INTRODUCTIONInfectious diseases carried by mosquitoes, especially in the setting of tropical climate nations, have generated a wide interest in insect-repellent research and development. The most noteworthy and alarming of all mosquito-carried infectious diseases is dengue, which has been described as the most important insect-borne viral disease in tropical areas worldwide. (Dussart et al., 2012) Dengue is therefore considered to be a foremost priority in scientific research and development in the field of infectious medicine. However, Behura et al. (2011) point out that no existing and definitive cure for dengue actually exists, with mosquito control being the only main and viable method of disease prevention. Tens of thousands of people nationwide fall sick to insect-carried infectious diseases, particular kinds of which are severe enough to cause death or serious injury.
In the Philippines alone, 69,297 cases of dengue fever, the potentially lethal disease carried by mosquitoes, were reported by the Department of Health in 2016. And of these 69,297 cases, 334 fatalities were recorded in official government statistics. (DOH, 2017) In a worldwide setting, the World Health Organization (2014) estimated 50-100 million infections of insect-borne diseases every year, with at least 500,000 of those cases being dengue cases.
With these numbers on the rise all over the world, efforts to curb insect-borne diseases are now being funded and looked into further by international health institutions and research companies. Wong et al. (2015) explain that having dirty surroundings and areas in local communities is a primary cause of the breeding of mosquitoes as well as the diseases they carry, which is particularly the case in densely populated areas with low socioeconomic standing. With poorer standards for cleanliness and sanitation, infectious diseases breed and spread quicker and more effectively. The researchers elaborate that primary prevention of insect-borne and particularly mosquito-borne diseases such as dengue is achieved by using mosquito repellents, mosquito coils, preventive clothing, removing sources of stagnant water, and other methods. In total however, it was concluded that more efforts should be done in order to develop effective strategies for containing dengue, with focus on proper education and increasing public knowledge on the matter. (Wong et al., 2015)The dengue problem is already a widely known insect-borne infectious disease with potentially lethal implications.
Wong et al. (2015) confirm that the general public is already informed and educated on the basic information about the dengue virus, as well as simple prevention practices in order to avoid contraction. However even with basic education and information dissemination in place, communities, particularly those of low socioeconomic standing, were still found to have insufficient garbage collection and water supply, perfect for the breeding of Aedes mosquitoes.
These findings by Barreto et al. (2008) were noted to be indicative of the fact that both public education efforts and dengue mitigation procedures are not fully effective. Current and popular dengue prevention practices include using mosquito repellents, mosquito bed nets, mosquito coils, protective clothing and the regular removal of sources of stagnant water in order to minimize areas where mosquitoes can breed (Naing et al.
, 2011). Wong et al. (2015) found that the aforementioned prevention practices were more effectively and prevalently enforced in rural areas and communities. Urban populations with skilled professionals were also found to be less likely to undertake dengue prevention practices compared to the unemployed. These findings are further supported by Al-Dubai et al.
(2013), who found that people belonging to the 31-40-year-old age bracket were likely to have better dengue prevention practices that other age groups both above and below. With the collective findings that previous studies have been able to present, multiple implications can be brought forth for attention. What is of essence among these implications is that there truly exists a need easier and more effective solutions to the dengue problem. The previously mentioned study by Wong et al.
(2015) concluded that further action should be done in promoting active dengue prevention and control campaigns, especially in urban households and communities with middle to high income earners. The alternative to effective action, that is the maintenance of current dengue prevention efforts without further simplification or improvement, will only lead to even further rises to the dengue epidemic that the WHO (2015) estimated already reached a yearly figure of 50-100 million cases worldwide. A considerable amount of literature has been published on mosquito-borne diseases and the research, development and testing of commercial-grade mosquito repellents.
Studies point out that essential oils from plants such as andiroba, basil, catnip, cedar, citronella grass, clove, lemon-scented eucalyptus, garlic, geranium, neem, rosemary, and thyme function as substances that effectively repel mosquitoes (Campbell, 2009). This was further elaborated upon by Mala & Moore (2007), who explained that essential oils and extracts from plants that fall under the citronella genus are common components of plant-based repellents, particularly the species Cymbopogon nardus, which is in wide distribution in Europe and North America. Other investigations explored the situation and status of mosquito-borne viral diseases, particularly focusing on the dengue virus infection. Behura et al.
(2016) contended that the dengue virus represented a large obstacle in maintaining global public health. It was estimated that 2.5 billion people all over the world were at risk of contracting dengue and other related mosquito-borne diseases.
In the local Philippine setting, this was further supported by statistics from the Philippine Department of Health’s Epidemiology Bureau (2016) who reported that a total of 220,518 dengue cases were documented throughout the country from January 1st to December 31st, 2016. The numbers were found to be indicative of a 3.1% increase compared to 2015, the previous year of record. Further, the agency reported that highest concentrations of cases were reported from Regions 3, 4A, 6, 7 and 12.
With regard to dengue and mosquito-borne disease prevention, Wong et al. (2015) established that the primary procedures for prevention involved the use of mosquito repellents, bed nets, coils, protective clothing and the periodic removal of sources of stagnant or still water in order to minimize mosquito breeding. These were the suggested procedures in order to ensure the prevention and control of dengue and other related mosquito-borne diseases. As further support for these findings, the Hong Kong Government News (2017) urged the general public to make use of insect repellents and apply them on clothing and parts of the body that are exposed to mosquitoes, as advised by the Hong Kong Department of Health in order to bolster prevention against mosquito-borne diseases. Particular to the subject matter of this study, Anuar & Yusof (2016) found that the treatment of clothing with mosquito-repellent agents are an effective way of avoiding mosquito bites. The authors explained that a large majority of human skin is covered by garments and clothing, which if treated with mosquito repellents can effectively help avoid mosquitoes entirely, therefore giving the wearer protection and helping avoid exposure from mosquitoes and the diseases they carry. In order to effectively test repellent efficacy, Barnard & Xue (2007) established standard methods for testing mosquito repellent products. Of particular note is the “screened cage bioassay method”, wherein a 40 cm3 aluminum-frame cage is used, with a solid metal bottom and screen sides as well as acrylic sides for viewing.
The screened cage, which has a stockinette sleeve for access and testing, is meant to be used as a means to contain mosquitoes and expose them to substances safely in order to determine repellency. However, these studies have failed to recognize recent findings from other contemporary studies. Contrary to the aforementioned studies, Kongkaew et al.
(2011) found that citronella products were less effective mosquito repellents than DEET products in terms of the length of repellency time or protection. The authors added that the mixture of vanillin to the existing formula of citronella oil products could possible lengthen the amount of effective repellency time provided. In further contrast to the previous supporting studies, James (2004) contended that DEET products were more effective mosquito repellents than any other existing product, with DEET being a substance that is rapidly absorbed and found in common formulation contents ranging from %% all the way to 100%. Extensive research and development on DEET and essential oil based products as mosquito repellents currently exists. However, as of present time no definite product directly makes use of citronella essential oil in combination with commercial-grade garment treatment products to provide mosquito repellency to treated clothing. As a result, there is no existing study or attempt that synthesizes the findings of numerous studies that came before into a tangible product or innovation. This therefore presents a unique, unexplored and unexploited opportunity to formulate an innovating project that can fill the large gap that exists as a result of the lack of studies and organized attempts. In filling this gap, both the scientific community and the real-world community have much to gain if an effective synthesized product can be formulated.
However, it is currently not clear whether the infusion mosquito-repellent citronella essential oils with commercial fabric softeners will lead to an effective product that provides mosquito repellency to treated clothing. The question remains if infusing fabric softeners with citronella oil will result in effective mosquito repellency or not. The exact quantities and compositions, as well as the exact efficacy of such a combination is not currently known and remains to be answered. Consequently, the research and innovation of citronella essential oil applications to include infusion with garment treatments for mosquito repellency needs to be examined in greater detail.
Additional studies are needed in order to establish that the product is feasible, and it is therefore desirable for the testing of a synthesized fabric softener infused with citronella oil to be tested in a closed environment. With the findings from previous studies at hand, there is evidence that suggests an interesting possibility or correlation, calling the need for detailed testing and analysis. The aim of this paper is to study the efficacy of commercial-grade fabric softeners infused with citronella essential oil in repelling mosquitoes. If the naturally mosquito-repellent citronella essential oil (Campbell, 2009) can be infused into commercial fabric softeners in order to formulate a product that can effectively repel mosquitoes from treated clothing, then a product may be able to help and protect the more than 2.5 billion people worldwide that are at risk to mosquito-borne diseases such as the dengue virus.
This research examines the efficacy of citronella-infused fabric softeners in providing insect repellency to treated clothing. An experiment using commercial fabric softener will be infused with citronella essential oil in a determined amount, and then tested using the “Excito-Repellency Chamber Test” (Anuar & Yusof, 2016) to determine mosquito repellency. Utilizing bred local mosquitoes of the kind Aedes aegypti, multiple exposure trials will be conducted subjecting clothing treated with the experimental product to live mosquitoes contained inside the screened cage. Results will then be compared with a control group of clothing treated with regular commercial fabric softeners. Data will be assessed quantitatively, and the entire experimentation period will take 1 week in a dedicated enclosed area within a residential complex.