Aedes Aegypti mosquito: the vector behind dengue, yellow fever, and other diseases

18 Jun 2024

Written by Maya Cherian, Public Health Medical Officer
Reviewed by Dr Nick Walsh MD PhD(epi) BScMed(hons) MPH FAFPHM FAChAM

The Aedes Agypti (A. aegypti) mosquito can be found in tropical and subtropical areas worldwide. The A. Aegypti mosquito is a small, dark mosquito that can be identified by the white bands on its legs and a silver-white pattern of scales on its body. The mosquito has been compared to the Greek musical instrument, the lyre (Figure 1).¹

Figure 1: Lyre

The mosquito has been compared to the
Greek musical instrument, the lyre.

The A. Agypti mosquito comes from the family Culicidea, genus Aedes and Subgenus Stegomyia. It takes approximately 7-10 days for an egg to develop into an adult mosquito (Figure 2).²

Figure 2: A. Aegypti life cycle

Figure 3: Eggs

Female mosquitoes need a small amount of water to lay eggs, laying just above the water line. Eggs are able to survive drying out for months, as well as northern hemisphere winters (Figure 3).²

When water covers the eggs, the eggs hatch into larvae, which live in the water (Figure 4).²

Figure 4: Larvae

Figure 5: Papu

Larvae then develop into pupae (Figure 5),² which adult mosquitoes emerge from with a total life span of approximately three weeks.

The A. Agypti don’t travel long distances, moving only a few blocks and have a total life span of approximately three weeks.

The A. Aegypti mosquito has historically been found in tropical and subtropical areas in forested areas. Over time geographic spread has increased to include Europe, the Southern Cone of South American and the United States.³ With urbanisation, the mosquito can survive in a wide range of artificial containers, adapting to both indoor and outdoor aquatic container habitats.

Disease transmission

The A. Aegypti mosquito is the vector for dengue, yellow fever, chikungunya and Zika virus (Table 1).⁴ It has been identified as a potential vector for Venezuelan equine encephalitis virus and studies have shown it is capable of transmitting West Nile virus.⁴

Summary of diseases transmitted by Aedes Aegypti mosquito

Climate change and the Aedes Aegypti mosquito

There have been ongoing concerns for many years on the effects of climate change on mosquito populations. Without reductions in greenhouses gases, temperatures will continue to rise, favouring the development of new mosquito development.¹² The prevalence of vector-borne diseases has increased with malaria, dengue, lyme disease and West Nile virus infection expected to further rise if appropriate control strategies are not implemented.¹³ Surveillance and control form the basis of community and household or individual adaptation strategies to respond to vector-borne diseases with adaptation measures required to decrease the impact of such diseases.¹³

Novel methods for decreasing transmission

The World Mosquito Program (WMP) is a not-for-profit group¹⁴ led by Monash University. The WMP is leading research into preventing the transmission of vector-borne diseases using Wolbachia. Wolbachia is an intracellular bacterium safe for humans and the environment that naturally occurs in 50% of arthopod (including insects) species. Its presence upregulates host immune mechanisms, resulting in an ‘antiviral’ effect. A. Aegypti does not normally carry Wolbachia; however, other mosquitoes do. Wolbachia blocks the growth of viruses such as dengue, yellow fever, chikungunya, and Zika in A. Aegypti mosquitoes. Wolbachia mosquitoes have been released at a number of sites in northern Australia over the past decade and more recently overseas, resulting in the replacement of the mosquito population and a decreased dengue incidence by 77% and dengue hospitalisation by 86%. Food chains or population size are not decreased by Wolbachia.

References

Dr Maya Cherian
Public Health Physician

Maya is a Public Health Physician, joining NCCTRC as a registrar in 2023. Maya has experience in Aboriginal health, public policy, communicable diseases, statistics and health economics. Maya is excited to contribute to the fabric of the organisation and assist in enhancing the public health components of NCCTRC, through education, research and policy.