The mosquitoes belonged to the family of nematocer flies which was the Culicidae (from the Latin culex, genitive culicis, meaning "midge" or "midge"). The female mosquito was responsible for carrying the vector that leads to the spread of the disease. There were 3000 species of mosquitoes, but there were 3 primarily responsible for spreading disease to humans. First, the voracious Asian tiger, whose Aedes mosquito members carry yellow fever, dengue fever and encephalitis. Then, the malaria disease was carried by Anopheles mosquitoes. They also transmit filariasis (also called elephantiasis) and encephalitis. Finally, Culex mosquitoes carry encephalitis, filariasis and West Nile virus. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Recently, many cases related to mosquito diseases have spread globally. The Americas experienced a massive outbreak of the Zika virus (ZIKV) that affected at least 49 states in early 2013-2014. Although most cases have occurred in South America and the Caribbean, imported and indigenous cases have occurred in the United States. The vectors of ZIKV were known as Aedes aegypti and Aedes albopictus mosquitoes. Most people are unaware of the potential for ZIKV transmission by temperate Aedes mosquitoes. Aedes vexans is widespread worldwide, very abundant in some localities, bites humans aggressively, and is a competent vector of several arboviruses (Gendernalik, 2017). Zika was a viral disease transmitted by the bite of two species of infected mosquitoes and was an emerging disease. in the Western Hemisphere. People bitten by a mosquito infected with the Zika virus often have only minor or no symptoms. The main concerns related to Zika, however, include the virus's documented impact on pregnancies and sexual transmission of the virus. The other common mosquito disease that is now spreading worldwide is malaria. According to a report in the Herald, the country (Zimbabwe) has recorded a significant increase in malaria cases compared to the same period in the last two years, according to the Ministry of Health. Dr Mberkunashe said 119,593 cases were recorded in the first 11 weeks of this year, compared to 73,019 and 82,328 cases for the same periods in 2016 and 2015 (Mawonde, 2017). In May 2015, the first cases of locally transmitted infection were reported. of Zika received by the World Health Organization (WHO) from Brazil. Then, WHO received reports that mothers exposed to Zika during pregnancy resulted in microcephaly in babies in October 2015. As of February 2016, local transmission of Zika infection was reported in more than 20 countries, including the Americas, and an explosive number of thousands of cases were in Cape Verde, West Africa. (Kindhauser et al., 2016). Apart from that, based on the researchers from Kindhauser et al. (2016), serological tests (antibody detection) for Zika cross-react with antibodies stimulated by other viral infections, the presence of Zika virus was ideally confirmed by detection of viral nucleic acids by reaction test by polymerase chain reaction (PCR) or by virus isolation. . Plectranthus amboinicus (Lour.) Spreng was a perennial herb belonging to the Lamiaceae family, found in the tropics and warm regions of Africa, Asia and Australia (Arumugam et al., 2016). A big kind ofPlectranthus of the Lamiaceae family has 300 different species and can be found in tropical Africa, Asia and Australia (Lukhoba et al., 2006). This plant, also known as Indian borage, was a fleshy, succulent herb famous for its distinct oregano-like flavor and odor (Arumugam et al., 2016). IBO can be used as a food flavoring, food additive and natural non-toxic preservative (botanical fungicide) as a replacement for chemical fungicides.2.2.2 AdvantagesPlectranthus Amboinicus was a plant widely practiced as a medicinal herb.traditional medical specialty to treat diseases such as cough, fever and others. It was used in traditional medicine to treat conditions such as colds, asthma, constipation, headaches, coughs, fevers and skin diseases (Arumugam et al., 2016). Drawing on researcher Patel et.al (2010), he states that “the results show that the ethanolic and aqueous extracts of Plectranthus amboinicus had significant antioxidant activity”. Apart from this, (Manjamalai et al., 2012) found that Plectranthus Amboinicus essential oil exhibited substantial anti-inflammatory and antimicrobial action. Besides its medicinal properties, it also has antifungal, antiochratoxigenic and antioxidant activity to protect food products from microbes (Murthy et.al, 2008). Additionally, Plectranthus species were frequently used as medicines and were used to treat a range of illnesses, skin infections, digestive system problems, and respiratory problems (Lukhoba et al., 2006). The aromatic leaves of Plectranthus amboinicus (Lour.) Spreng can be used to make a syrup and researchers have proven that it can be used to treat cough and has also been used to treat livestock (Rice et.al , 2011). Plectranthus amboinicus was used for the treatment of skin ulcerations caused by Leishmania braziliensis in Brazil and the juice of this plant was used to treat skin allergies in India. It has also been used as a poultice for centipede and scorpion stings in Malay and to treat burns (Lukhoba et.al, 2005). Gurgel et.al (2009) cited that “we reported that P. amboinicus hydroalcoholic possesses promising anti-inflammatory and antitumor effects”. It may seem that Plectranthus amboinicus has many benefits for treating many diseases. 2.2.3 Bioactive Compound Bioactive compound was a type of chemical found in small amounts in plants and some foods (such as fruits, vegetables, nuts, oils, and whole grains). . Bioactive compounds have actions on the body that can promote good health. Previous studies have shown results in preventing cancer, heart disease and other illnesses (National Cancer Institute). Examples of bioactive compounds present in Plectranthus Amboinicus were such as carvacrol, thymol, Cis-Caryophyllene, t-Caryophyllene and p-Cymene. Furthermore, Arumugam et al. (2016) indicate that the main components of the aerial parts (stem and leaves) of P.amboinicus collected in Thailand were linalool (50.3%), carvacrol (14.3%), geranyl acetate (11, 7%) and nerol acetate (11.6%). with transcription factor inhibition activity. Additionally, the carvacrol constituent, along with other components such as p-cymene, b-caryophyllene, and a-terpinolene, were the bioactive compounds that might mediate the antifungal activity (Murthy et al., 2009). In Cuba, a leaf was boiled and given to patients suffering from chronic cough ortuberculosis and finally, scientific studies proved that P. amboinicus had anti-Mycobacterium tuberculosis activity. Additionally, unsterilized ethanolic extract of P. amboinicus leaves showed antibacterial activity against diabetic wound pathogens, S. aureus, P. mirabilis, E. coli, K. pneumonia, and P. aeruginosa (Arumugam et al., 2016). Therefore, it can be seen that the bioactive compound of this plant was very useful for medical benefits. 2.3 Essential Oil Extraction Many extractions were now widely used to extract the bioactive compound from the herbal plant. The researched bioactive compound was very important for medicinal purposes. Many of them have been installed to perform various types of important functions in living plants such as attraction, protection or signaling. The definition of bioactive compounds in plants was a secondary plant metabolite that exhibits pharmacological or toxicological effects in humans and animals (Azmir et al., 2013). The widely used extraction types to extract medicinal plant essential oil were such as hydrodistillation (Chen et. al, 2014), ultrasonic extraction (Wang and Lee, 2016), ultrasonic, microwave, Soxhlet extraction and cold maceration (Wu et al, 2015).2.4 Lotion formulation Extraction of essential oils from the herbal plant can be used to produce lotion, cream by adding it to a certain quantity. Bioactive compounds in Plectranthus Amboinicus such as thymol and carvacrol were important to promote as mosquito repellents for the skin. Many diseases have been proven to occur from mosquito bites such as Zika, dengue fever, encephalitis and yellow fever. Some mosquitoes were vectors of disease. This implies that they can transmit diseases from one human or animal to another. Typically, illnesses were caused by tiny parasites or viruses. For example, a mosquito that bites a human or infected creature can contract a virus with the blood meal and spread to other people through its bites. The higher amount of carvacrol and thymol as bioactive compound in Plectranthus Amboinicus essential oils may cause the cases of mosquito-borne diseases decreased. The small amount of Plectranthus Amboinicus essential oil extract was used in the formulation of the lotion as an active ingredient to promote the lotion as an insect repellent lotion. The basic components to form a lotion or cream were a thickener, emulsifier, humectant, diluent, emollient and others. The objective of this work is to optimize the formulation of an anti-mosquito lotion from the essential oil extract of Plectranthus Amboinicus leaves by varying the emulsifier, thickener and essential oil. Table 2.4.1 presents the different types of thickeners used in industry today. From the table, the appropriate thickener to use in the lotion formulation was a synthetic thickener such as carbopol. From Table 2.4.5, the appropriate emulsifier used in this formulation was an oil-in-water emulsifier such as glyceryl monostearate. The oil-in-water emulsifier was suitable for lotion formulation because the texture of the lotion was too non-greasy mixture and the emulsifier function was supported by the oil drops packed in water, used for effects moisturizers. The selection of the emulsifier was based on the calculation of HLB (hydrophilic-lipophilic balance). Lipid Thickeners Lipid thickeners were mainly made of liquefied materials. They deliver their thickness.