Gas Chromatography-Mass Spectrometry ; methods ; Humans ; Malathion ; metabolism ; urine

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.
Malathion ; Chrysomya megacephala ; development aspects ; Adult ; Carbon ion

Laboratory-bred females of Culex quinquefasciatus, Aedes aegypti and Aedes albopictus from the insectarium, Unit of Medical Entomology, Institute for Medical Research were used in the experiment. The late third stage of the F0 larvae which survived the high selection pressure of malathion, permethrin and temephos were reared and colonies were established from adults that emerged. Cx. quinquefasciatus larvae were subjected to selection by malathion and permethrin for 40 generations, Ae. aegypti larvae to malathion, permethrin and temephos for 32 generations and Ae. albopictus larvae were selected against malathion and permethrin for 32 generations and 20 generations against temephos. The rate of resistance development was measured by LC50 value. Cx. quinquefasciatus larvae developed higher resistance to malathion and permethrin compared to Ae. aegypti and Ae. albopictus. On the whole, permethrin resistance developed at a faster rate than malathion and temephos.
Permethrin ; Malathion ; Cancer resistance to treatment ; Aedes aegypti ; Aedes albopictus

During the period from May to October 1969, the authors carried out a series of tests with the aim to ascertain the present status of susceptibility of adult cockraoches to various insecticides. The tests on the susceptibility of cockroaches to dieldrin, D.D.V.P., Diazinon; Dibrom, Malathion and lindane were performed with the topical application and the residual film methods under the conditions of 26 degrees C and 80% of relative humidity. The insects tested were collected from Seoul City and were reared at the laboratory. Some of the important results so far obtained can be summarized as follows: The median lethal doses (LD(50)) of the five insecticides against female adult cockroaches were: 0.4 ug/roach or 4.02 ug/body weight (gm) by Dieldrin, 0.29/roach or 2.88 ug/body weight (gm) by D.D.V.P., 0.29 ug/roach or 2.96 ug/body weight (gm) by Diazinon, 0.54 ug/roach or 5.37 ug/body weight (gm) by Dibrom, and 2.96 ug/roach or 29.60 ug/body weight (gm) by Malathion. And those against male adult cockroaches were: 0.18 ug/roach or 3.29 ug/body weight (gm) by Dieldrin, 0.27 ug/roach or 4.89 ug/body weight (gm) by D.D.V.P., 0.16 ug/roach or 2.91 ug/body weight (gm) by Diazinon, 0.49 ug/roach or 8.97 ug/body weight (gm) by Dibrom, and 1.32 ug/roach or 24.19 ug/body weight (gm) by Malathion. The level of susceptibility of adult cockroaches to the insecticides tested was 1.0-1.6 times higher as compared with the results obtained on the Japanese Takashi strain. The median knockdown times (LT(50)) of the female adult cockroaches by insectcides at 1% concentration of 3 mg per square centimetre were 1.82 hours by Malathion, 1.36 hours by Diazinon, 0.56 hours by Lindane, 0.50 hours by Dibrom, and 2.56 hours by D.D.V.P. A marked difference was seen to exist between the males and the females. The female cockroaches were more resistant than the male to Dieldrin, Diazinon and Malathion.
parasitology-arthropoda-cockcroach-Blattella germanica ; chemotherapy ; Dieldrin ; D.D.V.P. ; Diazinon ; Dibrom ; Malathion ; lindane ; resistance

The results of the tests carried out in 1971 strongly suggested that a considerable portion of the flea population in MR 2 had developed resistance not only against DDT but also malathion and dieldrin. There is also the possibility of the fleas developing a resistance to diazinon and lindane. Thus careful consideration should be given to the continuous use of diazinon. In areas where fleas had developed a resistance to malathion, further tests should be conducted continuously to confirm the possible development of resistance. Other insecticides which have not been used in Vietnam for any purpose should be ready to be substituted, if the development of resistance is confirmed.
parasitology-arthropoda-flea-Xenopsylla cheopis ; resistance ; Vietnam ; DDT ; dieldrin ; diazinon ; lindane ; malathion

OBJECTIVE: To analyze the density, distribution and insecticide resistance of Aedes albopictus in Ningbo City in 2021, so as to provide insights into formulation of dengue fever control strategies. METHODS: Four administrative villages were randomly selected from each county (district) in Ningbo City from April to November, 2021, to investigate the indoor population density of Aedes larvae, and the Breteau index (BI) was calculated. The population density of adult mosquitoes was investigated in residential areas, parks/bamboo forests, waste tire stacking sites/waste stations/construction sites in each county (district). On June 2021, larvae of the natural strain A. albopictus were collected from epidemic sites of dengue fever in Ningbo City in 2018, and raised in laboratory. Then, larvae and female mosquitoes without blood feeding were selected for insecticide resistance bioassays, while insecticide-sensitive strains of A. albopictus served as controls. The resistance of A. albopictus larvae to deltamethrin, beta-cypermethrin, propoxur, temephos and dichlorvos using the impregnation method, and the medium lethal concentration (LC₅₀) and resistance ratio (RR) were calculated. The resistance of adult A. albopictus to beta-cypermethrin, permethrin, deltamethrin, propoxur and malathion was determined using the tube bioassay, and the mosquito mortality was calculated. RESULTS: A total of 10 072 small water containers from 9 935 households were investigated in Ningbo City in 2021, and there were 1 276 containers with Aedes larvae detected, with an average BI of 12.89. Totally 1 422 mosquito nets were allocated and 954 female A. albopictus were captured, with an average net trapping index of 1.34 mosquitoes/(net·hour). Both larval and adult A. albopictus mosquitoes were found from April to November, and the density of larval A. albopictus peaked in September (BI = 21.21), while the density of adult A. albopictus peaked in August, with a net trapping index of 2.38 mosquitoes/(net·hour). The LC₅₀ values of delta-methrin, beta-cypermethrin, propoxur, temephos and dichlorvos were 0.017 4, 0.000 9, 0.364 1, 0.038 1 mg/L and 0.001 6 mg/L against larvae of natural strains of A. albopicchus, with RRs of 49.66, 25.53, 9.65, 2.24 and 6.06, and the mortality rates of adult mosquitoes were 66.00% (66/100), 69.39% (68/98), 25.00% (25/100), 98.97% (96/97) and 100.00% (98/98) 24 hours post-treatment with 0.08% beta-cypermethrin, 0.03% deltamethrin, 0.4% permethrin, 0.05% propoxur, and 0.5% malathion for 24 h, respectively. CONCLUSIONS A. albopictus is widely distributed in Ningbo City, with a high population density and presents high-level resistance to common pyrethroid insecticides. The population density and insecticide resistance of A. albopictus requires to be reinforced.
Animals ; Female ; Malathion ; Temefos ; Aedes ; Propoxur ; Permethrin ; Dichlorvos ; Mosquito Vectors ; Larva ; Dengue/prevention & control*

The aquatic quality of the Naktong river after two of three months in June, 1991 with phenol spillage from a electrical factory in Kumi was investigated. The samples were collected at six sites of the Naktong river basin and Kachang and Kongsan lakes. Phenol was not detected from all water samples. Turbidity was very much increased to the down stream in the Naktong river. The BOD and COD values exceeded the 2nd grade(3 mg/l) of the Korean standard quality of Environmental Water Act at the all sampling sites of the Naktong river. Especially, the value of COD at Kaejin (12.5 mg/l) was poorly classified as to the 5th grade of water class for the environmental quality standards. Organophosphorous pesticides such as parathion, malathion, fenitrothion and diazinon were investigated but not detected. Diazinon was only detected at the Ilson bridge(1.42 ppb), Okkye stream(6.95 ppb), Waekwan bridge(0.32 ppb), Gangjung reservior(0.13 ppb), Kaejin(0.05 ppb). Of the carbamates such as carbanyl, isoprocarb and cabofuran, the carbofuran was detected all sites except tap water, and Kachang and Kongsan lakes. The content of heavy metals such ans Cd, Pb, Zn, Fe, Mn, Hg were not exceeding for drinking water standards at the all sampling region, but only mecury was detected from Okkye stream(0.018ppb) and Kaejin(0.09ppb). In the regions of Kachang and Kongsan lakes, the content of heavy metals were lower than that of reservoir of Naktong river.
Carbamates ; Carbofuran ; Diazinon ; Drinking Water ; Fenitrothion ; Gyeongsangbuk-do* ; Korea* ; Lakes ; Malathion ; Metals, Heavy ; Parathion ; Pesticides ; Phenol* ; Rivers* ; Water ; Water Quality

BACKGROUND: Workers in pesticide manufacturing industries are constantly exposed to pesticides. Genetic biomonitoring provides an early identification of potential cancer and genetic diseases in exposed populations. The objectives of this biomonitoring study were to assess DNA damage through comet assay in blood samples collected from industry workers and compare these results with those of classical analytical techniques used for complete blood count analysis. METHODS: Samples from controls (n = 20) and exposed workers (n = 38) from an industrial area in Multan, Pakistan, were subjected to various tests. Malathion residues in blood samples were measured by gas chromatography. RESULTS: The exposed workers who were employed in the pesticide manufacturing industry for a longer period (i.e., 13-25 years) had significantly higher DNA tail length (7.04 μm) than the controls (0.94 μm). Workers in the exposed group also had higher white blood cell and red blood cell counts, and lower levels of mean corpuscular hemoglobin (MCH), MCH concentration, and mean corpuscular volume in comparison with normal levels for these parameters. Malathion was not detected in the control group. However, in the exposed group, 72% of whole blood samples had malathion with a mean value of 0.14 mg/L (range 0.01-0.31 mg/L). CONCLUSION: We found a strong correlation (R2 = 0.91) between DNA damage in terms of tail length and malathion concentration in blood. Intensive efforts and trainings are thus required to build awareness about safety practices and to change industrial workers' attitude to prevent harmful environmental and anthropogenic effects.
Blood Cell Count ; Chromatography, Gas ; Comet Assay ; DNA ; DNA Damage ; Environmental Monitoring* ; Erythrocyte Count ; Erythrocyte Indices ; Hematologic Tests ; Leukocytes ; Malathion ; Occupations* ; Pakistan ; Pesticides* ; Tail

AIMTo observe the effect of the aqueous extract of hypocotyls of the plant Lepidium meyenii (Maca) on spermatogenic damage induced by the organophosphate insecticide malathion in mice.

METHODSMice were treated with 80 mg/kg of malathion in the presence or absence of an aqueous extract of Maca, which was orally administered 7, 14 or 21 days after injection of the malathion. Stages of the seminiferous epithelium were assessed by transillumination on days 0, 7, 14 and 21.

RESULTSThe administration of Maca increased significantly the length of stage VIII on days 7, 14 and 21 of treatment compared with the controls. An increase in the length of stage IX occurred on day 14 of treatment. Malathion affected spermatogenesis by reducing the lengths of stage IX on day 7, stages VII and IX-XI on day 14 and a recovery of stages IX-XII on day 21. The magnitude of alteration in the length of stage IX produced by malathion was significantly reduced by Maca on days 7 and 14. The length of stage VIII was increased when Maca was administered to mice treated with malathion. Assessment of the relative length of stages of the seminiferous epithelium showed that Maca treatment resulted in rapid recovery of the effect of malathion.

CONCLUSIONMaca enhances spermatogenesis following spermatogenic damage caused by the organophosphorous pesticide.

Animals ; Drug Administration Schedule ; Hypocotyl ; Lepidium ; Malathion ; adverse effects ; Male ; Mice ; Phytotherapy ; Plant Extracts ; therapeutic use ; Spermatogenesis ; drug effects ; Time Factors ; Treatment Outcome

OBJECTIVETo evaluate the reproduction toxicity of the mixture composed of dichlorvos, dimethoate and malathion synergistic effect on male mice, and further explore its possible mechanisms.

METHODSThe 105 male mice were divided into 7 groups, including control (0 mg/kg), mix low (10.8 mg/kg), mix medium (21.5 mg/kg), mix high dose (43.0 mg/kg), dichlorvos (5.1 mg/kg), dimethoate (12.6 mg/kg) and malathion (25.3 mg/kg) group. The oral gavage for successive 35 days, and the mice were sacrificed on the 36(th) day. The body weight, and the quantity, activity and morphology of sperms were examined. The levels of sexual hormone were measured, including testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E(2)). Pathological changes of testicle and epididymis were observed by morphology, pathology and electron microscope.

RESULTSAfter 14 days exposure, the body weights of the mice were lower in the mix-high dose group ((22.40 ± 3.07) g) than those in control group ((26.73 ± 2.82) g) (P < 0.05). After 28 days exposure, the body weights of the mice were also lower in the mix-medium dose group ((30.00 ± 4.93) g) than those in control group ((33.13 ± 3.29) g) (P < 0.05). The sperm counts and sperm motility decreased significantly as the toxic concentration arised. Comparing to control group ((373.33 ± 14.65)×10(6)/g weight of epididymis and (75.17 ± 7.68)%), the spermatozoa count and sperm motility had decreased in mix-medium and mix-high dose groups ((321.17 ± 18.19)×10(6)/g weight of epididymis, (225.00 ± 19.67)×10(6)/g weight of epididymis, and (64.67 ± 9.91)%, (57.83 ± 9.66)%), and the sperm abnormality rates were higher in mix-medium and mix-high groups ((43.33 ± 8.66)‰ and (55.00 ± 13.80)‰) comparing to those in control group ((32.67 ± 8.17)‰). Compared to those in control group (FSH (1.41 ± 0.20), E(2)(17.32 ± 2.72), LH (8.75 ± 1.32) and T (3.45 ± 0.80) nmol/L), the serum level of FSH (3.14 ± 0.62) and (3.85 ± 0.37) nmol/L, E(2) (36.81 ± 6.68) and (43.76 ± 9.82) nmol/L in mix-medium and mix-high dose group increased (P < 0.01), while the level of LH (5.21 ± 1.23) and (4.27 ± 1.09) nmol/L and T (1.37 ± 0.38) and (0.73 ± 0.18) nmol/L decreased (P < 0.01). The morphological and ultramicrostructure results of testicle and epididymis indicated that the mature sperm numbers were decreased, and the cacoplastic sperm head and the tail of spermatozoon were observed in mix-high dose groups.

CONCLUSIONThe dichlorvos, dimethoate and malathion mixture had synergistic reproductive toxicity to the testicle and epididymis structure and function, and thus leading to the process of generation cell cytopoiesis abnormalities, simultaneously the hypothalamus-pituitary-gonad axis were also affected and thus resulted in parasecretion.

Animals ; Body Weight ; Dichlorvos ; toxicity ; Dimethoate ; toxicity ; Malathion ; toxicity ; Male ; Mice ; Mice, Inbred ICR ; Organ Size ; Sperm Count ; Sperm Motility ; Spermatozoa ; drug effects ; Toxicity Tests