Insect Repellent Research Articles

Mosquito Repellents: A Guide to the Availability and Effectiveness of Commercial Formulations in Argentina

Mosquito Repellents: A Guide to the Availability and Effectiveness of Commercial Formulations in Argentina

Repellency Effects, Cytotoxicity Assessment and Chemical Compositions of Citrus limon Seeds Extracts and Fractions Against Anopheles gambiae sl Mosquitoes

Background: Citrus limon seeds have limited exploration, compared to other parts. The increasing prevalence of mosquito menace prompted the investigation into the repellent effects of the seed n-hexane extract and fractions of Citrus limon (Rutaceae) against adult Anopheles gambiae sl mosquitoes. The cytotoxicity and chemical constituents of the 100% n-Hexane Fraction (HF) were also evaluated. Methods: Successive extraction was done with cold-maceration using, n-hexane, Ethyl Acetate (EA) and methanol. The three solvent extracts were screened against Anopheles gambiae sl mosquitos, using human bait method, at doses, 1.5, 2.5 and 5.0 mg/ml and with Deet and acetone used as positive and negative controls respectively. The n-hexane extract was further fractionated with column chromatography. Ten fractions (100% n-hexane, 10, 20, 30, 40, 60, 80% EA in n-hexane, 100% EA, 50% methanol in EA, and 100% methanol) were collected, and all tested at a single optimized dose of 5 mg/ml for 2 hr. The cytotoxicity and the chemical constituents of HF were determined using brine shrimp lethality test and gas chromatography-mass spectrometry respectively. Results: N-hexane extract and HF, both at 5 mg/ml, showed the most protective effect of 97.52 and 89.40% respectively, compared with standard (Odomos Deet) 100% activity, with no significant difference (p>0.05) between the three. HF was toxic with LC50 values of 29.2354 ppm. Thirty compounds representing 79.25% of HF were identified. Major compounds present in the fraction were heptadecanamine (8.31%), N-(3-methylbutyl) acetamide (7.89%), 2-ethyl- 1-hexanamine (6.65%). Conclusion: This promising repellent activity further justified the traditional usage of Citrus limon as mosquito repellent.

Repellents against Aedes aegypti bites: synthetic and natural origins

Dengue fever, transmitted by mosquitoes of the Aedes genus, particularly Aedes aegypti, has emerged as a global health issue. With the expansion of this mosquito to new geographical areas, driven by factors such as climate change, the need for preventive measures like using insect repellents has become critical. The present review explores the current state of the art on topical mosquito repellents, both synthetic and natural, used globally, especially in regions where dengue is endemic. Among synthetic repellents, DEET is the most widely used, supported by investigations demonstrating its efficacy and safety, although concerns about its toxicity exist in exceptional cases. Other compounds, such as picaridin, IR3535, and PMD are also common and offer alternatives with variable safety and efficacy profiles. Natural repellents, such as essential oils of citronella, lemon eucalyptus, and clove, have proven effective against Aedes aegypti. However, they present challenges due to rapid volatilization and the limited duration of their protective effect. To address these issues, combinations of essential oils and synthetic compounds have been proposed to improve efficacy and safety. Finally, the review highlights the complexity and the challenges of developing new repellents, including the high costs and lengthy timelines for commercialization, as well as the importance of continued research to improve the efficacy and safety of these products.

Chemical Compositions of the Marine Red Alga Laurencia composita Collected in Japan.

Marine red alga Laurencia composita was collected from seven sampling locations in Japan, and all samples were identified based on morphological studies as well as rbcL sequencing analysis. This is the first report of the isolation of (-)-8-bromo-9-hydroxy-(E)-γ-bisabolene (1) as a natural product, and bisabolene-type and β-chamigrene-type sesquiterpenes found in L. composita collected in Japan. In previous Japanese reports of L. composita, highly oxidized α-chamigrene-type sesquiterpenes were isolated as their major secondary metabolites. Therefore, these populations are the fissure chemical race in L. composita. All isolated compounds were tested their insect repellent activity against the adult maize weevil Sitophilus zeamais.

Preparation and Evaluation of Wound Healing Gel Using Extract of Psidium guajuva Leaves and Tridax Daisy Leaves

Wounds are physical injuries that results in an opening or breaking of the skin. Proper healing of wounds is very essential for the restoration of disrupted anatomical continuity and disturbed functional status of the skin. Wound healing is a complex but generally orderly process. Sequential waves of specialized cell types first clear the inciting injury and then progressively build the scaffolding to fill in any resulting defect. The antibacterial potential of the crude leaves extracts of Psidium guajava Linn. against some bacteria associated with surgical wound, burns, skin and soft tissue infections were investigated under different conditions. Tridax procumbens (L.) is a spreading annual herb found throughout India. The plant is a native of tropical America and naturalized in tropical Africa, Asia, and Australia. Local people known it as “Ghamara,” in English popularly called “coat buttons” and is dispensed for “Bhringraj” by some of the practitioners of Ayurveda. The plant has many pharmacological applications such as hepatoprotective activity, anti-infl ammatory, wound healing, anti-diabetic activity, hypotensive effect, immunomodulating property, bronchial catarrh, dysentery, and diarrhea and to prevent falling of hair promotes the growth of hair, and antimicrobial activity against both Gram-positive and Gram-negative bacteria. The leaf juice possesses antiseptic, insecticidal and parasiticidal properties, as a remedy against conjunctivitis and is used also to check hemorrhage from cuts, bruises and wounds insect repellent. Keywords: Preparation, Evaluation, pharmacological effect, Wound Healing Gel, Antiseptic.

Repellency of Essential Oils and Plant-Derived Compounds Against Aedes aegypti Mosquitoes.

Plant-based oils have a long history of use as insect repellents. In an earlier study, we showed that in a 10% concentration, geraniol, 2-phenylethl propionate, and the plant-based essential oils clove and cinnamon effectively protected from mosquito bites for over 60 min. To expand on this study, we reanalyzed our GC-MS data to identify the short organic constituents of these oils. We then used an arm-in-cage assay to test the repellency of different concentrations and combinations of these oils and pure compounds. We found a sigmoidal relationship between the complete protection time from mosquito bites and the concentration of these oils. The complete protection times we recorded for combinations of these oils suggest an absence of additive effects. The results of this study can inform the development of novel, effective, and plant-based insect repellents.

KNOWLEDGE, ATTITUDE, AND PRACTICE (KAP) STUDY ON DENGUE FEVER IN ADULTS: AN ANALYSIS OF 200 PATIENTS

Background: Dengue fever (DF), a viral illness transmitted by mosquitoes, poses a growing public health threat, particularly in tropical and subtropical regions. This study seeks to assess the KAP of 200 adult patients concerning dengue fever in a densely populated urban environment. Methods: A cross-sectional survey was conducted among 200 adult patients diagnosed with dengue and admitted to the medical units of Hayatabad Medical Complex between January 2023 and December 2023. The data were analyzed using descriptive statistics with SPSS version 26, revealing notable gaps between the patients' knowledge and their preventive behaviors. Results: Most participants (85%) were aware that dengue is transmitted by mosquitoes, and 78% knew that Aedes aegypti is the main vector. However, fewer recognized key transmission details. Preventive measures were less commonly adopted, with 70% using mosquito repellents or nets, but only 45% eliminating standing water. There was a notable gap between knowledge and practice. Discussion: The findings show a gap between what people know and what they actually do to prevent dengue. The study highlights the need for better public health efforts, focusing on practical solutions and creating supportive environments to encourage community-wide adoption of preventive measures. Conclusion: Despite adequate knowledge of dengue transmission and symptoms, preventive practices remain insufficient among adult patients. Public health strategies should focus on bridging this gap through community engagement and government-supported preventive measures.

Exploring the efficacy of Citrus medica leaf extracts as a natural mosquito repellent: Implications for sustainable mosquito-borne disease control

Exploring the efficacy of Citrus medica leaf extracts as a natural mosquito repellent: Implications for sustainable mosquito-borne disease control

ANALYSES AND DETERMINATION OF THE CHEMICAL COMPOSITIONS OF MOSQUITO REPELLANTS SOLD IN IMO STATE, NIGERIA – INDICATING THEIR LEVELS OF ECO-FRIENDLINESS AND TOXICITY

A lot of persons make use of mosquito repellants in order to be free of mosquito bites irrespective of the aftereffects of these repellants. More serious illnesses other than those infected by mosquitoes seem to arise from some of these repellants. In this research, the chemical composition and safety profile of various chemically synthesized mosquito repellants commonly used in Imo State, Nigeria were carried out. X-ray fluorescence was done to find out the elements present in each. GC-MS analyses were carried out to identify the organic compounds while the ADMET (toxicity) test was followed to evaluate the level of toxicity in each repellant. From the GC-MS analyses, it was deduced that six of the ten types of repellants analyzed contain a non-friendly compound generally known as DEET (Diethyltoluamide). These are medi soft cream with 3.567% of DEET, gardia cream = 22.544%, fly killing bait powder = 7.602%, Rambo coil = 2.822%, reptogel cream = 7.972% and super kill coil = 0.094% all by mass. X-ray done indicated the presence of lead, a harmful element though found at a low concentration in medi soft cream, super kill coil, Swan Green coil, Rambo paper, Rambo coil, odomos cream and fly killing bait powder. Sulphur too detected in Rambo powder, Rambo coil and reptogel cream seems not threatening. Considering the ADMET test, it reveals that most of these repellant are not safe especially when applied for long as each of their prediction toxicity does not correspond to a manageable extent to the DrugBank% database. Odomos cream with no DEET and no elemental sulphur may be less toxic as its toxicity prediction tallies more with the DrugBank% data base. This research therefore recommends that the use of chemical mosquito repellants be discouraged till the producers get back to the drawing board. Natural repellants could be resorted to.

REVIEW: PLANTS WITH REPELLENT ACTIVITY

Mosquitoes are vectors of illnesses, such as encephalitis, dengue, filariasis, intestinal sickness, and encephalitis. These diseases have become epidemics in Indonesia and around the world. Natural repellents are alternatives for preventing mosquito-borne diseases that are safe, easily degradable, and eco-friendly. This review aimed to identify compounds in plants with mosquito repellent activity. Data were obtained from national and international journals using search platforms, including PubMed, Scholar, SciDirect, and Hindawi. This review focuses on plants with repellent activity, their resulting repellent activity, the content of bioactive compounds, and the mosquito species used. Many plants contain naturally occurring compounds that can repel mosquitoes. Following scientific research, 14 bioactive compounds have been shown to have repellent activity in plants. Keywords: repellent, volatile oil, mosquitos, bioactive compounds, narrative literature review

Mosquito control activities associated with dengue hemorrhagic fever in Indonesia: A literature review

Dengue Hemorrhagic Fever (DHF) is an endemic disease. It has become a public health concern. Mosquito control activities are needed to control vectors and prevent DHF. Therefore, we conduct a literature review of mosquito control activities associated with DHF in Indonesia. This study applies the selected articles using PRISMA (Preferred reporting items for systematic reviews and meta-analyses), and they are sourced from Science Direct, Google Scholar, Scopus, ProQuest, Ebscohost, and Portal Garuda. The criteria for the selected articles are full-text articles, published in 2015-2020, and those which are published in national journals SINTA 2 or international journals. This study reviewed 683 articles, out of which were selected for further examination. The key variables, such as draining water containers, covering water containers, burying and recycling used containers, using mosquito repellent, using larvacide , keeping larva-eating fish, having mosquito repellent plants, installing wire mesh on ventilation, showed significant correlation with Dengue Hemorrhagic Fever (DHF) incidence. Among the selected articles, 38.89% employed cross-sectional design, and the rest belonged to case-control studies. Most articles have variable draining water containers (55.56%), 50% covers water containers, 80% have a significant association between draining water containers and DHF incidence, and 66.67% have a significant association between covering water containers and DHF incidence. Most articles show that not implementing PSN (Pemberantasan sarang nyamuk) or PSN 3M (Pemberantasan sarang nyamuk, menguras, menutup, mengubur plus) is associated with the incidence of DHF and is a risk factor for the occurrence of DHF. On the other hand, the implementation of PSN or PSN 3M Plus will be a protective factor.

Liquid mosquito repellent induces toxic effects in zebrafish.

Mosquitoes serve as vectors for life-threatening parasitic diseases, presenting a continuous threat throughout human history. This has resulted in the extensive utilization of various mosquito repellents, including liquid mosquito repellents (LMRs), roll-ons, and topical creams. While these products demonstrate significant efficacy, the toxicological implications associated with their use are not yet fully understood and continue to be a subject of debate. The analysis conducted using gas chromatography-mass spectrometry (GC-MS) on LMR revealed the presence of 158 distinct compounds, among which were Piperazine 2,5-dimethyl propyl and a range of hydrocarbons. The analysis of network toxicology indicated that 78 of the examined compounds contravened Lipinski's rule of five and exhibited considerable overlap with target genes associated with lung cancer pathways, thereby highlighting potential concerns regarding their carcinogenic properties. The exposure of zebrafish embryos to LMR concentrations between 0.1 and 14 µg/mL resulted in developmental toxicity assays that demonstrated a dose-dependent escalation in mortality rates and the occurrence of morphological abnormalities, such as pericardial edema and skeletal deformities. Behavioral assays demonstrated a marked decrease in locomotor activity at elevated LMR concentrations, indicating potential neurotoxic effects. Biochemical analyses revealed elevated levels of reactive oxygen species (ROS), enhanced lipid peroxidation, and diminished glutathione, which are indicative of oxidative stress. Enzyme activity assays indicated a reduction in superoxide dismutase (SOD) and catalase (CAT) activities, alongside an increase in lactate dehydrogenase (LDH) activity, which suggests the occurrence of cellular damage. Analysis of gene expression demonstrated significant dysregulation in genes associated with oxidative stress (SOD1, CAT), inflammatory markers (TNF-α, IL-1β), apoptotic regulators (p53, bcl2), and neurobiological genes (brain-derived neurotrophic factor, bdnf). The results highlight the possible health hazards linked to LMR exposure, which manifest as developmental, biochemical, and genetic alterations in zebrafish embryos.

Symptoms of Residential Exposure to Insecticides and Associated Factors Among Young Thai Children in Urban Areas.

Household insecticide use may impact the health of young children in urban communities, but little is known about its acute effects. This cross-sectional study aimed to investigate the symptoms that may have been related to residential insecticide exposure and its associated factors in young children in urban areas. The study included 375 primary caregivers of children aged 6 months to 5 years from the Bangkok Metropolitan Region, Thailand, who had used insecticides in their homes within the past 6 months. An interviewer-administered questionnaire collected data on caregiver and child demographics, household insecticide use and exposure, child behaviors, and the history of child symptoms following insecticide use. The findings revealed that 9.6% of young children had experienced symptoms at some point during or after household insecticide use, with coughing (66.7%), skin rash/irritation (44.4%), and runny nose (25.0%) being the most common. The final logistic regression model using backward selection indicated that factors statistically significantly associated with symptoms included being a male child (OR = 3.38; 95% CI = 1.48-7.71), hand/object-to-mouth behaviors (OR = 2.69; 95% CI = 1.26-5.74), weekly use of insecticides (OR = 2.77; 95% CI = 1.22-6.26), use of insecticide chalk (OR = 3.64; 95% CI = 1.32-10.08), and use of mosquito repellent spray/lotion (OR = 2.51; 95% CI = 1.13-5.61). Additionally, the use of insecticide spray (OR = 2.72; 95% CI = 0.97-7.65), opening doors/windows for ventilation (OR = 0.46; 95% CI = 0.21-1.02), and consistently cleaning floors with a wet cloth after use (OR = 0.52; 95% CI = 0.24-1.11) were marginally associated. Residential exposure to household insecticides can lead to acute health effects, primarily respiratory symptoms, in young children in urban communities. Caregivers should be informed of these health risks to reduce children's exposure.

Socioeconomic, Demographic, and Behavioral Factors Associated with Dengue Outbreak: An Observational Study from Eastern Uttar Pradesh, India.

Background: Clinical and epidemiological aspects of dengue have extensively been studied in India. However, limited data are available on social and behavioral aspects of dengue outbreak. We aimed to fill this gap and wish to study socioeconomic, demographic, and behavioral factors associated with dengue outbreak in the Gorakhpur region of eastern Uttar Pradesh, India. Methods: This retrospective observational study was conducted among dengue patients discharged from hospital. Data on sociodemographic, economic, and behavioral factors of dengue were collected telephonically using a structured questionnaire. Continuous and categorical variables were reported as mean ± SD and numbers (%), respectively. Logistic regression analysis was done to establish association between patient's characteristics, awareness, and preventive behavior. Results: Age group 19-45 years 156/232, males 159/232, urban residents 142/232, residing in pucca house 187/232, and from lower-income families 149/232 were mostly affected in this outbreak. Patients spent a median of Indian national rupees 20,000 on treatment. Only 10.8% of patients had Ayushman health insurance cards. Awareness about dengue infection was found in∼43% patients. Literates, middle income group, and professionals/semiprofessionals were significantly more aware about dengue disease, mosquito bite, and treatment than their counterparts. Travel history was significantly associated with dengue infection in the males of 19-45 years age group belonging to rural areas. Use of mosquito repellent, nets, wearing full sleeve clothes were significantly less in rural residents while barefoot walking was more frequently observed in this population. Use of mosquito repellent was significantly associated with income, and these were observed more in the middle-income group. Conclusion: People with low education level, residing in urban areas, residing in pucca houses, who travel frequently, and who belong to lower-income groups were majorly affected by this dengue outbreak. Less dengue awareness and not following preventive practices were found in them. Targeted health education campaigns in urban setting could prevent dengue and economic burden on these vulnerable groups.

Effectiveness of Lime Leaves (Citrus aurantifolia) as a Natural Mosquito Repellent

The tropical climate gives rise to various kinds of tropical diseases, one of which can be caused by mosquitoes. The aim of this research was to determine the effectiveness concentration of lime leaf extract (Citrus aurantifolia) in repelling the Aedes aegypti mosquito. The research method used was an experiment by observing the effect of lime leaf extract as a natural mosquito repellent. Data processing used the one way anova statistical test, namely by using treatment plus 1 control in each treatment with 3 repetitions of the experiment. The results of this research were that there were differences in the treatment of orange leaf extract with a p-value (0.0005). The conclusion of the research is that the significant extract group is the 60 mg - 40 mg, 60 mg - 50 mg treatment, meaning that 60 mg of orange leaf extract treatment is the most effective as a natural insecticide.

Formulation of Mosquito Repellant Freshener Gel with China Grass as Gel Base and Lemon Grass Oil as Mosquito -Repellant

Background: Mosquitoes transmit severe diseases, including malaria, dengue, and Zika virus, necessitating effective mosquito repellents. While traditional repellents are typically sprays or lotions, these can be inconvenient and leave residues. A more convenient alternative is mosquito repellent gel, offering ease of application, lasting effects, and a more enjoyable user experience. This study focuses on a gel-based mosquito-repelling air freshener containing lemongrass oil, known for its mosquito-repelling properties and fresh citrus-like scent. Methodology: The study developed a mosquito repellent gel infused with lemongrass oil, containing active constituents such as neral, isoneral, and limonene. Sensory assessments evaluated the gel’s color and odor using 150 individual’s comments, and a hedonic test was conducted with 180 participants aged between 25-30 to assess product acceptability when applied to clothing and inanimate objects. To determine the longevity of the gel, total liquid evaporation was measured by weight loss over a four-week period, and the repellent's effectiveness was tested in a closed room. Results: Sensory assessment confirmed an acceptable color and a citrus-like odor for the gel, while the hedonic test indicated a favorable user response. Weight loss calculations demonstrated the gel's sustained presence over time. The closed-room test confirmed the gel's effectiveness in repelling mosquitoes. Conclusion: The lemongrass oil-based mosquito repellent gel is a promising alternative to traditional repellents, offering both user convenience and effective mosquito protection. Its long-lasting formula and positive sensory characteristics make it a viable option for personal and environmental use in mosquito-prone areas.

Enhanced Stability and Prolonged Insect-Repellent Action of Essential Oil-Loaded Nanostructured Lipid Carriers

Mosquito-borne diseases are a global health concern, necessitating effective and long-lasting insect repellents. This study investigated the physicochemical properties, stability, release kinetics, and efficacy of nanostructured lipid carriers (NLCs) and conventional emulsions (CEs) containing essential oils (NLC EOs) for insect-repellent applications. The droplet size of the CE was 18.46 ± 1.78 μm (Span 0.27 ± 0.06), while the NLC measured 136 ± 10.7 nm (PDI 0.26 ± 0.2) with a ζ-potential of –68 mV ± 2.2 mV (width 4.3 ± 0.1). EO incorporation did not significantly alter droplet size or ζ-potential. Gas chromatography–mass spectrometry confirmed an EO content of 8.57 ± 0.15 mg/mL in the CE EO and 7.75 ± 0.05 mg/mL in the NLC EO, with the NLC retaining a higher EO content over 90 days. Stability tests demonstrated consistent droplet sizes and ζ-potential for both formulations during storage. Release kinetics revealed diffusion-based release mechanisms, with the NLC providing a more sustained release than the CE. In a field test against mosquito species most frequently found in Greece, the NLC EO exhibited a significantly longer complete protection time (CPT) of 45 min, demonstrating more effective, long-lasting insect-repellent action. These findings revealed the NLC’s ability to retain volatile EO components efficiently, offering promising implications for long-lasting insect-repellent action.

Phytochemical Analysis of Dried Hevea brasiliensis (Will. Ex Adr. De Juss.) Muell. et Arg Leaves Collected from the Ovitrap with Mosquito Larvae

In the modern culture the paddy fields are converted into rubber plantations and its plays a good breeding source for mosquitoes especially during rainy seasons. Our present investigation is to find out the phytochemical constituents present in Hevea brasiliensis dried leaves collected from the ovitrap as a preliminary study to find out the mosquito repellent activity. The obtained result suggests that the control showed the presence of terpenoid, phenol, alkaloid and tannin. Similarly methanol extract showed the presence of phenol, tannin and steroid; chloroform extract showed the presence of terpenoid, flavonoid, tannin and steroid; acetone extract showed the presence of alkaloid, tannin, steroid and aminoacid and aqueous extract showed the presence of steroid and aminoacid. Moreover, the results suggest that the dried leaf collected from the ovitrap contains various phytoconstituents which can be utilized for industrial use.

Grapefruit-derived nootkatone potentiates GABAergic signaling and acts as a dual-action mosquito repellent and insecticide.

Humanity has long battled mosquitoes and the diseases they transmit-a struggle intensified by climate change and globalization, which have expanded mosquito ranges and the spread of associated diseases.1 Additionally, widespread insecticide resistance has reduced the efficacy of current control methods, necessitating new solutions.2,3 Nootkatone, a natural compound found in grapefruit, shows promise as both a mosquito repellent and an insecticide.4,5 However, its mechanism of action remains unclear. Our study demonstrates that nootkatone acts as a potent spatial and contact repellent against multiple mosquito species. Nootkatone-induced spatial aversion, which is influenced by human odor, is in Aedes aegypti partially mediated by Orco- and ionotropic receptor (IR)-positive neurons, while contact aversion is robust and likely mediated via the proboscis and independent of TRPA1 and IRs. We further find that nootkatone potentiates γ-aminobutyric acid (GABA)-mediated signaling by modulating the broadly expressed major insect GABA-gated chloride channel resistant to dieldrin (Rdl). At low doses, the chemosensory-mediated spatial and contact repellency is likely strengthened by nootkatone's disruption of synaptic transmission in select mosquito sensory neurons. At higher doses, nootkatone induces paralysis and death, presumably through broad-range synaptic transmission disruption. These findings reveal nootkatone's unique mode of action and highlight its potential as an effective mosquito control agent. Its dual role as a repellent and an insecticide, combined with low-to-no toxicity to humans and a pleasant smell, underscores nootkatone's promise as a future tool in mosquito control efforts.

Operational Risk Assessment Tool for Evaluating Leishmania infantum Introduction and Establishment in the United States through Dog Importation1.

International pet travel and commercial operations have increased animal disease importation risks, including for Leishmania infantum, a deadly parasite of humans and domestic dogs. Collaborating as an interdisciplinary working group, we developed an operational tool for veterinary and public health practitioners to assess and manage L. infantum risk in dogs imported to the United States. Overall risk varies by dog, human, and geographic factors but could be high without proper controls. We determined dog risk management strategies should include application of sand fly insecticides and repellents, sterilization, and treatment. US public health authorities can use a One Health approach to manage L. infantum importation risks via infected dogs.