BACKGROUND: Dengue Fever (DF) and Dengue Hemorrhagic Fever (DHF) are now considered as major health problems in the Philippines. N,N,-dietyl-3-toluamide (DEET) is recognized as the most effective against Aedes aegypti. However, the concern about its use have underscored the need to find a safer alternative repellent.
OBJECTIVES: This study aims to determine and compare the repellent activity of tea tree (Melaleuca alternifolia) oil against Aedes aegypti with 7% DEET using a double-blind controlled experimental trial
METHODOLOGY: Twenty healthy subjects were allocated systematically by alternate assignment into three treatment groups (Control vs. Tea Tree oil, control vs. 7 percent DEET, Tea Tree oil vs DEET). All subjects were exposed to Aedes aegypti for 5 minutes every hour for 8 hours and the number of mosquitoes biting/landing were recorded and compared for each treatment group
RESULTS: Fifty percent tea tree oil has a repellent activity against Aedes aegypti and its efficacy is comparable to 7% DEET. Both treatments were equally effective in repelling mosquitoes for 7 hours. No cutaneous reactions to both repellents were noted
CONCLUSION: The efficacy of tea tree oil is comparable to 7% DEET and is recommended as an alternative natural mosquito repellent.

Human ; Aedes ; Deet ; Dengue ; Healthy Volunteers ; Insect Repellents ; Melaleuca ; Severe Dengue ; Tea ; Tea Tree Oil ; Trees

We reported a previously healthy 25-year-old female patient who developed hypersensitivity pneumonitis following repeated exposures to the smoke of mosquito coils. The patient presented with vague symptoms of cough and fever for 3 days. Diagnostic criteria proposed for clinical use in this case included history, exposure to a recognized antigen, physical examination, consistent radiographic images, bronchoalveolar lavage and lung biopsy. Much symptomatic relief and better radiographic response were noted after short-term use of oral corticosteroid and removal of the offending antigen.
Adult ; Alveolitis, Extrinsic Allergic ; diagnosis ; etiology ; Female ; Humans ; Insect Repellents ; adverse effects ; Mosquito Control ; methods ; Smoke ; adverse effects

OBJECTIVETo assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant, Mentha piperita (M. piperita) against the larval and adult stages of Aedes aegypti (Ae. Aegypti).

METHODSThe larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae. aegypti using WHO protocol. The mortality counts were made after 24 and 48 h, and LC50 and LC90 values were calculated. The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique. The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol. The mosquito bites on both the arms were recorded for 3 min after every 15 min. The experiment continued for 3 h and the percent protection was calculated.

RESULTSThe essential oil extracted from M. piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC50 and LC90 value of 111.9 and 295.18 ppm, respectively after 24 h of exposure. The toxicity of the oil increased 11.8% when the larvae were exposed to the oil for 48 h. The remarkable repellent properties of M. piperita essential oil were established against adults Ae. aegypti. The application of oil resulted in 100% protection till 150 min. After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm.

CONCLUSIONSThe peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide, oviposition deterrent and ovicidal agent. The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.

Aedes ; drug effects ; growth & development ; Animals ; Insect Repellents ; pharmacology ; Insecticides ; pharmacology ; Larva ; drug effects ; growth & development ; Mentha piperita ; chemistry ; Mosquito Control ; methods ; Oils, Volatile ; pharmacology ; Plant Leaves ; chemistry ; Plant Oils ; pharmacology