical sensor will be useful for monitoring trace malathion in real samples.
    Matched MeSH terms: Malathion
  6. Noor Albannia Natasya Jabi, Hazmi Awang Damit
    Borneo Akademika, 2019;3(1):1-9.
    MyJurnal
    Heterotrigona itama is a Malaysian stingless bee species that actively reared for meliponiculture. This stingless bee is cultivated in a commercial scale for its honey production, propolis and among the greatest commercial potential as crop pollinators. However, this species has been potentially exposed to agronomic practices, among which the use of synthetic insecticides against pests.The indirect toxicity effect of the post-insecticide had affected the mortalities of H. itama especially, to the foragers. Due to that, a study has been conducted to determine the lethal concentration of 50% (LC50) and 95% (LC95) of the selected insecticides against stingless bee forager workers through residual exposure. The bioassay test was conducted to the local stingless bee H. itama at Agricultural Research Station, Tenom. Four commonly used insecticides in crop protection; Deltamethrin, Chlorpyrifos, Cypermethrin and Malathion were tested at five concentrations that diluted with 500 ml of distilled water in three replications for each insecticide. Lethal concentrations (LC50 and LC95) were obtained from probit analysis after 1-hour dry residues exposure and 24-hour mortality observation. The result shows that; all four tested insecticides were harmful to H. itama through dry residue. Deltamethrin shows the higher value of LC50 (1.256 ml) and LC95 (3.582ml) that make it less toxic to the H. itama than cypermethrin, malathion, and chlorpyrifos, however, as the concentration gets higher it becomes more toxic.
    Matched MeSH terms: Malathion
  7. Rahim J, Ahmad AH, Ahmad H, Ishak IH, Rus AC, Maimusa HA
    J Am Mosq Control Assoc, 2017 Sep;33(3):200-208.
    PMID: 28854111 DOI: 10.2987/16-6607R.1
    Insecticide-based vector control approaches are facing challenges due to the development of resistance in vector mosquitoes. Therefore, a proper resistance surveillance program using baseline lethal concentrations is crucial for resistance management strategies. Currently, the World Health Organization's (WHO) diagnostic doses established for Aedes aegypti and Anopheles species are being used to study the resistance status of Aedes albopictus. In this study, we established the diagnostic doses for permethrin, deltamethrin, and malathion using a known susceptible reference strain. Five field-collected populations were screened against these doses, following the WHO protocol. This study established the diagnostic dose of malathion at 2.4%, permethrin at 0.95%, and deltamethrin at 0.28%, which differ from the WHO doses for Aedes aegypti and Anopheles spp. Among the insecticides tested on the 5 wild populations, only deltamethrin showed high effectiveness. Different susceptibility and resistance patterns were observed with permethrin, malathion, and dichloro-diphenyl-trichloroethane (DDT) at 4%. This study may assist the health authorities to improve future chemical-based vector control operations in dengue-endemic areas.
    Matched MeSH terms: Malathion/pharmacology*
  8. Dang K, Singham GV, Doggett SL, Lilly DG, Lee CY
    J Econ Entomol, 2017 04 01;110(2):558-566.
    PMID: 28115498 DOI: 10.1093/jee/tow296
    The performance of five insecticides (bendiocarb, deltamethrin, DDT, malathion, and imidacloprid) using three application methods (oil-based insecticide films on filter paper, and acetone-based insecticide deposits on two substrates: filter paper and glass) was assessed against a susceptible strain of Cimex lectularius (L.) and two resistant strains of Cimex hemipterus (F.). Substrate type significantly affected (P malathion and imidacloprid, which was largely due to high levels of resistance. The lower effectiveness for the insecticide acetone-based treatment on filter paper may be due to crystal bloom. This occurs when an insecticide, dissolved in a volatile solvent, is applied onto absorptive surfaces. The effect is reduced on nonabsorptive surfaces and slowed down with oil-based insecticides, whereby the oil forms a film on absorptive surfaces. These findings suggest that nonabsorptive surfaces should be used in bioassays to monitor insecticide resistance. If absorptive surfaces are used in bioassays for testing active ingredients, then oil-based insecticides should be preferably used.
    Matched MeSH terms: Malathion/pharmacology
  9. Rahim J, Ahmad AH, Kassim NF, Ahmad H, Ishak IH, Rus AC, et al.
    J Am Mosq Control Assoc, 2016 Sep;32(3):210-216.
    PMID: 27802400
    Dengue vector control still heavily relies on the use of chemical insecticides, and the widespread use of insecticides has led to resistance in mosquitoes. The diagnostic dose is a key part of resistance monitoring. The present study corroborates the discriminating lethal doses of temephos and malathion based on dose-response of known susceptible strain of Aedes albopictus following the World Health Organization (WHO) diagnostic test procedure. Late 3rd and early 4th instars were tested with a range of larvicides to determine the lethal concentrations (LC50 and LC99) values. A slightly higher diagnostic dose of 0.020 mg/liter as compared with the WHO-established value of 0.012 mg/liter was observed for temephos. Meanwhile, a malathion diagnostic dose of 0.200 mg/liter is also reported here since there are no such reported values by WHO. Doubling the LC99 values of susceptible strains, 3 of the 5 wild-collected populations showed resistance to temephos and 2 showed incipient resistance; all 5 populations showed incipient resistance to malathion. The revised and established lethal diagnostic dose findings from the current work are crucial to elaborate on the variation in susceptibility of Ae. albopictus in future resistance monitoring programs in Malaysia.
    Matched MeSH terms: Malathion*
  10. Rohani A, Aziz I, Zurainee MN, Rohana SH, Zamree I, Lee HL
    Trop Biomed, 2014 Mar;31(1):159-65.
    PMID: 24862056 MyJurnal
    Chemical insecticides are still considered as important control agents for malaria vector control. However, prolonged use of these chemicals may select mosquito vectors for resistance. In this study, susceptibility status of adult Anopheles maculatus collected from 9 localities in peninsular Malaysia, viz., Jeli, Temerloh, Pos Banun, Senderut, Jeram Kedah, Segamat, Kota Tinggi, Kluang and Pos Lenjang were determined using the standard WHO bioassay method in which the adult mosquitoes were exposed to standard insecticide impregnated papers malathion, permethrin, DDT and deltamethrin--at pre-determined diagnostic dosage. Deltamethrin was most effective insecticide among the four insecticides tested, with the LT50 of 29.53 min, compared to malathion (31.67 min), DDT (47.76 min) and permethrin (48.01 min). The effect of all insecticides on the laboratory strain was greater (with all insecticides demonstrated LT50 < 1 hour) than the field strains (deltamethrin 32.7, malathion 53.0, permethrin 62.0, DDT 67.4 min). An. maculatus exhibited low degree of resistance to all test insecticides, indicating that these chemical insecticides are still effective in the control of malaria vector.
    Matched MeSH terms: Malathion/pharmacology
  11. Low VL, Chen CD, Lim PE, Lee HL, Lim YA, Tan TK, et al.
    Pest Manag Sci, 2013 Dec;69(12):1362-8.
    PMID: 23404830 DOI: 10.1002/ps.3512
    Given that there is limited available information on the insensitive acetylcholinesterase in insect species in Malaysia, the present study aims to detect the presence of G119S mutation in the acetylcholinesterase gene of Culex quinquefasciatus from 14 residential areas across 13 states and a federal territory in Malaysia.
    Matched MeSH terms: Malathion/pharmacology*
  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: Malathion/analysis*
  13. Hidayati H, Nazni WA, Lee HL, Sofian-Azirun M
    Trop Biomed, 2011 Aug;28(2):425-37.
    PMID: 22041765
    Bioassay test against malathion had been carried out with larval and adult stages of Aedes aegypti. The mosquitoes were under selection pressure against malathion for forty-five consecutive generations. The rate of resistance development was measured by LC(50) and LT(50) values. The larvae and adult females, after subjection to malathion selection for 45 generations, developed high resistance level to malathion, with resistance ratio of 52.7 and 3.24 folds, respectively over control mosquitoes. Cross-resistance towards the same and different groups of insecticides was determined using the F44 and F45 malathion-selected adult females. Insecticides tested were DDT (4.0%), permethrin (0.75%), propoxur (0.1%), fenitrothion (1%), λ-cyhalothrin (0.05%) and cyfluthrin (0.15%). Results indicated that the mosquitoes were highly resistant to DDT and fenitrothion, moderately resistant to propoxur, tolerant to permethrin and λ-cyhalothrin, and very low resistant to cyfluthrin.
    Matched MeSH terms: Malathion/pharmacology*
  14. Jusoh A, Hartini WJ, Ali N, Endut A
    Bioresour Technol, 2011 May;102(9):5312-8.
    PMID: 21232934 DOI: 10.1016/j.biortech.2010.12.074
    In this batch study, the adsorption of malathion by using granular activated carbon with different parameters due to the particle size, dosage of carbons, as well as the initial concentration of malathion was investigated. Batch tests were carried out to determine the potential and the effectiveness of granular activated carbon (GAC) in removal of pesticide in agricultural run off. The granular activated carbon; coconut shell and palm shells were used and analyzed as the adsorbent material. The Langmuir and Freundlich adsorption isotherms models were applied to describe the characteristics of adsorption behavior. Equilibrium data fitted well with the Langmuir model and Freundlich model with maximum adsorption capacity of 909.1mg/g. The results indicate that the GAC could be used to effectively adsorb pesticide (malathion) from agricultural runoff.
    Matched MeSH terms: Malathion/isolation & purification*
  15. Selvi S, Edah MA, Nazni WA, Lee HL, Tyagi BK, Sofian-Azirun M, et al.
    Trop Biomed, 2010 Dec;27(3):534-50.
    PMID: 21399596 MyJurnal
    Aedes albopictus was bioassayed to determine resistance development to malathion (OP). Two methods were applied, including WHO larval bioassay to determine the susceptibility to lethal concentration (LC), and adult bioassay to determine lethal time (LT). Larvae from colonies that had undergone selection pressure with malathion to yield 50% mortality were further subjected to selection for subsequent 10 generations. Selection of Ae. albopictus with malathion could relatively induce a consistent resistance ratio of 1.0 throughout 10 generations. It was noted that Ae. albopictus larvae showed less susceptibility to malathion compared to adults. The susceptibility test of adult mosquitoes to diagnostic dosage of 5.0% malathion-impregnated paper showed a variety of susceptibility to malathion when compared to the susceptible strain. Bioassay results indicated that the LT50 values of malathion-selected Ae. albopictus ranged between 11.5 - 58.8 minutes for ten consecutive generations. Biochemical enzyme studies indicated that there was a significant difference (p < 0.05) in esterase level in malathion-selected mosquitoes compared to non-selected control. Electrophoretic patterns of non-specific esterases at different life stages in malathion-selected Ae. albopictus suggested that non-specific esterases do not play a role in resistance of malathion-selected Ae. albopictus.
    Matched MeSH terms: Malathion/pharmacology*
  16. Hossain F, Ali O, D'Souza UJ, Naing DK
    J Occup Health, 2010;52(6):353-60.
    PMID: 20924153
    OBJECTIVES: To determine the relationship between semen quality and exposure to pesticide residues.

    METHODS: A cross-sectional study was conducted among male farmers from 3 different communities in Sabah, Malaysia. A total of 152 farmers participated in this study of whom 62 farmers had been exposed to either paraquat or malathion or both to varying extents. Questionnaires were designed to record a history of pesticides exposure and other potential risk factors among farmers. All semen samples were collected, processed and analyzed by qualified personnel based on WHO guidelines. Volume, pH, sperm concentration, motility, morphology and WBC count were examined and recorded. The association between pesticide exposure and semen parameters was highly significant.

    RESULTS: The mean values of volume, pH, sperm concentration, motility, and WBC count were significantly less in the exposed group than in compared with the non-exposed group, with p<0.005. Those who were exposed to pesticides had greater risk of having abnormal semen parameters than those in with the non exposed group, with p values of less than 0.05. The comparison between semen qualities such as lower sperm count, motility and higher percentage of sperm abnormality of those exposed to different types of pesticides (paraquat and malathion) showed no significant differences.

    CONCLUSION: The results showed a significant decline in semen quality with a decline in sperm count, motility and higher percent of teratospermia among subjects with pesticide exposure, and those who were exposed to pesticides had significantly 3 to 9 times greater risk of having abnormal semen parameters.

    Matched MeSH terms: Malathion/adverse effects*
  17. Shaharom, N.A., Nyamah, M.A., Norashikin, M., Zaharah, M.S., Zuhaida, A.J., Norb, H., et al.
    MyJurnal
    The state of Johore suffered a massive flood disaster from 19th December 2006 to 1st January and from 12th January to 19th February 2007. The possible upsurge of dengue was of foremost concern and led to efforts in increasing control activities. Anyone with history of high fever with at least two symptoms of severe headache, pain behind the eyes, muscles and joint paint, rashes and petechiae were notified as dengue. Active and passive case finding was initiated at all 371 evacuation centres as well through health facilities and hospitals through an active surveillance system. Presumptive larval survey was also carried together with control activities by 46 health teams. Data were collected using the format ‘Aktiviti harian kawalan denggi di kawasan pos banjir- Lampiran E‘ and ‘Laporan aktiviti harian kawalan denggi di pusat pemindahan banjir – Lampiran D2’. Dengue serology and blood film for malaria was sent for as well as vector species identification. A total of 594 dengue cases were reported for the period of 19th December 2006 till 19th February 2007, which was an increase in comparison to the 5-year median but less than that reported in year 2006. However only 14 (2.3%) cases were from flood affected areas. During the flood phase, a total of 5,929 inspections were carried out at the evacuation centres with Aedes Index (AI) of 1.86%, while the post flood period showed a lower index. However Breteau Index (BI) and Container Index (CI) were higher. Preventive fogging were carried out at the evacuation centres using adulticides, thermal fogging was carried out at 21,959 premises (40.04% of inspected premises) and 350.6 L adulticides (malathion, fenitrothion and permethrin) were used. Dengue was expected to increase during flood as a result of increase Aedes potential breeding sites. However with intensive and integrated control activities, Johore was able to minimize the impact of flood for vector-borne diseases as seen from the low cases reported in flood related areas. A special guidelines for surveillance and control was developed during this flood as a reference for future occurrences.
    Matched MeSH terms: Malathion
  18. Rumiza Abd R, Osman K, Mohd Iswadi I, Raja Muhammad Z, Rogaya Abu H
    Trop Biomed, 2008 Dec;25(3):184-90.
    PMID: 19287355
    This study was conducted to examine the effect of malathion on the development of Chrysomya megacephala. A total of 12 adult Sprague-Dawley rats was divided into 4 groups. Each animal in the 4 groups was given orally 0 (control), 10, 25 and 50ml/kg body weight of malathion, respectively. Chrysomya megacephala larvae were then allowed to grow on the liver of carcass. Larvae development was estimated by means of weight and length, time of adult emergence and survival rate. Results indicated that for the first 6 to 30 hours, larvae from control group developed more rapidly than larvae feeding on tissue containing malathion. However, the 3 doses of malathion did not exhibit significant impact on larvae length and weight. The time required for adult emergence was significantly greater for malathion-treated colony which was 10 days compared to 7 days in control colony. Control larvae of C. megacephala had higher survival rate compared to larvae exposed to the three different doses of malathion. Analysis of the tissues indicated that all rats and fly samples were positive for malathion. Malathion concentration was highest in liver. It was concluded that the presence of malathion altered the development rate of C. megacephala and thus disrupted normal postmortem interval estimation.
    Matched MeSH terms: Malathion/pharmacokinetics*; Malathion/pharmacology
  19. Hidayati H, Nazni WA, Mohd SA
    Trop Biomed, 2008 Apr;25(1):75-9.
    PMID: 18600207 MyJurnal
    The standard laboratory strain was found to be heterozygous for susceptibility. Hence, an attempt was made to obtain a homozygous susceptible strain in Culex quinquefasciatus (Say) using single raft sib-selection method. Lab-bred females of Cx. quinquefasciatus from insectariums, Unit of Medical Entomology were used in the experiment. After blood feeding Cx. quinquefasciatus mosquitoes laid eggs in raft form, ten rafts selected randomly for the test. Each egg raft was introduced into a plastic tray from number one to number ten. Twenty-five third stage larvae from each tray were exposed to 17.5 microl from 500mg/l malathion in a paper cup label number 1 to number ten. In the bioassay, which had 100% mortality, the respective larva in that particular tray was bred to adult stage for the following generation. Less than 7days old female mosquitoes that emerged from F(0) were used in the test. The F(0) and the subsequent adult and larval stage generations were subjected to adult and larval bioassay. After selection for about 10 generations, a homozygous susceptible strain in Cx. quinquefasciatus was obtained.
    Matched MeSH terms: Malathion/pharmacology
  20. Selvi S, Edah MA, Nazni WA, Lee HL, Azahari AH
    Trop Biomed, 2007 Jun;24(1):63-75.
    PMID: 17568379 MyJurnal
    Larvae and adults of Culex quinquefasciatus were used for the test undertaken for malathion resistant strain (F61 - F65) and permethrin resistant strain (F54 - F58). The results showed that the LC50 for both malathion (F61 - F65) and permethrin (F54 - F58) resistant Cx. quinquefasciatus increased steadily throughout the subsequent five generations, indicating a marked development of resistance. The adult female malathion resistant strain have developed a high resistance level to malathion diagnostic dosage with a resistance ratio of 9.3 to 17.9 folds of resistance compared with the susceptible Cx. quinquefasciatus. Permethrin resistance ratio remained as 1.0 folds of resistance at every generation. It was obvious that malathion resistance developed at a higher rate in adult females compared to permethrin. Enzyme-based metabolic mechanisms of insecticide resistance were investigated based on the biochemical assay principle. From the results obtained obviously shows that there is a significant difference (p < 0.05) in esterase level in both malathion and permethrin selected strains. Female malathion selected strain has the higher level of esterase activity compared to the female permethrin selected strain at (0.8 to 1.04) alpha-Na micromol/min/mg protein versus (0.15 to 0.24) alpha-Na micromol/min/mg protein respectively. This indicated increased level of non-specific esterase is playing an important role in resistance mechanism in female malathion selected strain. Permethrin selected strain exhibited non-specific esterase activity at a very low level throughout the different life stages compared to malathion selected strain. This study suggests that life stages play a predominant role in conferring malathion and permethrin resistance in Cx. quinquefasciatus.
    Matched MeSH terms: Malathion/pharmacology*
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