The Use Of Squamosa In Preventing Mosquito-Borne Illnesses
In year 2016, the Department of Health (DOH) declared mosquitoes, specifically the Aedes aegypti, as the number one public health enemy of Filipinos for causing illnesses such as dengue, chikungunya and Zika virus. This phenomenal outbreak led to numerous cases of hospitalization and severe dengue manifestation which resulted in risk in environmental factors and inconsistent preventive practices aside from urbanization, poor solid waste management, increasing population, inadequate public health infrastructure, and lack of an effective mosquito surveillance system. This complication paved way to a constant need to innovate ways that prohibits the growth of mosquito-borne diseases in the Philippines.
The use of pyrethrin-based liquid formulations, pesticides found naturally in chrysanthemum flowers, are one of the most common and conventional methods of controlling mosquitoes which is also a common ingredient of insect and bug sprays used commercially. However, as pyrethroids (synthetic pyrethrin) are increasingly used as substitutes, prolonged exposure to these chemicals could lead to local irritation, severe allergic dermatitis and systemic allergic reactions. Large amounts of these chemicals could also cause nausea, vomiting and headache. Aside from human health concerns, unrestrained use of synthetic chemicals has also resulted in an increase in resistance of insects toward conventional insecticides as well as effects on non-target organisms such as environmental and food contamination.
These drawbacks of commercial insect repellants led to a search for bio-insecticides, a naturally occurring substance, which could be used as substitutes for synthetic insecticides in bioactive compounds that are eco-friendly and nontoxic. Annona squamosa L. (Annonaceae), commonly known as custard apple or star sop in some places, is a multipurpose tree with edible fruits and a source of medicinal and industrial products. It has insecticidal and antihelminthic properties as well as anti-microbial, anti-insecticidal, anti-fertility, and antiulcer properties. Various extracts of A. squamosa leaves are known to contain flavonoids, an allelochemical considered as a potential natural insecticides for mosquito management, which operates as phytoalexins as a response to abiotic and biotic stress. This poses a significant insecticidal property of A. squamosa.
The use of plant products on various aspects of life has long been practiced since the ancient times. However, due to the increase of chemical products developed, specifically as insecticides and similar others, the use of natural products against pests were overshadowed by this escalation. Over the course of years, the public became more aware of the ingredients and chemicals that consists the products they are patronizing as well as the release of studies that proposes the use of these chemicals as costlier and poses a residual toxicity to livestock and humans. Aside from this, the growing dilemma of insect resistance towards chemical-based insecticides revived the interest of the insecticidal and insect repellent potential of plants.
Mosquito repellent candle
Previous studies introduced botanical insecticides that offered a more natural and environmental friendly approach to insect control compared to commercial synthetic insecticides. Among these various family of plants that is believed to have possessed insecticidal properties is the Annonaceae where the species Annona squamosa or sugar apple belongs. Leaf extracts of A. squamosa have shown potentiality for pest control against a range of insect pests like butterflies and moths, ticks, beetles, and similar other insects. Various types of flavonoids in A. squamosa that acts as phytoalexins are also observed by previous researches.
Squamosa leaf extracts may prove more useful in tropical countries where the plants are usually common. Paraffin wax is a white, tasteless, odorless solid derived from petroleum, coal or oil shale. According to National Candle Association (NCA), waxes are hydrocarbons that originated from animal, vegetable, or plant but their chemical composition are similar and burn in the same manner. Furthermore it was emphasized that no specific blend of wax is best for candle making and that candles burn cleanly and safely when provided with high-quality format. Hence, the use of paraffin wax mixed with A. squamosa leaf extract is used as an ingredient to create a mosquito repellent candle.
Protection against mosquitoes
A survey conducted by the World Health Organization stated in a study by Bagum et al. (2013), 80% of populations living in the developing countries almost rely on traditional medicine for their primary health care needs and pest control. This holds true for the Philippines as it has reached a level of serious implications of mosquito infestations that have caused numerous cases of severe dengue, chikungunya, and Zika virus which are more common in areas with poor sanitation and low protection against the spread of mosquito-borne diseases. However, for these people, commercial products that protect them against these insects are becoming more expensive for daily use. Other than these products, the safety of the use of mosquito repellents is also in question. In this case, it is essential for people to look for convenient and affordable mosquito repellents yet just as effective and safe as those produced commercially. This led to mosquito candles that uses natural ingredients and fits well on the certain criteria. Most of the research studies found similar effects of insecticidal and insect repellent property of A. squamosa as a promising candidate for bio-insecticides.
While there were studies that utilized the use of A. squamosa leaves, they were not clearly as numerous as the ones that utilized other parts of the plant such as seeds, fruit and bark. For the data gathering and analysis, the methods of most studies are experimental and observational that may have been limiting the use of the insect repellent in an actual scenario and the actual observation of an existing area infested with mosquitoes. Another gap was the use of natural mosquito candles that are some of the new and innovative ways of repelling insect easily without interfering with the daily activities of the participants.
