Anopheles gambiae: Recent Findings and Control Measures

This brochure provides recent findings on Anopheles gambiae, the most efficient vector of malaria in the Afrotropical region. It covers topics such as host-pathogen interaction, insecticide resistance, and natural essential oils. Additionally, it discusses ethnobotanical knowledge and how it can be used to prevent mosquito bites. The brochure is intended for those suffering from African malaria or researchers interested in recent research in this field.

Running head: BROCHURE DOCUMENTS ON Anopheles gambiae
BROCHURE DOCUMENTS ON Anopheles gambiae
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BROCHURE INFORMATION ON Anopheles gambiae
Topic
The brochure focuses on the causative agent of the African malaria (Anopheles gambiae).
It is considered as the most efficient vector of malaria in the Afrotropical region (CDC 2010). It
mainly composed of eight isolated reproductive species that cannot be distinguished
morphologically. This brochure will focus on some of the recent findings regarding Anopheles
gambiae aiming to reduce its ill effect.
Audience
The audience of this brochure is group of people who have been suffering from African
malaria or for the researchers who are keen to do research or gain knowledge about the recent
researches in this field.
The purpose of this brochure is to give an understanding on the current findings on
Anopheles gambiae, its host pathogen interaction in the midgut that is responsible for the
infection. The brochure would further provide the knowledge how the mosquitoes are gaining
resistance over the insecticides and the recent recommendations. It also provides an in depth
knowledge about the components of some natural essential oils containing repellant property and
also provides with the information regarding the tribal traditions of using herbs and plants to
prevent the vectors.

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Annotated Bibliography
Boissière, Anne, et al. "Midgut microbiota of the malaria mosquito vector Anopheles
gambiae and interactions with Plasmodium falciparum infection." PLoS pathogens 8.5
(2012): e1002742.
The vulnerability of the Anopheles mosquito to the plasmodium infections depends
mainly on the complex interaction between the vectors and the malarial parasite. a number of
studies have referred to the fact the mosquito poses an immunity to control the malarial
infection, but very little is known about the role of the environmental factors in the process of
transmission.
It has been found that it is the gut microbiota that is actually responsible for the mosquito
infection. A. gambiae mosquitoes were isolated from Cameroon and were experimentally
challenged with P. falciparum isolate and the bacterial content of the gut is subjected to
pyrosequencing analysis. On testing a broader richness was found in the gut microbiota. It was
found that during the development of the Plasmodium parasites in the mosquito vector, they
undergo complex phases. Parasite losses occur in the midgut of the mosquito where the immune
system actually comes in to play. In the genetic and the environmental factors that actually helps
in the infection.
The midgut microbiota of the adult mosquito contained five dominant phyla notably
Proteobacteria, Actinobacteria, Bacteroidetes, Fusobacteria, Firmicutes. It is after the blood
meal, when the parasites actually takes the advantage of the competitive interaction that takes
place between the bacteria for the nutrients and the host protection is overlooked by the bacteria
due to the competition. Although the gut microbiota helps in the homeostasis and protecting the

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mosquito from external infection yet viruses and pathogens have found out ways to destroy the
barrier. However the gut system of the mosquito remains poorly understood and are still under
research. Unraveling of the strategies applied by the parasites to cooperate with the gut
microbiota will provide a better understanding of the interaction between the host and the
pathogen.
Ranson, Hilary, and Natalie Lissenden. "Insecticide resistance in African Anopheles
mosquitoes: a worsening situation that needs urgent action to maintain malaria control."
Trends in parasitology 32.3 (2016): 187-196.
The resistance of the Anopheles Gambiae to the pyrethoid insecticides has become a
matter of concern over the afro-tropical region. The prevalence of the strength of the resistance
has increased dramatically over the past few years. This paper provides information of the recent
resistance status of the mosquitoes to the major insecticide classes. Data on the resistance of
Anopheles gambiae was thought to be restricted to the southern part of Africa but has been later
on detected in Uganda, Benin, Kenya and Cameroon. Most of the Anopheles gambiae shows
susceptibility to the carbamates and the organophosphates. The reports of the resistance to the
two classes of insecticides have also got from the areas where the pyrethoids have been replaced
by the carbamates. The insecticide resistance of the malarial vectors has posed a serious threat to
the malarial control programs and keeping a track of the spread of the resistance is a challenge
for the malaria control program.
The insecticide resistance of the malarial vectors has posed a serious threat to the malarial
control programs and keeping a track of the spread of the resistance is a challenge for the malaria
control program. The mathematical models of the malaria transmission can be used for

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translating the entomological outcome of the experimental hut trials for estimating the number of
the malaria cases due to resistance. The resistance to the insecticides has posed a question to the
future trends of the causative agent over the insecticides and the rising cost of the control
measures. Despite the rapid emergence of the resistance, the mosquito sleeping nets can still
provide protection against malaria even in those areas with pyrethroid resistance.
WHO had published a Global plan for the Insecticide resistance management in the
malaria vectors (GPIRM). Reports have emphasized on the effectiveness of the Indoor residual
spraying system and the insecticidal mosquito nets.
Reflecting about the future prospects, there should be new insecticides for counteracting
with the rapid emergence of the resistance against insecticides. Two companies have developed
new LLINs containing the pyrethoid synergist piperonyl butoxide for preventing mosquito which
will be able to give more protection against the pyrethoid resistance mosquitoes.
Protopopoff, Natacha, et al. "High level of resistance in the mosquito Anopheles gambiae to
pyrethroid insecticides and reduced susceptibility to bendiocarb in north-western
Tanzania." Malaria Journal 12.1 (2013): 149.
In relation to the previous paper this paper provides the information for the high level of
resistance in the mosquitoes Anopheles gambiae to the pyrethoid insecticides and the lessened
vulnerability to bendiocarb in the north-western Tanzania. This report gives information about
investigation of the kdr resistance allele involved in the pyrethoid resistance. Household
collections of the African malaria Anopheles mosquito were exposed to pyrethoids, bendiocarb
and DDT using the test resistance kit .It was found that Anopheles gambiae has developed a

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phenotypic resistance to DDT and pyrethroids and DDT. Two major mechanisms have been
considered to be responsible for the pyrethroid resistance. One is the target sensitivity which is
also the knock down resistance kdr. The second cause is the metabolic resistance due to the
elevated levels of the detoxifying enzymes. kdr is mainly caused by the mutations in the sodium
channels. A change has been observed in leucine to phenylalanine. Recent reports have indicated
towards a new mutation in the sodium channel conferring additional resistance to Permethrin and
DDT.
In order to reduce the burden of malaria in Tanzania, the national malaria Control
program in Tanzania had been increasing the coverage of the bed nets and the IRS. Previous
surveys conducted had shown no resistance to DDT or pyrethroids. A study that was carried out
previously also did not show much resistance to deltamethrin and DDT, but the current study in
Tanzania had shown resistance against the following insecticides. After the WHO insecticide
resistance test, Anopheles gambiae showed reduced vulnerability to the carbamate bendiocarb in
the WHO resistance test and is found to be in widespread through the various region of Muleba.
Kweka, Eliningaya J., Annadurai Senthilkumar, and Venugopalan Venkatesalu. "Toxicity
of essential oil from Indian borage on the larvae of the African malaria vector mosquito,
Anopheles gambiae." Parasites & vectors 5.1 (2012): 277.
Study of essential oils for the control of the disease causing vectors has long been a topic
of research. This paper discus about the toxic effect of the essential oils extracted from the Indian
borage (Plectranthus amboinicus) on the larva of the African Malaria mosquito larvae. The use

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of synthetic insecticides that was predominant over time to kill the mosquitoes has shown
reduced efficiency with time. This occurs due to the resistance developed by the female
anopheles mosquito against the synthetic insecticides used in the bed nets or the Indoor residual
spray. The resistance factor has lead to a public health problem all over the region of Africa.
Targeting the larva of the mosquito by the larvicides can be beneficial at one point as it cannot
move from the breeding sites. In the recent years new mosquito control agents have been found
to be extracted from the natural sources like the essential oils. A large number of plants or
essential oils have been reported to have mosquito repellant or larvicidal activity.
Indian borage Plectranthus amboinicus belongs to the family Lamiaceae and it grows naturally
in tropical Africa and Asia. A colony of Anopheles gambiae was reared in the laboratory and
eggs were collected on the filter paper and kept in the incubator 48 hours before the time of
hatching. The larvae were developed to the third larval stage. The third instar larva was used to
test the activity of the larva.
The chemical content of the sample taken from P.amboinicus was analyzed and 26 essential
compounds were found to be responsible for the larvicidal activity. The laboratory results
showed 100% larval mortality when exposed to 100 ppm of the essential oils for 48 hours. The
presence of Carvacrol in the essential oils has found to be the primary component responsible or
the larval mortality. The rate of the mortality was dosage and time dependant.

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Pavela, Roman, and Giovanni Benelli. "Ethnobotanical knowledge on botanical repellents
employed in the African region against mosquito vectors–a review." Experimental
parasitology 167 (2016): 103-108.
Mosquitoes act as a huge thread to mankind as they are the vectors of harmful pathogens and
parasites. Some of the tribal inhabitants of the African regions have been using the repellant
plants for avoiding the mosquitoes. The ethnobotanical knowledge was usually passed orally
from one generation to the next. However it is essential to preserve the knowledge in a
documented form. The ethno-botanical research projects, has been carried out in South Africa,
Ethiopia, Nigeria, Tanzania, Kenya. It has been found that the native inhabitations use almost 64
plant species of plants as mosquito repellant. According to the reports the native people generally
use three methods of using the repellant plants, one by producing the smoke by burning the
plants, by hanging the branches inside the house and by using the essential oils extracted from
the crushed part of the plants over the exposed part of the body. It has been found that that using
bed nets synergized with botanical repellants applied on the body parts can help to avoid the
bites of the mosquito vectors. Burning of herbs such as Artemisia spp. and Acorus calamus
species are used in rural Africa. Smoke produced by burning the dried leaves of Azandirachta
indica has also been used for repelling the mosquito since the ancient times. Direct burning of
plants like O.basilicum showed a very high percentage of repellency against Anopheles gambiae.
C.citriodora had shown highest repellency. This review covers studies based only on a small
part of Africa and hence it is important to conduct further researches for preserving the unique
traditions and the knowledge of the tribes.

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References
Boissière, Anne, et al. "Midgut microbiota of the malaria mosquito vector Anopheles gambiae
and interactions with Plasmodium falciparum infection." PLoS pathogens 8.5 (2012): e1002742.
Kweka, Eliningaya J., Annadurai Senthilkumar, and Venugopalan Venkatesalu. "Toxicity of
essential oil from Indian borage on the larvae of the African malaria vector mosquito, Anopheles
gambiae." Parasites & vectors 5.1 (2012): 277.
Pavela, Roman, and Giovanni Benelli. "Ethnobotanical knowledge on botanical repellents
employed in the African region against mosquito vectors–a review." Experimental parasitology
167 (2016): 103-108.
Protopopoff, Natacha, et al. "High level of resistance in the mosquito Anopheles gambiae to
pyrethroid insecticides and reduced susceptibility to bendiocarb in north-western Tanzania."
Malaria Journal 12.1 (2013): 149
Ranson, Hilary, and Natalie Lissenden. "Insecticide resistance in African Anopheles mosquitoes:
a worsening situation that needs urgent action to maintain malaria control." Trends in
parasitology 32.3 (2016): 187-196.