**1. Introduction**

Mosquitoes are small, midge-like flies that constitute the family Culicidae. Females of most species are ectoparasites feeding on vertebrates' blood through piercing the hosts' skin to suck the blood. To-date, approximately 3500 species of the Culicidae have been described. The family Culicidae is a large and abundant group which occurs throughout temperate and

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

tropical regions of the world and well beyond the Arctic Circle [1]. There are two subfamilies of Culicidae, that is, the Anophelinae (3 genera) and the Culicinae (110 genera). The subfamily Culicidae, *Aedes* is the largest tribe of mosquitoes with 1256 species classified into 10 genera: Aedes sensu (931), Armigeres (58), Eretmapodites (48), Haemagogus (28), Heizmannia (38), Opifex (2), Psorophora (49), Udaya (3), Verrallina (95), and Zeugnomyia (4) [2].

The geographic distribution of *Ae. aegypti* based on the order of higher levels of occurrence for each continent reveals that in the Americas, the Brazil ranks the highest (**Table 1**). In Africa, occurrence of the vectors have been recorded in Senegal, Cameroon, Kenya, Tanzania, Ivory Coast, Nigeria, Madagascar, Gabon, and Sierra Leone (**Table 1**). In Asia/Oceania, occurrence

Ecology of *Aedes* Mosquitoes, the Major Vectors of Arboviruses in Human Population

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*Ae. aegypti* is an arthropod closely associated with humans and their habitats. They are mostly anthropophilic [13] with high preference to the urban environment [14]. They get blood meals from human, and human creates conducive environment for their population growth through up haphazardly disposal of water-holding containers/obsoletes around our homes. The mosquito lays her eggs on the sides of containers with water, and eggs hatch into larvae after a rain or flooding. A larva changes into a pupa in about a week and into a mosquito in 2 days. The *Aedes* main habitat is aquatic, and they can thrive better from tree cavities to toilets. People also furnish shelter as *Ae. aegypti* preferentially rests in darker cool areas, such as

*Ae. aegypti* has adaptations to the environment that makes them highly resilient, or with the ability to rapidly bounce back to initial numbers after disturbances resulting from natural phenomena (e.g., droughts) or human interventions (e.g., control measures). One such adaptation is the ability of the eggs to withstand desiccation (drying) and to survive without water for several months on the inner walls of containers. For example, if we were to eliminate all larvae, pupae, and adult *Ae. aegypti* at once from a site, its population could recover 2 weeks later as a result of egg hatching following rainfall or the addition of water to containers har-

It is likely that *Ae. aegypti* is continually responding or adapting to environmental change. For example, it was recently found that *Ae. aegypti* is able to undergo immature development in broken or open septic tanks resulting in the production of hundreds or thousands of *Ae. aegypti* adults per day. In general, it is expected that control interventions will change the spatial and

*Aedes albopictus* (*Stegomyia albopicta*), from the mosquito (Culicidae) family, also known as (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia; however, in the past few decades, this species has spread to many countries through the transport of goods and international travel [15]. The eggs of *Ae. albopictus* are desiccation resistant, which enhance survival in inhospitable environments [16]. *Ae. albopictus* is among the aggressive outdoor species of mosquito, and they are day biter that has a very broad host range and attacks humans, livestock, amphibians, reptiles, and birds [17]. Their biting rate level can be as high as 30 to 48 bites per hour [18]. *Ae. albopictus* survives at a large range of

temporal dispersal of *Ae. aegypti* and perhaps the pattern of habitat utilization.

of *Ae. aegypti* has been reported and documented (**Table 1**) [3, 12].

**1.2. Ecology of** *Aedes* **mosquitoes**

closets leading to their ability to bite indoors.

*1.2.1. Aedes aegypti*

boring eggs.

*1.2.2. Aedes albopictus*

temperatures [19].

The public health concern of *Aedes* mosquitoes particularly *Ae. aegypti* and *Ae. albopictus* in the transmission of arboviruses such as dengue virus, chikungunya virus, ZIKV virus, and yellow fever virus is kept on increasing globally. Over half of the world's population is at risk of dengue and chikungunya infections [3]. The Caribbean, South America, and Europe are no longer spared from chikungunya infection, a disease which was previously limited to Africa and Asia [3]. According to the World Health Organization, about 2.5 billion people globally live in dengue endemic regions [4]. Dengue is the most worldwide important mosquito-transmitted viral infection [4]. Over 100 countries in Africa, North and South America, Southeast Asia, Europe, and the Pacific are reported to have had severe dengue outbreaks [5]. The annual occurrence of dengue fever infections ranges from 50 to 100 million with which around 500,000 facing severe morbidity causing to over 20,000 mortalities, pediatrics beings the most cases [5]. The chikungunya virus infections (CHIKV) have been documented in over 60 countries in Asia, Africa, Europe, and the Americas [6]. The estimated number of chikungunya cases in Americas in 2016 was 693,000, and Zika virus (ZIKV) disease was 500,000 [6, 7]. Yellow fever cases in Africa were 130,000 with an estimated 31,000 annual disability adjusted life years and 500 deaths [8, 9].

About 80% of the world's population is at risk for at least of exposure to one vector-borne disease; these diseases account for about 17% of the estimated global burden of communicable diseases and cause over 700,000 deaths annually, affecting disproportionately poorer populations [6, 9]. They hamper economic development through direct medical costs and indirect costs such as the loss of productivity and tourism. The social, demographic, and environmental factors strongly influence transmission patterns of vector-borne pathogens. Vector control is an important component for decision science in the prevention and control of vector-borne disease approaches. Consequently, the global distribution and ecology of these vectors and the geographical determinants of their ranges are essential in order to be effective. Therefore, it is important to work out where these mosquito species are found around the globe to identify the areas at risk. It is also important to predict where these species could become established if they were introduced, in order to identify areas that could become at risk in the future.
