This study investigated the removal of parabens, N,N-diethyl-m-toluamide (DEET), and phthalates by ozonation. The second-order rate constants for the reaction between selected compounds with ozone at pH 7 were of (2.2 +/-0.2) X 10(6) to (2.9 +/-0.3) X 10(6) M 1/s for parabens, (2.1+/- 0.3) to (3.9 +/-0.5) M-1/s for phthalates, and (5.2 +/-0.3) M-1/s for DEET. The rate constants for the reaction between selected compounds with hydroxyl radical ranged from (2.49 +/-0.06) x 10(9) to (8.5 +/-0.2) x 10(9) M-1/s. Ozonation of selected compounds in secondary wastewater and surface waters revealed that ozone dose of 1 and 3 mg/L yielded greater than 99% depletion of parabens and greater than 92% DEET and phthalates, respectively. In addition, parabens were found to transform almost exclusively through the reaction with ozone, while DEET and phthalates were transformed almost entirely by hydroxyl radicals (.OH).
Yearly, huge amounts of sock refuse are discarded into the environment. Socks contain many molecules, and worn ones, which are rich in smell-causing bacteria, have a strong influence on animals' behaviors. But the impacts of sock odor on the oviposition behavior of dengue vectors are unknown. We assessed whether Aedes albopictus changes its oviposition activity in response to the presence of used socks extract (USEx) in potential breeding grounds, using choice and no-choice bioassays (NCB). When furnished even chances to oviposit in two sites holding USEx and two others containing water (control), Ae. albopictus deposited significantly less eggs in USEx than in water sites. A similar pattern of oviposition preference was also observed when there were more oviposition options in water. When there were greater oviposition opportunities in USEx sites, Ae. albopictus oviposited preferentially in water. Females laid significantly more eggs during the NCB involving water than USEx. Also, significantly more mature eggs were retained by females in the NCB with USEx than in that with water. These observations strongly suggest the presence of molecules with either repellent or deterrent activities against Ae. albopictus females and provide an impetus to advocate the integration of used socks in dengue control programs. Such applications could be a realistic end-of-life recourse to reroute this waste from landfills.
During the early months of 1985 and 1986, 408 non-immune British soldiers undertook training in the jungles north of Kota Tinggi, in southern Malaysia. In this geographical location, where malaria transmission is now light, a combination of strict personal antimosquito measures plus proguanil 200 mg daily produced effective, safe protection, with only a single case of vivax malaria occurring. Given the limited malaria risk, however, the results of this study should be extrapolated only with caution to other areas of Malaysia.
Based on an ethnobotanical study on use for plant species against mosquito bites in the Kota Tinggi District, Johor State, Malaysia, 3 plants selected for study, Citrus aurantifolia (leaves), Citrus grandis (fruit peel), and Alpinia galanga (rhizome), were extracted using hydrodistillation to produce essential oils. These essential oils were then formulated as a lotion using a microencapsulation process and then tested for their repellent effect against Aedes aegypti. N,N-diethyl-m-toluamide (deet) was also prepared in the same formulation and tested for repellency as controls. Four commercial plant-based repellent (KAPS(®), MozAway(®), BioZ Natural(®), and Mosiquard(®)) also were incorporated in the bioassay for comparison purposes. Bioassays revealed that at 20% concentration all repellent formulations demonstrated complete protection for 2 h and >90% for 4 h post-application. The A. galanga-based formulation provided the greatest level of protection (98.91%), which extended for 4 h post-application and was not significantly different from deet at similar concentration. When compared with commercial plant-based repellents (KAPS(®), MozAway(®), and BioZ Natural(®)), the 3 lotion formulations showed significantly better protection against Ae. aegypti bites, providing >90% protection for 4 h. In conclusion, our 3 plant-based lotion formulations provided acceptable levels of protection against host-seeking Ae. aegypti and should be developed.
The potential of natural organic compounds as a repellent in biodegradable organic pot is budding into one of the new agriculture innovation. The use of recyclable materials in the production of the pot can reduce the excessive waste disposal problem and thus prevent pollution problems. The objectives are to recycle old newspapers into biodegradable pot for seedling of plants and to repel plant insect pests using organic compounds (Pandanus sp., Petroselinum crispum and Alium sativum). The production of the biodegradable pot incorporates the use of waste materials such as old newspapers and coconut husk together with natural organic materials such as tapioca flour, Pandanus amaryllifolius (pandan leaf), Petroselinum crispum (parsley) and Alium sativum (garlic). This product is distinguishable among others as it is environmental-friendly since the pot can naturally break over time (biodegradable). The aroma from the Pandanus amaryllifolius, Petroselinum crispum and Alium sativum can repel flying and crawling insect that may attack the crops. The organic insect-repellent biodegradable pot has a potential in replacing plastic polybags since the crops planted in the pot can be directly replanted in the soil without the need of disposing the pot. Root is allowed to grow through the pot where later on, it will be degraded. Apart from that, this pot has high commercial values since it is easy to be handled, low in production cost, eco-friendly where only recyclable and natural organic materials were used, and the most crucial point is it can act as an insect repellent.
Simian malaria is a zoonotic disease caused by Plasmodium knowlesi infection. The common natural reservoir of the parasite is the macaque monkey and the vector is the Anopheles mosquito. Human cases of P. knowlesi infection has been reported in all South East Asian countries in the last decade, and it is currently the most common type of malaria seen in Malaysia and Brunei. Between 2007-2017, 73 cases of P. knowlesi infection were notified and confirmed to the Ministry of Health in Brunei. Of these, 15 cases (21%) were documented as work-related, and 28 other cases (38%) were classified as probably related to work (due to incomplete history). The occupations of those with probable and confirmed work related infections were border patrol officers, Armed Forces and security personnel, Department of Forestry officers, boatmen and researchers. The remaining cases classified as most likely not related to work were possibly acquired via peri-domestic transmission. The risk of this zoonotic infection extends to tourists and overseas visitors who have to travel to the jungle in the course of their work. It can be minimised with the recommended use of prophylaxis for those going on duty into the jungles, application of mosquito/insect repellants, and use of repellant impregnated uniforms and bed nets in jungle camp sites.
This study examined the tunneling activity and the behaviour of two subterranean termites, Globitermes sulphurues and Coptotermes gestroi treated with four plant extracts, namely Pyllanthus niruri, Azadirachta indica, Leucaena leucocephala and Andrographis paniculata. All plants were extracted with three different solvents (methanol, hexane and water) and were diluted into three concentrations (500, 5,000 and 10,000 ppm). A group of 50 workers and 2 soldiers were tested and observed daily during the exposure in order to determine their survivorship and behaviour. Both sections were scored to determine their tunneling activities after seven days. There was a significant difference of tunneling activities of C. gestroi on sand treated with plant extracts (X2(2) = 31.790, p < 0.0001) with a mean rank of 8.50 for methanolic extracts and 32.50 for both hexane and water extracts. Meanwhile, no significant difference was observed on tunneling activity of G. sulphureus on treated sand (X2(2) = 2.200, p = 0.333) with a mean rank of 20.72 for methanolic extracts, 26.31 for water extracts and 26.47 for hexane extracts. Results showed that plants extracted with methanol demonstrated strong repellent properties with 0 tunneling activity on the treated sand and low survivorship of both termites. Moreover, both termites did not survive (0%) when they were treated with methanolic extracts at 10,000 ppm. They also displayed a different behaviour post-exposure such as avoidance, gradually losing the ability to walk and low feeding consumption. These results indicate that there is a strong termiticidal activity of plants extracted with methanol against C. gestroi and G. sulphureus.
A taxonomic description of all castes of Colobopsis explodens Laciny & Zettel, sp. n. from Borneo, Thailand, and Malaysia is provided, which serves as a model species for biological studies on "exploding ants" in Southeast Asia. The new species is a member of the Colobopsis cylindrica (COCY) group and falls into a species complex that has been repeatedly summarized under the name Colobopsis saundersi (Emery, 1889) (formerly Camponotus saundersi). The COCY species group is known under its vernacular name "exploding ants" for a unique behaviour: during territorial combat, workers of some species sacrifice themselves by rupturing their gaster and releasing sticky and irritant contents of their hypertrophied mandibular gland reservoirs to kill or repel rivals. This study includes first illustrations and morphometric characterizations of males of the COCY group: Colobopsis explodens Laciny & Zettel, sp. n. and Colobopsis badia (Smith, 1857). Characters of male genitalia and external morphology are compared with other selected taxa of Camponotini. Preliminary notes on the biology of C. explodens Laciny & Zettel, sp. n. are provided. To fix the species identity of the closely related C. badia, a lectotype from Singapore is designated. The following taxonomic changes within the C. saundersi complex are proposed: Colobopsis solenobia (Menozzi, 1926), syn. n. and Colobopsis trieterica (Menozzi, 1926), syn. n. are synonymized with Colobopsis corallina Roger, 1863, a common endemic species of the Philippines. Colobopsis saginata Stitz, 1925, stat. n., hitherto a subspecies of C. badia, is raised to species level.
Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket.
Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD50) of C. curvignathus was 945 mg/kg, whereas LD50 value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices.
Termites encompass a various range of destruction of crops and capable of decomposing woods. The widely being used of hazardous chemical pesticides has develop many health problems to the users. Hence, the aim of this study was to substitute the use of hazardous chemical pesticides to herbs based pesticides as repellent agent against rubber termites (Coptotermes curvignathus), which is safer and easier to use. The selected herbs species for this study are lemongrass (Cymbopogon citratus), garlic (Allium sativum) and wild mint (Mentha arvensis). As for C.curvignathus, they were obtained from Forest Research Institute Malaysia (FRIM), Kepong, Selangor, Malaysia. Khaya wood (Khaya senegalensis) (3cm x 2cm x 2cm) is the woods sample that being used. All woods samples were treated with all the selected herbs extract. The repellent testing was conducted for 21 days. The result obtained showed that the three herbs were effective to be used as repellent when compared to percentage weight loss of control, which is 23.58%. The percentages of weight loss of treated groups using aqueous extraction of herbs were 0.61% (lemongrass), 1.56% (mint), and 1.72% (garlic), whereas for methanol extraction of herbs were 0.52% (lemongrass), 1.13% (mint) and 1.55% (garlic). From Analysis of Variance (ANOVA), there is significant different in mean among group with F=275.49, p- value=0.000
Ylang-ylang (Cananga odorata Hook. F. & Thomson) is one of the plants that are exploited at a large scale for its essential oil which is an important raw material for the fragrance industry. The essential oils extracted via steam distillation from the plant have been used mainly in cosmetic industry but also in food industry. Traditionally, C. odorata is used to treat malaria, stomach ailments, asthma, gout, and rheumatism. The essential oils or ylang-ylang oil is used in aromatherapy and is believed to be effective in treating depression, high blood pressure, and anxiety. Many phytochemical studies have identified the constituents present in the essential oils of C. odorata. A wide range of chemical compounds including monoterpene, sesquiterpenes, and phenylpropanoids have been isolated from this plant. Recent studies have shown a wide variety of bioactivities exhibited by the essential oils and the extracts of C. odorata including antimicrobial, antibiofilm, anti-inflammatory, antivector, insect-repellent, antidiabetic, antifertility and antimelanogenesis activities. Thus, the present review summarizes the information concerning the traditional uses, phytochemistry, and biological activities of C. odorata. This review is aimed at demonstrating that C. odorata not only is an important raw material for perfume industry but also considered as a prospective useful plant to agriculture and medicine.
Primary prevention is the most effective measure in dengue prevention and control. The objectives were (i) to determine the level of knowledge and practice of dengue control amongst the study community, and (ii) to explore the factors affecting practice of dengue control in the study area. A cross-sectional study was conducted in a semi-urban Town of Malaysia, using a structured questionnaire covering sociodemography, knowledge related to dengue, knowledge related to Aedes mosquito and preventive measures against the disease. For comparison of survey responses, chi-square test was applied for categorical data. To explore the factors affecting the practice of dengue control, a linear regression model was introduced. Almost all of the respondents (95%) had heard about dengue. Overall, misconceptions of dengue transmission were identified and the practice of dengue control in the study population was insufficient. About half (50.5%) had misconceptions that Aedes can breed in dirty water and the preferred biting time is dusk or sunset (45.6%). Only 44.5% of the households surveyed had covered their water containers properly. Significant associations were found between knowledge scores of dengue and age (P = 0.001), education level (P = 0.001), marital status (P = 0.012), and occupation (P = 0.007). In regression analysis, only the knowledge of dengue was significantly and positively associated with practice on dengue control. A future study with larger samples and more variables to assess the knowledge, attitudes and practices of dengue control is recommended.