1.1 INTRODUCTION
Malaria is one of the commonest and
major parasitic infections of public health interest in the globe
especially in the tropics and sub-tropics. It still remains the
principal cause of morbidity and mortality in all sub-saharan countries
up to this day. Malaria accounts for 10% - 30% of all hospital
admissions, and is responsible for 15% - 25% of all deaths in children
under the age of 5 years. Pregnant women are not be exonerated from the
risk of malaria infections as the disease is also said to be responsible
for a substantial number of miscarriages and underweight births (WHO,
1996; RMB, 2007). Globally, only mosquitoes of the genus Anopheles have
been incriminated as the vectors of this life-threatening disease.
Therefore the control of malaria invariably implies sustainable control
of its vectors.
One of the best control measures is the
application of intervention methods. Such intervention methods involve
the use of insecticides, larvicides, topical repellents among others, to
intercept the vector-host interactions or contact. Cutting off or
breaking the link between mosquito vectors and human hosts consequently
disrupts the life cycle of malaria parasite. The overall result is the
reduction in morbidity and mortality rates following reduced
transmission of the disease (Toure, 2002). Beside from the use of
insecticide treated nets (ITNS), many other different types of
substances, natural and synthetic, have been discovered and adopted to
protect human hosts against mosquito bites. These substances keep
mosquitoes from biting humans and make human hosts undetectable, or are
anti-mosquito cloak that conceal or hide the host from recognition by
mosquitoes, as a meal source (Jacobson, 1990; Foster and Duke, 1990;
ICMR, 2003). Today citrus essential oils as well as extracts from other
plants such as Cedar wood, Citronella, Eucalyptus, Pennyxoyai,
Turpentine, Winter green (Sadik, 1973), have been identified as very
important natural resource of either pesticides or insecticides
(Raguraman and Singh, 1997; Gbolade, 2001), or repellent (Sadik, 1973;
Thorsell et al., 1998; Oyedele et al., 2000; Govere et al., 2000;
Girgenti and Suss, 2003). They have been used as both topical
preparations and combustible products like incense sticks to repel
insects such as mosquitoes.
In some places, dried citrus fruit
peels are burnt on charcoal fire to repel and/or destroy mosquitoes in
homes.The global preference of phytochemicals in malaria vector control
may be based on their unique properties which include environmental
sustainability, easily biodegradable, readily available and cheap
andnon-toxicity to man and his domestic animals (Herrera and Vieto,
1980; Duke, 1992). Repellent and attractant properties of phytochemicals
from plants other than citrus plant species have been investigated by
various scholars (Tyagi et al., 1994; Ansari and Razdam, 1995; Trigg,
1996; Pathak et al., 2000; Moore et al., 2002).
Mosquitoe insecticides are quick and
powerful way to get rid of mosquitoes but unfortunately they are only
temporary. The effect usually lasts only as long as the insecticide is
present, as soon as it drift away or dries out, the mosquitoes are back.
Mosquitoes control officials use insecticides only in combination with
other form of mosquito control. The same method should apply to use
around the house. Insecticides are not long-term solution. Insecticides
are commonly dispersed through a fog or ultralow volume mist.
Insecticides are available at most home and garden stores, and it come
in hand- held applicator or devices that can be attached to a lawn
mower. Example of two popular insecticides are Malathion and Permethrin.
Malathion is an organophosphate often
used to treat crops against a wide array of insects. It can be sprayed
directly onto vegetation such as bushes where mosquitoes like to rest,
or used in a 5% solution to fog in the yard. In small amount used for
mosquito control , it poses no threat to humans or wide life. In fact,
Malathion is also used to kill headlice.
Permethrin is one of the group of
chemicals called Pyrethroids. It is a synthetic form of a natural
insecticides found in Chrysanthemus flowers. It usually mixed with oil
or water and applied as a mist about 1/100th of a pond per acre. Like
Marathion, permethrin kills mosquitoes by disrupting their nervous
systems. Not harmful to humans and animals in small quantity, but toxic
to fishes and bees.
Both Malathion and permethrin are also
available in sprays for use inside the home. The insecticides works for
several days when applied to shrubbery or grass, but will breakdown
overtime, especially in rain. When released into air through fog or
mist. They are usually good for few hours before they become too
dissipated to be effective.
1.2. STATEMENT OF THE PROBLEM.
Over the years, mosquitoes pose a great
threat to humans' health. So, need arise to develop a lasting solution
to the invasion of mosquitoes in our environment. Different methods had
been detected to control mosquitoes but there is need to develop a
cheap, easy to produce, and long lasting solution.
1.3. OBJECTIVES OF THE STUDY.
The main objectives of the study is the
production of mosquito repellant insecticides using plant extracts which
will be cheap, effective and readily available for everyone even in
rural area.
1.4. RESEARCH QUESTIONS
1. What is an insecticides?
2. What is the effect of plants extract on mosquito?
3. Is mosquito repellant insecticides a lasting solution to mosquito invasion?
1.5. SIGNIFICANCE OF THE STUDY.
Overtime and repeated use of
insecticides resistance can occur in mosquito population. Scientists
researching the subject believe that the ability of mosquitoes to resist
insecticides represent a serious threat to the prevention of diseases
such as Malaria, dengue, Chikunginya. This threaten effort to prevent
epidermis.
Mosquitoes can be reduced or controlled
around our homes naturally through the use of natural or biological
means. Predatory fish (Gambusia), Dragonflies, plant repellant, bacteria
and even other mosquitoes that are mosquito eaters. Citrosa, Lemon
thyme, and Rosemary plants are known to be good insect repellant.
Bacillus Thurigiesis Israelensis is a Natural occurring bacteria used as
a larvacide in ponds and other areas where mosquitoes are breeding.
These are poisonous to mosquito larvae when they feed on it in the
water. Mosquito trap are also good method of controlling mosquitoes on
our area.Orange peel also known as Cestrum is a wonderful hybrid derived
from Cestrum diurnum and Cestrum Nocturnum. Cestrum is a veritable
living bouquet of pure orange blossoms that strives well in warm
climates. Orange peel is a fragrant orange flower, it need low
maintenance and strives in hot weather. Orange peel contains oil known
as Limonene oil which has a lethal effect on mosquito and some other
insects. Hence, Cestrum can be used as an active ingredient to produce
mosquito coil, which when ignited will repel mosquitoes within the limit
of the smoke.
1.6. SCOPE OF THE STUDY.
The research focus on the production of mosquito repellant insecticides using plant extracts.
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