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Mosquito vector management knowledge, attitude, practices and future of user & environment friendly new generation botanical Mosquitocide formulations: A review

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International Journal of Chemical Studies 2017; 5(3): 32-37
P-ISSN: 2349–8528
E-ISSN: 2321–4902
IJCS 2017; 5(3): 32-37
© 2017 JEZS
Received: 07-03-2017
Accepted: 08-04-2017
Dipak Kumar Hazra
AINP on Pesticide Residues,
Directorate of Research,
Department of Agricultural
Chemicals, Bidhan Chandra
Krishi Viswavidyalaya, Research
Complex Building, Kalyani,
Nadia, West Bengal, India
Arka Samanta
Research Scholar, Department of
Agricultural Entomology,
Faculty of Agriculture, Bidhan
Chandra Krishi Viswavidyalaya,
Mohanpur, Nadia, West Bengal,
India
Rajib Karmakar
AINP on Pesticide Residues,
Directorate of Research,
Department of Agricultural
Chemicals, Bidhan Chandra
Krishi Viswavidyalaya, Research
Complex Building, Kalyani,
Nadia, West Bengal, India
Koushik Sen
Research Scholar, Department of
Agricultural Entomology,
Faculty of Agriculture, Bidhan
Chandra Krishi Viswavidyalaya,
Mohanpur, Nadia, West Bengal,
India
Pratyusa Bakshi
Student (Master of Science),
Department of Agricultural
Extension, Faculty of
Agriculture, Bidhan Chandra
Krishi Viswavidyalaya,
Mohanpur, Nadia, West Bengal,
India
Correspondence
Arka Samanta
Research Scholar, Department of
Agricultural Entomology,
Faculty of Agriculture, Bidhan
Chandra Krishi Viswavidyalaya,
Mohanpur, Nadia, West Bengal,
India
Mosquito vector management knowledge, attitude,
practices and future of user & environment
friendly new generation botanical Mosquitocide
formulations: A review
Dipak Kumar Hazra, Arka Samanta, Rajib Karmakar, Koushik Sen and
Pratyusa Bakshi
Abstract
Every step taken to control the mosquitoes has a cumulative effect and contributes immensely to control
mosquito borne diseases. The eggs developing within the female mosquito need human blood for
nourishment and so the female mosquito bites humans. Protection of humans against mosquito bite by
using bed nets and mosquito repellent. By preventing water logging and destroying unwanted water
collections sources of egg laying can be denied and breeding of mosquitoes can be prevented. Most of
insecticides have effects on the human beings as well as the environment and other life forms. The real
benefits of botanical insecticides can be best realized in developing countries, where people may not be
able to afford synthetic insecticides, and the traditional use of plants and plant derivatives for protection
of mosquitoes is long established. Recently, attention has been paid to use user & environment friendly
new generation botanical mosquitocide formulations for protection against mosquitoes.
Keywords: Mosquito, vector, management, botanical mosquitocide, formulations
1. Introduction
Mosquitoes are among the most disturbing blood sucking insects afflicting human beings.
Several mosquito species belonging to genera Anopheles, Culex and Aedes are vectors for the
pathogens of various diseases like Dengue fever, Malaria, Yellow fever, Japanese Encephalitis
and several other infections. Mosquitoes alone transmit diseases to more than 700 million
people and over one million deaths are reported annually across the globe. Malaria which is
caused by Plasmodium parasites transmitted through the bites of female Anopheles mosquitoes
continues to impart a major disease burden on infants and young children in endemic regions
[1]
. The Aedes aegypti mosquito which spreads Dengue fever is responsible for more than 100
million infections worldwide every year, leading to thousands of deaths and more than 2.5
billion people or over 40% of the world’s population are now at risk of Dengue.
Having a mosquito infestation in close proximity to you and your family is an extremely
dangerous situation and can be fatal. The risk of mosquito-borne diseases is especially high in
humid areas. In the more arid regions of India, mosquito infestation commonly peak during
and after the annual monsoon rainfalls. In the more tropic and humid regions, the peak of
mosquito activity normally falls into the summers, when high temperatures fasten the
reproductive cycle of mosquitoes. Therefore, the control of mosquitoes is an important public
health concern around the world.
The use of synthetic adulticides for mosquito control is not advisable owing to environmental
hazards and prohibitive cost. Personal protection measures such as using mosquito nets or
synthetic repellents are not a practical solution in view of the socio-economic background of
the community and poor sustainability. The other approach is to eradicate immatures of
mosquitoes or to make the habitats unsuitable for mosquito breeding through environmental
modification/ manipulation. The latter may be considered as an environment friendly approach
but cannot be applicable to all the habitats in all situations. Though such source reduction is a
permanent solution for the prevention of mosquito breeding, it needs an engineering solution,
which involves huge expenditure.
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Therefore, botanical insecticidal operation considered to be a
user & environment friendly alternative measure of choice has
received adequate attention in recent times to keep people
safe from mosquitoes.
2. Types of mosquito problem
There are thousands of different species of mosquito, but the
most common mosquito problems in India are caused by-
2.1 Anopheles Mosquito
The development from egg to adult takes only between 6-10
days. The female lay between 60-150 eggs after a blood meal.
Anopheles mosquitoes commonly bite at night and rest
indoors and outdoors during the day. Anopheles mosquitoes
are transmitters of Malaria.
Fig. 1: Anopheles Mosquito
2.2 Culex Mosquito:
Culex mosquitoes are transmitters of Japanese B Encephalitis,
a very dangerous type of brain fever. They bite at night and
rest before and after blood meals. Culex breeds in polluted
stagnant water, and is a major pest problem in urban areas and
metropolises of India, where it breeds in drains.
Fig. 2: Culex Mosquito
2.3 Aedes Mosquito
Unlike above mentioned species, Aedes mosquitoes are active
during the day and they breed in clean water in man-made
containers, such as flower vases, water accumulation in tyres
and cans. In India, Aedes mosquitoes are responsible for
Chikungunya and Dengue. Their development from egg to
mosquito is quite rapid (6-8 days).
Fig. 3: Aedes Mosquito
3. Vector surveillance
3.1 Larval surveys:
For larval surveys, the basic sampling unit is the house or
premise, which is systematically searched for water holding
containers. Containers are examined for the presence of
mosquito larvae and pupae. Depending on the objective of the
survey, the search may be terminated as soon as larvae are
found, or it may be continued until all containers have been
examined. The collection of specimens for laboratory
examination is necessary to confirm the species.
3.2 Adult Surveys
3.2.1 Landing/biting collection
Landing/biting collections of humans is a sensitive means of
detecting low level infestations, but are very labour intensive.
Because adult males have low dispersal rates, their presence
can be a reliable indicator of clear proximity to hidden larvae
habitats. It is usually expressed in terms of landing/biting
counts per man hour.
3.2.2 Resting collection
During periods of inactivity, adult mosquitoes typically rest
indoors, especially in bedrooms and mostly in dark places,
such as cloth closets and other sheltered sites. Resting
collection requires systematic searching of these sites for
adult mosquitoes with the aid of flashlight. Following a
standard timed collection routine in selected rooms of each
house, densities are recorded as the number of adults per
house or number of adults per man hour of human efforts.
3.2.3 Oviposition traps
Ovitraps are devices used to detect the presence where the
population density is low and larval surveys are largely
unproductive as well as normal conditions. The ovitrap is
used for surveillance in urban areas to evaluate the impact of
adulticidal space spraying on adult female population.
4. Vector management
4.1 Environmental Management
The major environmental management methods used for
control of immature stages of vector are-
4.1.1 Environmental modification
The best way to avoid mosquito bites is to locate and remove
standing water where mosquitoes can lay eggs. Larvae are
usually found on the surface of stagnant water. Remove any
items located outdoors that can collect water, including
buckets, old tires, bottles, wheelbarrows, and cans. Keep
swimming pools circulating and chlorinated at all times.
Remove debris from rain gutters regularly and keep street
gutters clear to prevent water runoff from pooling.
4.1.2 Changes in human habitations
Efforts are made to reduce man-virus contact by mosquito
proofing of houses with screens on doors/windows
[2, 6]
.
Exclude mosquitoes from your home by keeping doors and
windows tightly shut or add screens with insect-proof netting.
Keeping fine mesh screens in good repair will maintain an
effective barrier
[7, 8]
.
4.2 Personal Protection
Protective clothing and repellents are common means of
personal protection against mosquitoes and other biting
insects
[3]
. Household insecticide products, namely, mosquito
coils, pyrethrum space spray and aerosols have been used
extensively for personal protection against mosquitoes.
Insecticide treated mosquito nets have limited utility in
dengue control, since the vector species bite during the day
time. However, insecticide treated bed nets can be effectively
used to protect infants and night workers while sleeping in
daytime
[19]
.
Mosquito nets act as physical barriers by blocking the vector
mosquitoes. Application of pyrethroid insecticides adds a
chemical barrier to the physical one, further reducing human–
vector contact and increasing the protective efficacy of the
mosquito nets
[18]
. Pyrethroid insecticides have a long residual
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action and low mammalian toxicity and provide prolonged
protection by their excito-repellent effect. As mosquitoes are
positively attracted by the odour of the sleeper inside the net,
these insecticides treated nets (ITNs) acts like a baited trap
and the mosquitoes that come into contact with the ITN are,
most often, killed
[18]
. Due to multiple effects, the ITNs have
been shown to avert around 50% of malaria cases and provide
at least double the protection than that provided by untreated
nets
[17, 18]
.
ITNs have been found to be the most cost-effective
interventions against malaria, and long-lasting insecticidal
nets LLINs were found to be significantly cheaper to use than
conventionally treated nets
[18]
. ITNs/LLINs are particularly
useful for high-risk populations that cannot be reached by
residual spraying, for people in forest-fringe areas who are at
risk of infection from forest stay, and for pregnant women
who are highly vulnerable to malaria
[18]
.
Conventional ITNs, treated with pyrethroids such as alpha-
cypermethrin, cyfluthrin, deltamethrin, lambda-cyhalothrin or
permethrin, need to be re-treated after three washes, or at least
once a year to ensure continued insecticidal effect. Long-
lasting insecticidal nets [LLINs] are factory-treated mosquito
nets, made with netting material that has the insecticide
incorporated within or bound around the fibers and the
insecticide is progressively released so that the net retains the
efficacy after repeated washings
[5]
. The LLINs are expected
to retain their effective biological activity without re-
treatment for at least 20 standard washes and for three years
of recommended use under field conditions. Permethrin (high
density polyethylene monofilament yarn blended with 2%
permethrin), Deltamethrin (multifilament polyester netting
treated with deltamethrin 55mgm
-2
), and alpha cypermethrin
(multifilament polyester netting treated with alpha
cypermethrin 200mgm
-2
) are used in LLINs
[5]
.
4.3 Biological Control
4.3.1 Mosquito-Eating Fish
One of the safest and interesting methods in mosquito control
is the use of biological agents that eat or destroy the larvae.
Several species of birds, bats, fish, spiders and predatory
insects also eat mosquitoes and will complement other control
methods. The Eco-friendly larvivorous top water minnow or
mosquito-eating fish, Gambusia affinis is an important control
agent for immature mosquitoes. It feeds on the larvae and is
most effective in ornamental ponds or other man-made bodies
of water that do not connect with natural waterways. These
fish can be introduced into all collections of potable water like
wells, tanks, ponds and lakes, particularly in rural and peri-
urban areas and in freshwater bodies in rural areas. Never
release mosquito-fish into streams, ponds or lakes as they can
become invasive. Gold fish and koi will also eat mosquito
larvae.
Fig.4: Mosquito-eating fish
4.3.2 Pathogens
Endotoxin-producing bacteria, Bacillus thuringiensis serotype
H-14 (Bt H-14) has been found an effective mosquito control
agent. Bacteria such as Bacillus sphaericus and Bacillus
thuringiensis varisraelensis are also effective larvicides.
However, they need to be re-introduced every 15 days and
their culture may need expertise. Mermitid Nematode
(Romanomermis culicivorax), Notonectid (Bug),
Ambylospora (Protozoa), Coelomomyces (Fungus), Nuclear
Polyhedrosis (Virus), and Cyclopoid copepods (Crustacean)
are the other biological larvicides found to be effective.
4.4 Chemical Control
There are many mosquito-control products sold to reduce
mosquito populations, including liquid, granular and powder
etc. formulations (Table 1). When using these chemical
products, take precautions to minimize human, pet, and
environmental exposure. Use of aerosol sprays, foggers and
misting systems is not recommended, due to the high
probability of harm during the application from inhaling the
pesticides and touching the residues they leave behind. People
and pets may be exposed to pesticides through direct contact
with spray droplets, contact with objects in the treatment area
on which residues have landed, or inhalation of aerosolized
pesticide in the air. Outdoor sprays can drift away and pose a
risk to non-target wildlife such as fish, honey bees, ladybugs,
and butter flies. These systems provide only temporary relief
from mosquitoes, and widespread use can lead to mosquito
resistance.
Table 1: List of registered larvicide/adulticide under the Insecticides Act, 1968, Government of India, (UPTO- 30.06.2016)
Insecticide Compound Formulation Group Larvicide /
Adulticide Dosage Uses
Alphamethrin 0.1 w/w (RTU) SP Adulticide 25-50 mg a.i./sq.m
Allethrin
0.5% Coil
SP
Adulticide
-
-
0.2% Coil -
4% Mat -
5% Aerosol -
3.6% LV -
Bifenthrin 0.05% Coil SP Adulticide - -
Cyfluthrin 10 % WP SP Adulticide 25-50 mg a.i./sq.m
100 gm of Cyfluthrin 10% WP to be diluted in 8
liters of potable water 40 gm of Cyfluthrin10% WP
to be diluted in 10% liters water
Chlorpyrifos M 40%EC OP Adulticide - -
Cyfluthrin 5% EW SP Adulticide 8 ml./ sq.m. -
Cyfluthrin +
Transfluthrin 0.025+0.04% SP Adulticide - -
Deltamethrin 2.5% Flow SP Adulticide 25 mg /sq.m For impregnation of polyester, nylon and cotton bed
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net
Diflubenzuron 2% Tab BU Larvicide 0.5-1.0 ppm ½- 1 Tablet in 40 lit. water
25% WP 25-50 g a.i./ha -
Deltamethrin+Allethrin 0.05+0.04% SP Adulticide 12.5-25 -
Deltamethrin +
D-transallethrin 2.5+2% EC SP Adulticide 12.5-25 -
Diazinon 25% CS OP Adulticide - -
D-transallethrin 2% MAT SP
Adulticide
- -
0.1% Coil -
D-allethrin 21.97% Mat SP Adulticide - -
Fenthion 2% Spray OP Adulticide -
Lambda Cyhalothrin 2.43% CS SP Adulticide 10mg a.i./sq.m Impregnation of bed nets to prevent attack from
mosquitoes.
2.43% CS 20-30 mg/sq.m. -
Malathion 2% Spray OP Adulticide - -
Metofluthrin 0.005% Coil SP Adulticide - -
Permethrin 2% w/w SP Adulticide -
For control of mosquitoes both indoors and
outdoors. After unpacking and before using the new
b
ed net, keep it in and open place for 12 hours away
from the sunlight
Proteamphos 1% Spray OP Adulticide - -
Propoxur+Cylin 0.75+0.025 Aero Carbamate
/ SP Adulticide - -
Propoxur 20%EC Carbamate Adulticide 200mg a.i./sq.m -
Pirimiphos-methyl 1% Spray OP Adulticide 50 ml/100m3 -
Pyrethrin+Malathion 0.05+1% SP/OP Adulticide - -
Pyrethrin 0.2% w/w SP Adulticide - -
Propoxur 1% Spray Carbamate Adulticide - -
Prallethrin
1% w/w Red Mat
SP Adulticide
-
-
0.04% Coil -
0.8% w/w Mat -
0.5% Coil -
1.2% Mat -
19% w/w VP -
2.4% w/w Liq. -
S-Bioallethrin 2.4% Mat SP Adulticide - -
Transfluthrin
0.88,1.6% liq. Vap.
SP Adulticide
-
-
1.6% liq. Vap. -
20% w/w MV Gel -
0.03% w/w Coil -
1% EU - It is used for controlling/repelling adult mosquitoes
in the houses (effective for 6 hours)
1.2% liq. Vap. - -
SP= Synthetic Pyrethroids; OP= Organophosphorus; BU= Benzyl Urea.
4.4.1 Larvicide
All the larvicides, which are safe, without any odour or
colour, have residual effect with low mammalian toxicity and
do not pose any health hazard should be used. Temephos, an
organophosphate compound meets all the above mentioned
requirements and this insecticide is being used under the
public health programme. The recommended dose for
application of Temephos (50 EC) is 1 ppm (1 mg per liter of
water). Themiphos and Fenthion are the two commonly used
larvicidal agents. Themiphos is used on potable water
collections and Fenthion, being more toxic, is used on non-
potable water collections. Oils may be applied to the water
surface, suffocating the larvae and pupae. Most oils in use
today are rapidly biodegraded. An insect growth regulator
such as methroprene is specific to mosquitoes and can be
applied in the same way as chemical insecticides.
4.4.2 Adulticide
The following methods are recommended for the control of
adult mosquitoes:
4.4.2.1 Pyrethrum spray
It may be used in indoor situations as space spray at a
concentration of 0.1% - 0.2% @ 30-60 ml/1000 cu. ft.
Commercial formulation of 2% pyrethrum extract is diluted
with kerosene in the ratio of one part of 2% pyrethrum extract
with 19 parts of kerosene (volume/volume). Thus, one liter of
2% pyrethrum extract is diluted by kerosene into 20 liters to
make 0.1% pyrethrum formulation (ready-to-spray
formulation). After dilution, pyrethrum extract is sprayed with
Flit pump or hand operated fogging machine fitted with micro
discharge nozzle.
4.4.2.2 Malathion fogging or Ultra Low Volume (ULV)
spray
In application of ULV, minimum volume of liquid insecticide
formulation is applied per unit area. That is, the insecticide is
broken down into small droplets of a volume median diameter
(VMD) of 40-80 microns with an objective of producing a
cloud of insecticide droplets that remain suspended in air for
an appreciable time and driven under the influence of wind
[20]. This provides maximum effectiveness against target
vectors. Since no diluent is used, the technique is more cost-
effective than thermal fogging but it does not generate a
visible fog. Most organophosphorus insecticides in their
technical form can be applied as ULV spray. Under the public
health programme, ULV spray (fogging) is undertaken by
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using 95% or pure technical malathion. The ground
equipment mostly used for ULV spray includes portable
motorized knapsack blowers and cold aerosol generators.
4.4.3 Indoor Residual Spraying (IRS)
IRS is an integral component of the global mosquito control
plan and currently DDT, pyrethroids (Deltamethrin 2.5% WP,
Cyfluthrin 10% WP, Alpha cypermethrin 5% WP and
Lambda cyhalothrin 10% WP) or Malathion 25% are used in
different parts of the world for this purpose
[12]
. All the
interior walls and ceilings as well as the underside of
furniture, back of the doors and porches of permanent human
dwellings as well as Jhoom huts where people sleep during
the plantation or harvesting season are sprayed. For protection
during the entire transmission season, two rounds of DDT or
synthetic pyrethroids or three rounds of Malathion are used
[16]
.
4.4.4 Mosquito Repellents
Mosquito repellent is a substance applied to skin, clothing or
other surfaces which discourages mosquitoes from landing or
climbing on that surface. Usually, mosquito repellents work
by masking human scent or by using a scent which
mosquitoes naturally avoid
[4]
. Carbon dioxide and lactic acid
present in sweat in warm-blooded animals act as an attractive
substance for mosquitoes. The perception of the odour is
through chemo-receptors which are present in the antennae of
mosquitoes. The repellents block the lactic acid receptors and
destroy upwind flight. Therefore, mosquitoes lose its contact
with the host. The advantage of skin repellents is their relative
cheapness. Most of the insect repellent cream being produced
by different manufacturers are chemical based and may cause
skin problems to human being on prolonged use. DEET spray
is still the most widely used mosquito repellent. It has
generally been regarded as safe. However, toxic effects have
been recorded, including encephalopathy in children, urticaria
syndrome, anaphylaxis, hypotension and decreased heart rate
[1]
. Several other compounds have been evaluated for repellent
activity, but none has had the commercial success of DEET.
5. User & environment friendly botanical formulations
5.1 Spreading Oil Formulations
The surface-spreading formulations are essential oil-based
formulations which can be applied by dropping on water
surface, and after application, the formulation spreads to the
whole water surface within a few seconds (Fig. 5). Basically
these formulations are stable dispersion of water-insoluble
liquid or solid in oil, and if it is a solid dispersion, the
dispersed particles are wet, grinded into a fine particle
suspension and stabilized with the help of wetting and
dispersing agents. When these formulations are applied on the
water surface, the active ingredient maintains a smooth
networking film on the water surface. The films formed by
these formulations are not continuous films but having holes
which maintain the required oxygen level within the water for
other aquatic organisms present. The larvae of Anopheles
mosquitoes feed on the water surface and the active ingredient
produce mortality after ingestion. Spreading oil formulations
of essential oil may directly be dropped on the surface of
water sources like lake, pond, etc., and the formulations will
be nontoxic to non-target organisms, fish and other aquatic
species. The application does not require any spray, and good
control of mosquito larvae may be obtained just by dropping
it on the water surface. The formulations designed in the
laboratory have the characteristics of maintaining the
networking film throughout the water surface, and under
natural conditions, the film remains in networking condition
even after the winds and water waves.
Advantages
Botanical based thus safe for non-target organism
Easy to pour and measure
May give enhanced biological activity
Non flammable
Low cost of formulation
Fig 5: Spreading Oil Formulation
5.2. Floating Tablets
The floating tablets are slow release tablets which after
application in water bodies floats on the surface of water due
to low specific gravity and specific inert ingredients (Fig. 6).
The floating tablets offer a simple and practical approach to
achieve increased surface-residence time for the dosage form
and sustained active ingredients’ release. It can reduce the
frequency of dosing required for mosquito larval control and
decrease variation in larvicidal concentration. Floating tablet
formulations of botanical may directly be applied on surface
of water sources like lake, pond, etc.; the formulations will be
non-toxic to non-target organisms, fishes and other aquatic
species. The application does not require any spray, and good
control of mosquito larvae may be obtained just by dropping
it on the water surface. The release of active ingredient from
the formulations may be designed based upon the type and
infestation of the target species.
Advantages
Dust free
Easy packaging
Easy to handle and apply
Long shelf life
Adjustable release rates
Fig 6: Floating Tablets
5.3 Nanoemulsion
Botanical-based Nanoemulsion may be a good alternative of
synthetic pesticides for mosquito control spray application
(Fig. 7). Due to finer droplet size, total surface area is
increased many folds so total coverage of target site also
increases as results dose rate can be reduced to some extent.
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Advantages
Low dose rate
No skin and eye irritation
Less or no solvent
Minimal toxicity
No flammability
A number of essential and botanical oil-based Nanoemulsions
have been prepared with insecticidal activity for mosquito.
These Nano emulsions may be a good alternative to any
kinetically stable emulsion or suspension used for spray
application.
Fig. 7: Nanoemulsion
5.4 Nanogel
Nanogels are typical formulations mainly of the size range of
100 nm, by varying solvent quality and branching the volume
fraction, one can alter variably to maintain a three
dimensional structure. Recently in our laboratory, we have
developed a nanogel formulation for long lasting
impregnation of this insecticide in the dresses which can
protect personals from mosquito bite whenever they are
deployed/posted to work in forest areas. This type of nanogel
formulation may have good future in seed dressing/coating
because of its lower particle size, large surface area and
greater adhesive properties.
6. Conclusion
The real benefits of botanical insecticides can be best realized
in developing countries, where people may not be able to
afford synthetic insecticides, and the traditional use of plants
and plant derivatives for protection of mosquitoes is long
established. Even where synthetic insecticides are affordable
to people (e.g.- through government subsidies), limited
literacy and a lack of protective equipment result in thousands
of accidental poisonings annually. Recently, attention has
been paid to traditional plants used in India for protection
against mosquitoes.
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... Another observation is that PCL45:Plu:Co monoliths floated on the water surface, and the smallest droplet size of copaiba oleoresin in water was measured for samples processed at 850 kg.m -3 . It is well known that mosquito females lay eggs on the water surface [49], and the predominant feeding mode of A. aegypti larvae is collecting, filtering, and shredding fine particulate materials on the liquid surface [16]. Thus, the buoyancy, higher porosity, higher hydrophobicity, and the smallest droplet size of copaiba oleoresin from PCL45:Plu:Co monoliths may have contributed to the observed larval mortality. ...
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Copaiba oleoresin (Co), a promising bioactive agent to control Aedes aegypti proliferation, was incorporated by supercritical carbon dioxide (scCO2) foaming/mixing method (SFM) in two types of poly(ε-caprolactone) (PCL), PCL45 and PCL50, using Pluronic F-68 (Plu) as a surfactant and porogenic agent. The SFM was performed at 35 ºC, scCO2 densities of 750 and 850 kg.m⁻³, soaking time of 2.5 h, and depressurization rate of 5 bar.min⁻¹. The physicochemical characterization of monoliths, the in vitro release, and larvicidal activity against A. aegypti larvae were evaluated. All monoliths with copaiba oleoresin presented larvicidal effects. The best results were observed for PCL45:Plu:Co (56:3:41) monoliths at 750 and 850 kg.m⁻³. This result can be attributed to the higher hydrophobicity of PCL45 than PCL50. These findings indicate that copaiba oleoresin-loaded PCL:Plu:Co monoliths are innovative and sustainable materials capable of controlling the proliferation of A. aegypti larvae and insects to avoid mosquito-borne diseases.
... Moreover, efforts to curb the disease are confounded by the need to control the biting behavior and widespread distribution of Anopheles vectors that facilitate transmission of the parasite. In recent times other mosquito species have also been shown to be permissive to infection [27,28]. Due to these complex and compounding factors, how to combat malaria is regarded to be one of the greatest and most enduring problems faced by humanity [20,26]. ...
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