Aedes

Aedes is a genus of mosquitoes that is originally found in the tropical and subtropical zone. Except for Antarctica, the Aedes mosquitoes are found on every continent. Few species of these mosquitoes are spread by human activities, for example, Aedes albopictus is a particularly invasive species that was found to be recently spread all over the New World, which includes the United States, China, etc. 

Aedes was first described and named by the German entomologist Johann Wilhelm Meigen in the year 1818 and the generic name came from the Ancient Greek word aēdēs which translates to unpleasant or odious. Aedes cinereus is the type of species for Aedes. Dengue fever, yellow fever, the Zika virus, and chikungunya are all illnesses transmitted by some species of this genus. The Aedes polynesiensis species is responsible for the transmission of human lymphatic filariasis in Polynesia. Aedes is known to be detected and monitored by ovitraps.

The yellow fever mosquito, Aedes aegypti, is a disease-carrying mosquito that may spread dengue fever, chikungunya, Zika fever, Mayaro, and yellow fever viruses, among other diseases. White patterns on the mosquito's legs and a lyre-shaped pattern on the upper side of its thorax help to identify it. This mosquito is native to Africa, although it may currently be found in tropical, subtropical, and temperate climates all over the world.

The Broad Institute and the Institute for Genomic Research sequenced the genome of the yellow fever mosquito (Aedes aegypti). The initial assembly was provided in August 2005, followed by a preliminary genome sequence and early analysis in June 2007. VectorBase has the annotated genome accessible. In 2018, an upgraded and updated version of the Aedes aegypti genome was revealed.

In this article, we are going to discuss all the aedes mosquitoes such as the disease caused by aedes mosquitoes, distribution and population control methods applied all across the world, the life cycle of the aedes mosquito, and also a few of the most frequently asked questions will also be answered. 

Aedes Mosquito

• Aedes is a genus of more than 950 species of mosquitoes of order Diptera in which few members of this genus are considered to be very serious biting nuisances and are considered to spread vectors of diseases of which sometimes also transmits potentially deadly pathogens which are disease-causing organisms to humans and other animals.

• Aedes mosquitoes are found in temperate and tropical environments all over the world. Some species, on the other hand, have spread outside their natural ranges as a result of the human introduction into new places or altering environmental effects. The introduction of Aedes aegypti from Africa and Aedes albopictus from Asia to the Americas has aided the development of several devastating infectious illnesses, including chikungunya fever, dengue fever, and Zika fever.

Physical Features of Aedes 

• The black and white markings on the bodies and legs of Aedes mosquitoes distinguish them from other mosquitoes. They are active and bite only during the day, unlike most other mosquitoes. The best times to bite are early in the morning and before dusk in the evening.

• Adult Aedes mosquitos are distinguished from other mosquito species by their narrow, black bodies, distinctive patterns of light and dark scales on the abdomen and thorax, and alternating light and dark bands on the legs. Females are further identified by their maxillary palps which are the sensory organs connected with the mouthparts, they are shorter than the proboscis, and by the curvature of their abdomen, which normally comes to a point at its tip. When landed, Aedes mosquitos hold their bodies low and parallel to the ground, with the proboscis angled downward.

• The members of the Aedes are known to be the vectors for transmitting numerous viral infections. Dengue fever, yellow fever, West Nile fever, chikungunya, eastern equine encephalitis, and Zika virus are all transmitted by Aedes aegypti and Aedes albopictus, as well as many more, less well-known illnesses. These viruses are usually accompanied by a fever and, in some cases, encephalitis, which can result in death. Insecticides such as DDT, mosquito traps, insect repellents, and mosquito nets are all available to defend against mosquito bites.

• An image of the adult Yellow fever mosquito is given below 

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Aedes Mosquito Life Cycle

• The life cycle of the Aedes mosquito usually consists of four stages which are the egg, larva, pupa, and adult stage. The adults emerge anywhere from seven days to several weeks after the egg is hatched. 

• Eggs: 

1. Females generate 100 to 200 eggs each batch after having a complete blood meal; however, the quantity of eggs produced depends on the quantity of the blood meal. During her lifetime, a female can produce up to five batches of eggs. Fewer eggs are produced when the blood meal is smaller.

2. Eggs are placed single rather than in a mass on moist surfaces in regions prone to flood briefly, such as tree holes and man-made containers. Not all of the eggs are deposited at the same time, but rather over a period of hours or days. Female mosquitos deposit their eggs above the waterline on the interior walls of containers with water. Eggs are usually laid at various heights above the water level, and a female will not lay the entire clutch at one location, but rather spread them out among two or more.

3. Aedes aegypti eggs are around one millimeter long, smooth, and oval-shaped. When eggs are originally deposited, they seem white, but they quickly acquire a lustrous black color. Eggs can develop in as little as two days in warm regions like the tropics, but it can take up to a week in cooler temperate areas. Aedes aegypti eggs may survive months of desiccation and hatch once submerged in water, making Aedes aegypti management challenges. Eggs cling to the insides of containers like glue. They can withstand being exposed to the elements for up to 8 months. In the southern United States, mosquito eggs may even survive a winter.

4. Mosquitoes simply require a little water to deposit their eggs. Bowls, cups, fountains, tires, barrels, vases, and any other water-holding container make excellent "nurseries."

5. An image of the yellow fever mosquitoes eggs are given below 

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• Aedes Larvae

1. Larvae eat algae and other minute creatures that live in the water as organic particulate matter. Aedes aegypti larvae spend most of their time at the top of the water, however, they will swim to the bottom of the container if disturbed or when eating.

2. Larvae are known to live in water. They hatch from the mosquito eggs. The larval stage usually happens when the water which gets stored by the rain or a sprinkler gets covered with the eggs. 

3. Mosquito larvae are sometimes referred to as "wrigglers" or "wigglers" because when disturbed, they appear to wiggle erratically in the water. Aedes aegypti larvae breathe oxygen through a posteriorly positioned syphon that is kept above the water's surface while the remainder of the body hangs vertically. The small syphon of most Aedes larvae distinguishes them from other genera to the unassisted eye.

4. Larvae can be discovered in puddles, tires, and any other water-holding object around the house. Temperature affects larval development. The larvae go through four instars, each of which lasts for a few hours in the first three and up to three days in the fourth. Larvae in the fourth instar are around eight millimeters long. Males grow at a quicker rate than females, therefore they pupate early. Aedes aegypti may stay in the larval stage for months if the temperature is cold and the water supply is adequate.

5. An image of the fourth instar larva of the yellow fever mosquitos is given.

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• Pupae

1. Mosquito pupae vary from the pupae of many other holometabolous insects in that they are mobile and react to stimuli. Pupae, often known as "tumblers," do not eat and mature in around two days. Adults emerge by inhaling air, which causes the abdomen to expand, breaking apart the pupal case and allowing them to emerge head first.

2. Pupae live in water and as times fly by an adult mosquito usually emerges from pupae and then flies by.

3. An image of the Pupae of the yellow fever mosquito is given below

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• Adult 

1. Female mosquitos attack both humans and animals as adults. Mosquitoes require blood in order to lay eggs.

2. Female mosquitoes hunt for water sources to deposit eggs after eating.

3. Aedes aegypti and Aedes albopictus are not long-distance fliers. These mosquitoes will only travel a few blocks throughout their lifespan.

4. Mosquitoes of the species Aedes aegypti love to reside near humans and bite them.

5. Mosquitoes of the genus Aedes aegypti attack humans and animals, thus they can reside in or near homes or in nearby woodlands.

6. Mosquitoes of the Aedes aegypti species dwell both indoors and outdoors, while mosquitoes of the Aedes albopictus species only reside outside.

Aedes Mosquito Disease

• There are multiple species of Aedes that play an important role in the transmission of disease to humans and there are many instances in which several different species can transmit the same pathogen. Although Aedes aegypti is the primary dengue virus vector in Africa and the Americas, Aedes albopictus may also transmit the disease to people in those areas.

• A. polynesiensis is an indigenous dengue vector in French Polynesia. A. scutellaris, a species endemic to the Malay Archipelago, Papua New Guinea, and the Torres Strait region, has also been blamed for dengue epidemics.

• The proliferation of Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus, native to Africa and Asia, is thought to facilitate pathogen absorption and transmission by indigenous Aedes species. Humans who have been infected may also play a role. In French Polynesia, for example, A. polynesiensis is thought to be a Zika virus vector (A. aegypti is the main vector). The virus was first detected on the island country in the year 2013 and it is believed that it had been imported by an infected human or by infected mosquito larvae.

• Researchers stated in 2019 that A. albopictus has been largely exterminated on two islands in Guangzhou, China. The introduction into the wild of female mosquitoes sterilized by radiation in a laboratory and males infected with a strain of the bacterium Wolbachia pipientis, which hampered the males' ability to reproduce and transmit disease, caused the species' population to decline by 94 percent between 2016 and 2019.

Spread of Disease and the Prevention Methods 

• Aedes aegypti is considered to be a vector that is responsible for transmitting several tropical fevers. Only the female bites in order to develop her eggs, which she needs blood for. These mosquitoes are drawn to chemical substances generated by animals, such as ammonia, carbon dioxide, lactic acid, and octanol, in order to find a host. 

• The Agricultural Research Service of the United States Department of Agriculture (USDA) examined the molecular composition of octenol to better understand why this chemical draws mosquitoes to their hosts. The mosquito prefers "right-handed" (dextrorotatory) octenol molecules, according to the researchers. The yellow fever mosquito can also be known as a contributor to the spread of reticular cell sarcoma among Syrian hamsters. 

Prevention Methods 

• The Centers for Disease Control and Prevention's traveler's website on avoiding dengue fever recommends using DEET which stands for N, N-diethyl-meta toluamide, in 20 percent to 30 percent containing insect repellents 

• Aedes aegypti mosquitoes are most commonly known for feeding in the evening time in indoors and shady areas especially when the weather is cloudy. They are known to bite and spread infections all year long at any time of the day. 

• Scrub eggs stuck to damp containers once a week, seal, and trash them. Mosquitos love stagnant water, such as flower vases, exposed barrels, buckets, and abandoned tires, but the most harmful sites are damp shower floors and toilet tanks, which allow mosquitoes to reproduce inside the home. Certain compounds released by bacteria in water containers have been shown to encourage female mosquitos to deposit their eggs, according to research. They are especially driven to lay eggs in water containers that have the right quantity of certain fatty acids linked to bacteria that aid in the decomposition of leaves and other organic waste in the water.

• The compounds in the microbial stew are significantly more stimulating to female mosquitoes than the simple or filtered water in which the bacteria originally thrived.

• When outdoors throughout the day and evening, long-sleeved apparel and long pants are recommended.

• If your bedroom isn't air-conditioned or screened, use mosquito netting over the bed and treat it with permethrin for added protection.

• In a scientific investigation, insect repellents containing DEET or p-menthane-3,8-diol were shown to be efficient in repelling Aedes aegypti mosquitoes, whereas others were shown to be less efficient or ineffective.

• Although an adult Aedes aegypti can live for two to four weeks depending on circumstances, the mosquito's eggs may live for almost a year in a dry state, allowing it to reappear after a cold winter or dry spell.

• A new study looks into the usage of a bacteria called Wolbachia as a biocontrol agent. According to studies, endosymbiotic bacteria invasion of Aedes aegypti makes mosquitoes immune to specific arboviruses such as dengue fever and Zika virus strains currently circulating.

Distribution of the Aedes Mosquito

• The yellow fever mosquito or the Aedes mosquito’s distribution has increased in the past few decades all across the globe and it is considered to be among the most widespread species of the mosquitoes. 

• The yellow fever mosquito has a year-round cosmo-tropical range and spreads to more temperate areas throughout the summer. Aedes aegypti is a mosquito that originated in Africa and today lives in tropical and subtropical areas all over the world.

• The dispersion of Aedes aegypti in the early 1900s spanned the southern United States all the way down to Argentina. The development of a fairly successful Aedes aegypti eradication program throughout its range in North and South America in the mid-1900s as a method to control yellow fever through education, adult mosquito control, and manipulation of container breeding sites saw the development of a fairly successful Aedes aegypti eradication program throughout its range in North and South America in the mid-1900s.