Mosquito Repellent Activity of Various Formulations of Scent Leaf Essential Oil
Abstract
Mosquitoes are the most deadly vectors of parasites that causes diseases such as malaria, yellow fever, dengue fever and philleriasis, in view of the recent interest of developing plant based mosquito repellant on a replacement to the synthetic repellence. Hence, this study aimed at evaluating the mosquito repellent activity of O.gratissimum with the objective of accessing its incense, spray and cream formulation. The plant material used in this study was sourced from Akanu Ibiam Federal Polytechnic Unwana and processed into crude extracts for incense and spray and also extraction of oil for cream formulation. The mosquitoes used in this study was cultured from stagnant water kept in the lab. The evaluation of incense burning and spray of the crude extract was done using 5 different household for 3 consecutive days. The landing time and percentage repellency was done using mosquito cages containing 30 female blood starved mosquito. ODOMOS was used as standard, petroleum jelly and essential oil as the test and petroleum jelly alone as the control. Each evaluation was done for 10mins and all in triplicate. The results obtained showed 4hours and 2hours for incense burning and spray respectively. The landing time for DEET is 6 minutes, 1 minutes and 3minutes for standard, control and test and total bite of mosquito is 1, 26 and 12 for standard, control and test and repellency of 96.6% 13.3% and 60% respectively. The result showed that Ocimum gratissimum has significant mosquito repellency. Therefore, more research attention is being invoked towards harnessing the potential of using this plants extracts as a replacement for synthetic repellant.
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Introduction
1.1 Background of the Study Female mosquitoes are one of the most disturbing bloodsucking insects that afflicts human beings. They need blood meal in other to produce viable eggs that will hatch. Mosquito belongs to the family culcidea and order disptera (Ralph, 2008; Molavi; 2013). Mosquitoes are important primary host in the spread of malaria, yellow fever, and severe arboviral infections. Malaria which is caused by plasmodium parasites transmitted through the bites of female Anopheles mosquitoes continue to impact a major disease burden on infants and young children in endermic region (WHO 2014; and Chaiyakunapruk; 2011) in 2012, there were about 207 million cases of malaria and an estimated 627,100 deaths all around the globe. (WHO; 2014). Malaria is among the biggest public health issues globally, especially in tropical Africa, in which Nigeria suffers the world’sgreatest malaria burden, with approximately 51 million cases and 207,000 deaths reported annually (approximately 30%of total malaria burden in Africa). While 97% of the total population (Approximately, 173 million) is at risk of infection (WHO; 2014). Therefore, the control of mosquitoes and prevention of their bites are important public health concern around the world. One of the approach for control of these mosquito-borne diseases is the interruption of diseases transmission by either killing the mosquitoes or preventing them from biting individuals (Adeogun et al., 2012).
Mosquitoe repellents generally functions by hindering the capacity of the female mosquito to recognize the external stimuli (for example, carbon-dioxide water vapor, and heat) that she utilizes to spot a host (Pears; and Granshaw 2000). The mosquito and other insects repellent properties of NiN-diethyl-3-toluamide also known as DEET, were discovered as the first DEET product was introduced in 1956. Since it became commercially available, it has generally been regarded as safe. However, toxic effects have been recorded, including encephalopathy in children, urticarial syndrome, anaphylaxis, hypotension and decreased heart rate . an alternative to repel mosquitoes could be plant-based natural materials like plant oils to prevent the adverse effects of synthetic repellents. In comparison with synthetic repellents, they are deemed safe and good for the environment (Azeem et al., 2019).
Additionally, the use of chemical insecticide has been greatly impeded due to development of physiological resistance in the insects intermediary, environmental pollution resulting in bio-application of food chain contamination and harmful effects on beneficial non-target animals. However, people may be ignorant of the facts that overuse and injudicious application of such synthetic insecticides may result in resistance and unwanted toxic or lethal effects on a non-target organism as well as human and other environmental health challenges (WHO;2018).
This study therefore, aimed at determining the mosquitoes repellent activity of formations of scent leaf (ocimum gratissimum) essential oil in it various formulations.
