Insect Repellent Research Articles

Essential oils extracted from Citrus macroptera and Homalomena aromatica (Spreng.) Schott. exhibit repellent activities against Aedes aegypti (Diptera: Culicidae)

Background & objectives: Mosquitoes alone transmit diseases to around 700 million individuals annually, killing approximately 0.7 million people every year worldwide. Considering the potential health risks linked with synthetic repellents, it has become vital to identify eco-friendly, natural repellents for mosquito control as well as to understand the underlying mechanism for mosquito repellent activity. To address this, objectives were set to extract essential oils from Citrus macroptera peel and Homalomena aromatica (Spreng.) Schott. rhizomes, evaluate their mosquito repellent activity against Aedes aegypti, and further explore their mosquito odorant receptor inhibition potential. Methods: The oils were extracted using Clevenger’s apparatus, and properties like specific gravity, refractive index, and boiling point were evaluated and characterised using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC-MS). Aedes aegypti mosquito eggs collected from the Indian Council of Medical Research (ICMR), Dibrugarh, were reared in the Department of Pharmaceutical Sciences, Research Laboratory, to obtain adult Aedes aegypti mosquitoes for the mosquito repellent activity evaluation of the essential oils using the Human Bait technique’. Molecular docking studies were performed for the oil components against mosquito odorant binding proteins. Further, toxicity studies of these two oils were evaluated against human dermal fibroblast adult (HDFa) cells. Results: The results revealed the presence of limonene (86.76%) and linalool (52.35%), respectively, in Citrus macroptera and Homalomena aromatica oils. It was found that the combination of the oils in a ratio of 1:1 showed mosquito repellent activity for up to 6.33 ± 0.23 h. Molecular docking studies showed the presence of major oil components having mosquito odorant receptor blocking potential comparable to N, N-diethyl-meta-toluamide (DEET), indicating a rationale for extended mosquito repellent action. Further, both of these oils were found to be non-cytotoxic against HDFa cells after 24 h. Interpretation & conclusion: The encouraging mosquito repellent activity of these two oils as compared to synthetic mosquito repellent DEET might pave the way for the development of novel herbal mosquito repellent formulations containing these essential oils.

Socially appropriate projects based on Termite Mound for the assistance of low-income clusters of rural societies

Abstract— In this Century, there has been tremendous development in applying the principles of engineering for the well-being of society because of advancements made in science, innovation, and technology. Science and innovation are helping us to answer for the upliftment of society. Engineering students of our institution undertook a 6-month-long project and addressed the issues faced by people from marginalized economic backgrounds. The study included farmers,women, and diabetic patients. The students conducted a review of this population by undertaking a survey. The students developed low-cost and easily affordable products developed from Termite mounds such as biofertilizers, biocontrol, mosquito repellant, and natural face cream. Due to the introduction of this Project course into the curriculum of the university, there has been tremendous improvement in the livelihood of the study population. The products developed by the students were provided to the study population and it has shown improvement in the daily life of the study population. The initiatives taken by the students and their faculty mentors have helped to improve the factors in the fields of agriculture, health, and the environment. Thus, this project course can be applied by every engineering institution for the assistance of low-income clusters of rural societies. Keywords— Biofertilizer; community service project; mosquito repellent; natural face cream

Extraction of chrysanthemum oil to produce organic insect repellent

Commercial repellent treatments incorporating plant-based components have recently gained favourable among users due to the fact They are considered “safe” in compared to long-established synthetic repellents however, this is usually not accurate. Many essential oils included in insect repellents and insecticides are very volatile, which adds to their short lifespan as insect repellents. This problem, however, can be resolved by adding fixatives to increase their lifespan. The objective of developing this organic repellent is to give a productive, totally natural preventive solution to repel cold-blooded and harmful insects. The aim of this project is to produce an organic repellent utilizing chrysanthemum oil and chrysanthemum oil + peppermint oil, and to test the efficacy of both end products. The experimental results exhibited that all three-parameter concentration revealed significant influence on 5 ml, 7 ml and 9 ml given the average mortality time of killing was 2.62 min, 2.34 min, and 3.38 min, respectively, as Chrysanthemum oil and Chrysanthemum oil + peppermint oil that the average mortality time of killing was 2.81 min, 3.04 min, and 2.79 min to cold-blooded insects such as cockroach, flies, and ants. As a result, there is a need to analysed natural materials as biopesticides since they are harmless to humans and the environment. Knowledge gained from ethnobotanical studies on traditional repellent plants is a great resource for the creation of new natural products.

Green synthesis of Eucalyptus globulus zinc nanoparticles and its use in antimicrobial insect repellent paint formulation in bulk industrial production

Mitigating climate change can be achieved by opting for sustainable, plant-based materials instead of relying on hazardous chemicals that come with various side effects. Various natural plant extracts find widespread application in synthesizing insect-repellent coatings, particularly in industries such as paint manufacturing. The increasing demand for these coatings has led us to find out the effects of different plant extracts for the efficient preparation of paints with more advanced impacts and low cost. For this purpose, zinc nanoparticles of Eucalyptus globulus L. and its extracts were used in this study due to their remarkable biocidal and antimicrobial activities. The extract was prepared by the process of oven-drying and heating followed by their filtration. Then, they were subjected to different phytochemical tests that were performed in which plant material did not contain flavonoids and glycol. The comparison of the size of nanoparticles was visible during the weighing which was found to be 4.451 mg. Advanced characterization techniques like FTIR, UV visible spectroscopy, and particle size analysis were adopted for the analysis of nanoparticles of plant extract. The FTIR analysis of the plant material was reported to lie in the range of 1000–1800 cm−1. On the other hand, the results of UV visible spectroscopy of nanoparticles of plant extract showed absorption peaks around 300 nm. The produced material was integrated into paint formulations to impart insect-repellent and antibacterial characteristics. Painted panels exhibited notable antibacterial efficacy, presenting an inhibition zone of 0.7 cm for Escherichia coli and 0.3 cm for Staphylococcus aureus when utilizing biocide. Plant nanoparticles yielded inhibition zones of 1 and 1.2, while aqueous extract resulted in zones of 0.2 and 0.5, respectively. A thorough evaluation of the paint's color attributes, including ΔL, Δa, Δb, and ΔE, indicated noteworthy differences. The CMC ΔE values from the trials exceeded 1, indicating a substantial change in shade. The batches of paints containing E. globulus extracts and nanoparticles were found to be lighter in color specifically green and yellow colors. Their antimicrobial and insect repellant activity was tested using the mosquitos of Aedes aegypti with an age of 4–5 weeks, revealing that formulations with plant extracts exhibited a 61 % effective period, greater than the 7 % observed in non-biocidal formulations. The paint responded best towards these mosquitoes in terms of repellency and the ultimate target of this study was achieved.

Use of insect repellent as personal protection among women of childbearing age in an arbovirus endemic area in Northeastern Brazil.

To analyze the factors associated with the individual use of insect repellent by women of childbearing age living in area endemic for arboviruses in Fortaleza, Brazil. This is a cohort study carried out between 2018 and 2019 with women aged between 15 and 39 years in Fortaleza, state of Ceará, Brazil. A total of 1,173 women users of one of the four selected primary health care units participated in the study. The outcome was divided into: continued use, discontinued use, and nonuse of insect repellent. Crude and adjusted multinominal logistic regression analysis was carried out guided by a hierarchical model, with presentation of the respective odds ratio (OR) and 95% confidence intervals (95%CI). The independent variables include: socioeconomic and demographic data, environmental and sanitary characteristics, knowledge of the insect repellent, and behavioral and pregnancy-related aspects. Only 28% of the participants reported using insect repellent during the two waves of the cohort. Women with higher education (OR=2.55; 95%CI 1.44-4.51); who are employed (OR=1.51; 95%CI 1.12-2.03); who received guidance from healthcare professionals (OR=1.74; 95%CI 1.28-2.36) and the media (OR=1.43; 95%CI 1.01-2.02); who intensified precautions against mosquitoes during the epidemic (OR=3.64; 95%CI 2.29-5.78); and who were pregnant between 2016 and 2019 (OR=2.80; 95%CI 1.83-4.30) had increased odds for continued use of insect repellent. The use of insect repellent among women of childbearing age was associated with a higher level of education, employment, guidance on insect repellent provided by healthcare professionals and the media, behavioral changes to protect against mosquitoes during the Zika virus epidemic, and pregnancy when occurring as of the beginning of the epidemic period.

Biopolymeric and lipid-based nanotechnological strategies for the design and development of novel mosquito repellent systems: recent advances.

Mosquitoes are the most medically important arthropod vectors of several human diseases. These diseases are known to severely incapacitate and debilitate millions of people, resulting in countless loss of lives. Over the years, several measures have been put in place to control the transmission of mosquito-borne diseases, one of which is using repellents. Repellents are one of the most effective personal protective measures against mosquito-borne diseases. However, conventional delivery systems of repellents (e.g., creams, gels, and sprays) are plagued with toxicity and short-term efficacy issues. The application of biopolymeric and lipid-based systems has been explored over the years to develop better delivery systems for active pharmaceutical ingredients including mosquito repellents. These delivery systems (e.g., solid lipid micro/nanoparticles, micro/nanoemulsions, or liposomes) possess desirable properties such as high biocompatibility, versatility, and controlled/sustained drug delivery, and thus are very important in tackling the clinical challenges of conventional repellent systems. Their capability for controlled/sustained drug release has improved patient compliance as it removes the need for consistent reapplication of repellents. They can also be engineered to reduce repellents' skin permeation, consequently improving their safety. However, despite the benefits that these systems offer very few of them have been successfully translated to the global market for commercial use, a vital challenge that previous reports have not thoroughly examined. The issue of limited clinical translation of novel repellent systems is a vital aspect to consider, as the ultimate goal is to move these systems from bench to bedside. As such, this study seeks to highlight the recent advances in the use of biopolymeric and lipid-based systems for the development of novel mosquito-repellent systems and also analyze the challenges that have limited the clinical translation of these systems while proposing possible strategies to overcome these challenges.

Mathematical modeling of the effects of vector control, treatment and mass awareness on the transmission dynamics of dengue fever

Dengue fever is a vital public health concern that affects about 40% of the world’s population. To address the dynamics of dengue disease, a mathematical model was formulated by incorporating three control strategies: vector control, treatment, and mass awareness. A stability analysis of the disease-free equilibrium (DFE) was conducted using the Jacobian matrix. The DFE was found to be locally and globally asymptotically stable when the effective reproductive number was less than one; otherwise, it was unstable. Additionally, an endemic equilibrium point (EEP) was identified. The global stability analysis of the EEP, performed using the Lyapunov method, showed that it is globally asymptotically stable whenever Re>1; otherwise, it is unstable. Bifurcation analysis revealed that the model system exhibits a forward bifurcation. Furthermore, sensitivity analysis of the effective reproduction number revealed that the most sensitive parameters are the biting rate (b) and insecticide efficacy (δ). Therefore, the results suggest that, in order to reduce new dengue cases, intervention strategies that decrease the biting rate, such as mosquito repellents and the use of insecticides to kill mosquitoes, should be implemented. Moreover, simulations were conducted for the extended model with vector control, treatment, and mass awareness. The results showed that the combination of vector control, treatment, and mass awareness has a more positive impact on the control of dengue fever than any single or paired intervention. Thus, for effective control of dengue fever, the three control measures should be implemented simultaneously, especially in endemic areas.

Enhancing Malaria Control Strategy: Optimal Control and Cost‐Effectiveness Analysis on the Impact of Vector Bias on the Efficacy of Mosquito Repellent and Hospitalization

This paper focuses on the impact of mosquito biting bias on the success of malaria intervention strategies. The initial model is developed considering the existence of symptomatic and asymptomatic humans, as well as vector bias. The model is then analyzed to demonstrate how the malaria‐endemic equilibrium always exists and is globally asymptotically stable if the basic reproduction number is larger than one. On the other hand, malaria will always go extinct in the population if the basic reproduction number is less than one. For intervention analysis, the model is extended by considering mosquito repellent and hospitalization as control strategies. The control reproduction number is shown analytically. Using the Pontryagin maximum principle, we characterize our optimal control problem. Several scenarios are conducted to observe the dynamics of control variables under different circumstances. We found that the intervention of mosquito repellent and hospitalization together is the most cost‐effective strategy to reduce the spread of malaria. Furthermore, we have shown that the more biased the vector attracted to infected individuals, the higher the cost needed to implement the control strategy.

Designing thermoreversible gels for extended release of mosquito repellent.

Mosquito-borne diseases are responsible for 700 000 deaths annually. Current outdoor protective strategies primarily focus on direct skin application of commercial repellents (i.e., aerosol sprays or topical lotions) which are typically limited to efficacy times of ≤10 hours due to rapid evaporation and dermal absorption. Consequently, frequent reapplication for continuous protection can increase associated health hazards and cause noncompliance. This study utilizes Hansen solubility parameter modeling to design physical gels composed of insect-repelling N,N-diethyl-meta-toluamide (DEET) and modacrylic copolymer poly(acrylonitrile-co-vinyl chloride) (P(AN-VC)). The P(AN-VC)/DEET composites exhibit tunable and reversible sol-gel transition temperatures that can meet the thermomechanical stability demands of the intended application and permit facile transition to commercial melt processing techniques such as injection molding, filament spinning, or film casting. P(AN-VC)/DEET gel films demonstrate mosquito repellency for more than half a year-performing longer than any other known material to date-due to the high reservoir of repellent and its desorption hindrance from the polymer matrix. Therefore, P(AN-VC)/DEET gels hold significant potential for extended protection against mosquitos and other biting arthropods.

Chemical composition of four essential oils and their adulticidal, repellence, and field oviposition deterrence activities against Culex pipiens L. (Diptera: Culicidae)

Effective mosquito repellents can limit the transmission of vector-borne diseases to humans. Consequently, there is an urgent need to develop mosquito control strategies that prioritize eco-friendly and cost-effective repellents. Essential oils (EOs) have enormous potential for mosquito repellency. Here, cinnamon, basil, eucalyptus, and peppermint EOs were investigated for adulticide and repellency properties against Culex pipiens as well on the oviposition behavior of gravid females from laboratory (lab test) and field (field test) populations. Cinnamon oil was an effective oviposition deterrent regardless of the population and had high adulticidal activity with toxicity index of 75.00% at 24 h of exposure, relative to deltamethrin. In addition, it exhibited effective repellency at 98.01% and 71.22% at 6.67 and 1.71 µl/cm2, respectively. Peppermint oil had the least adulticidal activity with toxicity index of 6.2% at 24 h, and it resulted in low repellency at 70.90% and 50.64% at 6.67 and 1.71 µl/cm2, respectively. On average, basil and eucalyptus oils showed some adulticidal efficiency, repellency, and oviposition deterrent activity. For all treatments, the oviposition deterrent index values of gravid females from natural populations (field test) were lower than those from lab-reared (lab test) females. Different ratios of monoterpenoids, phenylpropanoids, and fatty acids in the EOs tested likely account for the activity variations observed. Our results suggest cinnamon, basil, eucalyptus, and peppermint EOs, which are widely available, economical, and eco-friendly, with good potential for mosquito control strategies.

Shape and interactions of the synthetic repellent DEET.

N,N-Diethyl-3-methylbenzamide (DEET) is the most widely used insect repellent, exhibiting high efficiency against a wide variety of species. In this work, a comprehensive isolated-molecule investigation of DEET was conducted using chirp-excitation Fourier transform microwave (CP-FTMW) spectroscopy within the frequency range of 7-14 GHz. Four out of the eight theoretically predicted conformers were detected and grouped in pairs based on their rotational constants and planar moments of inertia. We also studied the non-covalent interactions of DEET by characterizing the attractive and repulsive forces, which could explain the energetic ordering of the four conformers. In addition, DEET has a methyl top bound to the benzyl ring which is predicted to rotate almost freely with respect to the molecular framework.

Alternative first-line malaria treatment.

Malaria is a disease affecting millions of people, especially in Africa, Asia, and South America, and has become a substantial economic burden. Because malaria is contracted through the bite of a mosquito vector, it is very challenging to prevent. Bed nets and insect repellents are used in some homes; others do not have or use them even when available. Thus, treatment measures are crucial to controlling this disease. Artemisinin-based combination therapy (ACT) is currently the first-line treatment for malaria. ACT has been used for decades, but recently, there has been evidence of potential resistance. This threat of resistance has led to the search for possible alternatives to ACT. In sub-Saharan Africa, Azadirachta indica, or simply neem, is a plant used to treat a variety of ailments, including malaria. Neem is effective against one of the more deadly malaria parasites Plasmodium falciparum. Reports show that neem inhibits microgametogenesis of P. falciparum and interferes with the parasite's ookinete development. Although there is substantial in vitro research on the biological activity of A. indica (neem), there is limited in vivo research. Herein, we discuss the in vivo effects of neem on malaria parasites. With A. indica, the future of malaria treatment is promising, especially for high-risk patients, but further research and clinical trials are required to confirm its biological activity.

Characteristics of Polish travellers admitted at the University Centre of Maritime and Tropical Medicine in Poland, 2023.

After COVID-19 restrictions were lifted, people started to travel again. Each year, thousands of Poles travel internationally, and many travel to tropical or subtropical destinations in Asia, Africa or South America. The aim of this article was to describe the characteristics of Polish travellers based on the information from a retrospective 12-month review of the medical records of Polish patients seeking pre-travel advice at the largest diagnostic and treatment travel medicine centre in Poland in 2023. The retrospective study was based on the analysis of medical records of 2,147 patients seeking pre-travel advice at the University Centre of Maritime and Tropical Medicine in Gdynia, Poland, between January and December 2023. The study focused on the analysis of the following patients' variables: age, sex, travel details (purpose of travel, length of travel, departure month, continents and countries to be visited). It also aimed to evaluate the range of prevention measures which were either recommended or administered to patients seeking pre-travel advice at the clinic (preventive vaccinations, chemoprophylaxis). In addition, it assessed the health status of the patients presenting at the travel medicine clinic; retrospective health assessments were based on the information from the interviews with the patients. Patients who sought pre-travel advice were mostly aged 36-65 years (49.5%), they were travelling for tourism purposes (78.3%), for a maximum period of 4 weeks (79.0%), mostly in November (15.2%) or in January (14.9%). Most travellers planned to visit Asia (55.5%) or Africa (29.0%); mainly Thailand (21.5%), Vietnam (8.5%), Kenya (8.3%) or India (8.2%). The most frequently administered immunoprophylaxis included vaccinations against typhoid fever and hepatitis A. Other commonly recommended/prescribed prevention measures included: insect repellents (69.3%), sunscreen (58.3%), antimalarials (35.8%), antithrombotic drugs (32.6%), and antidiarrheal drugs (25.6%). The analysis of patient interviews demonstrated that 61.8% of the travellers consulted at the clinic had no pre-existing medical conditions, while 38.2% required the use of chronic medications, mainly for allergies (14.3%), thyroid disorders (13.6%), cardiovascular diseases (9.3%), or psychiatric disorders (5.5%). A large number of Polish travellers visit destinations where the risk of infectious and non-infectious diseases is high. Providing patients with professional advice during a pre-travel consultation will help protect against travel-associated health problems.

A snapshot of a representative Brazilian state of illegal mining in indigenous areas during the era of malaria elimination.

Malaria is a public health problem and the cases diagnosed in the capital of Roraima, Brazil, show potential to characterize the burden of the disease in the state. This study aimed to describe the epidemiological, clinical, and laboratory aspects of malaria cases diagnosed in Boa Vista. For this purpose, a descriptive, cross-sectional study was conducted in two health units in the city, with individuals diagnosed and who agreed to respond the questionnaire. Of the total of 206 participants, characterized as men, mixed-race, and young, 96% (198) reported participating in illegal mining activity. Among the group of miners, 66% (131) came from other states of Brazil or other countries. The mines were mainly located in the Yanomami territory in Roraima. Plasmodium vivax infection occurred in 74% (153) of participants. In the miner's group, hospitalizations for severe malaria, previous malaria attacks, and delays in treatment after the onset of symptoms were reported. Although 73% (145) of miners reported knowing how malaria was transmitted, only 54% (107) used mosquito nets or repellents. The use of Artecom and chloroquine by miners is not for the complete treatment but only to relieve symptoms for returning to gold mines, highlighting the importance of molecular surveillance to antimalarial resistance. Indigenous peoples are considered vulnerable to malaria and miners promotes the increase of malaria in Roraima Indigenous Lands. Therefore, access to diagnosis and treatment in Indigenous areas invaded by miners is imperative to confront this disease that ravages Indigenous communities and threatens public health on a large scale to achieve the goal of eliminating malaria in the state.

Performance Evaluation Of Tea Tree Oil, Eucalyptus Oil & Mint Essential Oil On Cotton (Knit) Fabric As Mosquito Repellent Finish

Performance Evaluation Of Tea Tree Oil, Eucalyptus Oil & Mint Essential Oil On Cotton (Knit) Fabric As Mosquito Repellent Finish

Evaluation of mosquito repellency activity using mosquito cage method

Evaluation of mosquito repellency activity using mosquito cage method

Larvicidal, Insecticidal and Mosquito repellent activity of Scented Geranium (Pelargonium species) essential oil against Malarial Vector; Anopheles stephensi

Larvicidal, Insecticidal and Mosquito repellent activity of Scented Geranium (Pelargonium species) essential oil against Malarial Vector; Anopheles stephensi

A review on medicinal plants having mosquito repellents activity

A review on medicinal plants having mosquito repellents activity

Profile of Acute Poisoning and Its Outcome in Children Admitted to a Tertiary Care Hospital in Northeast India: A Cohort Study

Introduction: Acute poisoning in children is an important public health problem. It is a significant paediatric emergency in both developing and developed countries, leading to preventable morbidity and mortality. While there is substantial research literature on acute childhood poisoning from developed countries, there is a lack of data from developing countries like India due to inadequate and poor surveillance of poisoning-related data. Aim: To investigate the clinical and epidemiological profile, as well as the outcome, of acute poisoning in children admitted to the paediatric emergency department of a tertiary care hospital in Northeast India. Materials and Methods: This prospective cohort study was conducted in the Paediatrics department of Assam Medical College and Hospital, Dibrugarh, Assam, India, from April 1, 2021, to March 31, 2022. All children under the age of 12 years who presented to the paediatric department with a history of exposure to toxic substances were included in the study. The admitted children were assessed in terms of demographic variables, type of poison, route of poisoning, time of presentation, circumstances of poisoning, storage place of poison, clinical presentation, and interventions provided. Data were presented as mean and frequency. Results: A total of 78 children under 12 years of age were enrolled in the study, with a mean age of three years and three months at presentation. The majority of cases (96.2%) involved accidental poisoning, while a small proportion (3.8%) was due to suicidal poisoning. Of the two reported cases of suicidal poisoning, one involved a male child and the other involved a female child. Both children were above six years of age. The most common causes of poisoning were kerosene (34.6%), organophosphorus compounds (10.3%), and liquid mosquito repellents (9.1%). Conclusion: This study revealed both unintentional and intentional poisoning cases, with a high prevalence of accidental poisoning observed in children below three years of age. Kerosene was identified as the most common cause of childhood poisoning.

Evaluation of Airborne Particulate Matter and Volatile Organic Compounds Released by Three Types of Mosquito Repellents

Evaluation of Airborne Particulate Matter and Volatile Organic Compounds Released by Three Types of Mosquito Repellents