Monitoring Diptera species of medical and veterinary importance in Saudi Arabia: Comparative efficacy of lure-baited and chromotropic traps

Abstract A number of Diptera species have medical and veterinary importance as they cause myiasis and act as vectors for protozoans, helminth eggs, as well as bacterial pathogens. In this research here, eleven Diptera species were monitored in five locations in Northwestern part of Saudi Arabia, using three types of traps (lure-baited traps, window fly trap and yellow sticky traps). As a general trend, the dominant flies were Musca domestica, Musca sorbens, Calliphora sp., blowfly Chrysomya sp. and Sarcophaga haemorrhidalis. No significant differences were observed among the total number of flies collected indoor and outdoor at each site using different traps. In the slaughter house, the three types of traps showed significant differences in the mean of collected flies (F = 4.135). Lure-baited traps showed significant differences in the abundance of the flies collected over the other two traps. In vegetable markets, fly abundance varied significantly among the three types of traps (F = 13.934). In the animal market, the mean number of flies collected varied significantly among the three types of traps (F = 4.792). Similar patterns of variation in the number of flies collected by different traps were shown in farms (F = 4.747). However, in the residential area, no significant difference was detected in the mean number of flies collected by three traps (F = 2.620). M. domestica was found to be the most abundant species in all locations with a remarkable high abundance in animal facilities, and the lure-baited traps were found to be the most effective for monitoring fly abundance. Overall, our research adds basic knowledge for future control programs against flies of medical and veterinary importance in Saudi Arabia

Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera: Culicidae) in Saudi Arabia

Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC50: 0.045 and 0.032 mg/L) than Actikil (0.052 and 0.038 mg/L) and Bacilod (0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained (concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim (0.0003 and 0.0001 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal (0.0004 and 0.0003 mg/L) for both the field and laboratory strains, respectively. Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia

Suaeda maritima-based herbal coils and green nanoparticles as potential biopesticides against the dengue vector Aedes aegypti and the tobacco cutworm Spodoptera litura

The overuse of synthetic pesticides to control insect pests leads to physiological resistance and adverse environmental effects, in addition to high operational cost. Insecticides of botanical origin have been reported as useful for control of agricultural and public health insect pests. This research proposed a novel method of mangrove-mediated synthesis of insecticidal silver nanoparticles (AgNP) using Suaeda maritima, acting as a reducing and stabilizing agent. AgNP were characterized by UV–vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. S. maritima aqueous extract and mangrove-synthesized AgNP showed larvicidal and pupicidal toxicity against the dengue vector Aedes aegypti and the tobacco cutworm Spodoptera litura. In particular, LC50 of AgNP ranged from 8.668 (larva I) to 17.975 ppm (pupa) for A. aegypti, and from 20.937 (larva I) to 46.896 ppm (pupa) for S. litura. In the field, the application of S. maritima extract and AgNP (10 × LC50) led to 100% mosquito larval reduction after 72 h. Smoke toxicity experiments conducted on A. aegypti adults showed that S. maritima leaf-, stem- and root-based coils evoked mortality rates comparable or higher if compared to permethrin-based positive control (62%, 52%, 42%, and 50.2 respectively). In ovicidal experiments, egg hatchability was reduced by 100% after treatment with 20 ppm of AgNP and 250 ppm of S. maritima extract. Furthermore, low doses of the AgNP inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi. Overall, our results highlighted the potential of S. maritima-based herbal coils and green nanoparticles as biopesticides in the fight against the dengue vector A. aegypti and the tobacco cutworm S. litura

Magnetic nanoparticles are highly toxic to chloroquine-resistant Plasmodium falciparum, dengue virus (DEN-2), and their mosquito vectors

SURESH KUMAR SUBBIAH (A04156) / / / Kadarkarai Murugan,Jiang Wei,Mohamad Saleh Alsalhi,Marcello Nicoletti,Manickam Paulpandi,Christina Mary Samidoss,Devakumar Dinesh,Balamurugan Chandramohan,Chellasamy Paneerselvam,Jayapal Subramaniam,Chithravel Vadiva

Fern-synthesized nanopeprintss in the fight against malaria: LC/MS analysis of Pteridium aquilinum leaf extract and biosynthesis of silver nanopeprintss with high mosquitocidal and antiplasmodial activity

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum strains resistant to chloroquine. There is an urgent need to investigate new and effective sources of antimalarial drugs. This research proposed a novel method of fern-mediated synthesis of silver nanoparticles (AgNP) using a cheap plant extract of Pteridium aquilinum, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Phytochemical analysis of P. aquilinum leaf extract revealed the presence of phenols, alkaloids, tannins, flavonoids, proteins, carbohydrates, saponins, glycosides, steroids, and triterpenoids. LC/MS analysis identified at least 19 compounds, namely pterosin, hydroquinone, hydroxy-acetophenone, hydroxy-cinnamic acid, 5, 7-dihydroxy-4-methyl coumarin, trans-cinnamic acid, apiole, quercetin 3-glucoside, hydroxy-L-proline, hypaphorine, khellol glucoside, umbelliferose, violaxanthin, ergotamine tartrate, palmatine chloride, deacylgymnemic acid, methyl laurate, and palmitoyl acetate. In DPPH scavenging assays, the IC50 value of the P. aquilinum leaf extract was 10.04 μg/ml, while IC50 of BHT and rutin were 7.93 and 6.35 μg/ml. In mosquitocidal assays, LC50 of P. aquilinum leaf extract against Anopheles stephensi larvae and pupae were 220.44 ppm (larva I), 254.12 ppm (II), 302.32 ppm (III), 395.12 ppm (IV), and 502.20 ppm (pupa). LC50 of P. aquilinum-synthesized AgNP were 7.48 ppm (I), 10.68 ppm (II), 13.77 ppm (III), 18.45 ppm (IV), and 31.51 ppm (pupa). In the field, the application of P. aquilinum extract and AgNP (10 × LC50) led to 100 % larval reduction after 72 h. Both the P. aquilinum extract and AgNP reduced longevity and fecundity of An. stephensi adults. Smoke toxicity experiments conducted against An. stephensi adults showed that P. aquilinum leaf-, stem-, and root-based coils evoked mortality rates comparable to the permethrin-based positive control (57, 50, 41, and 49 %, respectively). Furthermore, the antiplasmodial activity of P. aquilinum leaf extract and green-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. IC50 of P. aquilinum were 62.04 μg/ml (CQ-s) and 71.16 μg/ml (CQ-r); P. aquilinum-synthesized AgNP achieved IC50 of 78.12 μg/ml (CQ-s) and 88.34 μg/ml (CQ-r). Overall, our results highlighted that fern-synthesized AgNP could be candidated as a new tool against chloroquine-resistant P. falciparum and different developmental instars of its primary vector An. stephensi. Further research on nanosynthesis routed by the LC/MS-identified constituents is ongoing

Green-synthesized CdS nano-pesticides: toxicity on young instars of malaria vectors and impact on enzymatic activities of the non-target mud crab Scylla serrata

Currently, nano-formulated mosquito larvicides have been widely proposed to control young instars of malaria vector populations. However, the fate of nanoparticles in the aquatic environment is scarcely known, with special reference to the impact of nanoparticles on enzymatic activity of non-target aquatic invertebrates. In this study, we synthesized CdS nanoparticles using a green protocol relying on the cheap extract of Valoniopsis pachynema algae. CdS nanoparticles showed high toxicity on young instars of the malaria vectors Anopheles stephensiand A. sundaicus. The antimalarial activity of the nano-synthesized product against chloroquine-resistant (CQ-r) Plasmodium falciparumparasites was investigated. From a non-target perspective, we focused on the impact of this novel nano-pesticide on antioxidant enzymes acetylcholinesterase (AChE) and glutathione S-transferase (GST) activities of the mud crab Scylla serrata. The characterization of nanomaterials was carried out by UV–vis and FTIR spectroscopy, as well as SEM and XRD analyses. In mosquitocidal assays, LC50 of V. pachynema-synthesized CdS nanoparticles on A. stephensi ranged from 16.856 (larva I), to 30.301 μg/ml (pupa), while for An. sundaicus they ranged from 13.584 to 22.496 μg/ml. The antiplasmodial activity of V. pachynema extract and CdS nanoparticles was evaluated against CQ-r and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of V. pachynema extract was 58.1 μg/ml (CQ-s) and 71.46 μg/ml (CQ-r), while nano-CdS IC50 was 76.14 μg/ml (CQ-s) and 89.21 μg/ml (CQ-r). In enzymatic assays, S. serrata crabs were exposed to sub-lethal concentrations, i.e. 4, 6 and 8 μg/ml of CdS nanoparticles, assessing changes in GST and AChE activity after 16 days. We observed significantly higher activity of GST, if compared to the control, during the whole experiment period. In addition, a single treatment with CdS nanoparticles led to a significant decrease in AChE activity over time. The toxicity of CdS nanoparticles and Cd ions in aqueous solution was also assessed in mud crabs, showing higher toxicity of aqueous Cd ions if compared to nano-CdS. Overall, our results underlined the efficacy of green-synthesized CdS nanoparticles in malaria vector control, outlining also significant impacts on the enzymatic activity of non-target aquatic organisms, with special reference to mud crabs

Earthworm-mediated synthesis of silver nanoparticles: a potent tool against hepatocellular carcinoma, Plasmodium falciparum parasites and malaria mosquitoes

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, LC50 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 IC50 were 49.3 μg/ml (CQ-s) and 55.5 μg/ml (CQ-r), while chloroquine IC50 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

Efficacy of chitosan silver nanoparticles from shrimp-shell wastes against major mosquito vectors of public health importance

Mosquito-borne diseases are causing serious damage to public health worldwide, and control of these deadly mosquito vectors is a major thrust area for epidemiologists and public health workers. Therefore, the present research reports an eco-friendly solution with multipotency of silver nanoparticle fabricated from shrimp shell biowaste in controlling mosquitoes and bacterial pathogens. The biofabricated chitosan silver nanoparticles (Cs-AgNPs) were confirmed by UV-visible spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, X-ray powder diffraction and zeta potential analysis. The TEM studies showed that the obtained Cs-AgNPs were mostly spherical in shape. Low doses of chitosan and Cs-AgNPs showed high mosquitocidal properties against both larvae and adult of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The LC50 (lethal concentration 50%) of Cs-AgNPs was 10.240 ppm (fourth instar larvae) and 9.671 ppm (adult) for An. stephensi; 11.349 ppm (fourth instar) and 12.015 ppm (adult) for Ae. aegypti and 12.426 ppm (fourth instar) and 12.965 ppm (adult) for Cx. quinquefasciatus. The concerning part of antibacterial studies showed that Cs-AgNP had significant inhibition on tested bacterial pathogens. Overall, this study shows that chitosan extracted from the shrimp shell wastes can be used as a potential source for controlling major mosquito vectors

The Effect of Some Plant Extracts on Mosquito Aedes aegypti (L.)

In this study, the biological effects of various concentrations of Melia azedarach, Rhazya stricta, Jatropha curcas, Artemisia herba alba, Calotropis procera, Matricharia chamomella and Diflubenzuron were assayed on an Aedes aegypti (L.) test population under controlled laboratory conditions. Concentration levels of responses were evaluated. Characteristics such as IC 50 and IC 90 the susceptibility of immature stages to these plant extracts and insect growth regulator and their accumulation effects were studied. The percentage mortality of the fourth instar of Ae. aegypti larvae increased significantly with latex concentrations, indicating a direct relationship between the concentration and different effects. The larval mortalities ranged between low or moderate. According the mode of action of different plant extracts and Diflubenzuron did not appear to give high percentage of mortality against larval stages, although in most cases a clearly delayed inhibition of adult emergence was noted. The survival pupae percentage that produced from treated with different concentrations indicated that increased significantly of pupal survival due to decreasing the concentrations. There were significantly larval mortality and inhibition adult emergency percent in the treated groups compared to the control group. The characteristics investigated here indicate that this plant extracts and insect growth regulators are effective alternatives for controlling the dengue vector