Please note! This essay has been submitted by a student.
During the monsoon periods of June to October, it was detected that there is a rise of mosquito breeding areas and transmission of mosquito-borne diseases. During warmer and wetter months, mosquito breeding and maturation cycles are much shorter. This leads to rapid growth of the mosquito population and a much shorter incubation period for mosquito-borne diseases such as the most common and deadly one, dengue. According to National Environment Agency (NEA), it was detected that there were a 22 per cent increase in Aedes Aegypti, a mosquito known to transmit Dengue, in the first three months of this year, 2018, as compared to the previous three 3 months. NEA manages to detect and monitor mosquitos using “gravitraps” – black cylindrical devices that are placed around residential areas. It was also noted that mosquitoes are able to lay eggs and breed in almost any source of stagnant water and do not require much of it. Places include the artificial or natural water containers, like the water collection tray of potted plants, puddles, drains or water collected on top of dustbins or garbage. During monsoon periods, water collection due to rain are more likely, leading to increased breeding zones for mosquitoes. Mosquito eggs usually hatch into larvae in half a day and takes only 6 days to emerge into an adult mosquito, where it is able to bite and consume blood from hosts. It then lives on for about two weeks, laying about a hundred eggs in its entire lifespan. To makes things worse, mosquitos can lay their eggs in a dry and safe place, where it can lie inactive for about nine months. After conditions are right; enough water and food, it would then emerge from their eggs to continue the cycle. If these mosquito breeding grounds are left unattended, this would result in the increase of the mosquito population. This can lead to an outbreak of mosquito-borne diseases.
Different mosquito species can spread different diseases. This is a problem as these diseases can be fatal. For example, the Aedes Aegypti, is known for spreading Dengue, Chikungunya and a most recent virus, Zika. Dengue, being ranked as the most serious mosquito-borne viral disease in the world by the World Health Organisation (WHO) has seen a 30% increase in infection in humans all around the world over the past 50 years. Every year, around 390 million people contract Dengue of which 25000 are fatal with more than 40% of the world’s population at risk. Most of these deaths consists of children under the age of 15. Being a virus, it has different serotypes. Dengue has 4 main ones, of which, each have different severity. These serotypes can also result in an increased difficulty of creating a vaccine which can prevent Dengue entirely.
Zika, while discovered in 1952, had its first outbreak in 2015. It was observed that Zika had a correlation with microcephaly and the Guillain-Barre Syndrome in babies if their mothers where infected while pregnant. Over 500 thousand cases were reported since this outbreak, with over 3 thousand cases of congenital brain abnormalities found in just-born babies. Being a more recent outbreak, no vaccine or treatment for zika is available.
While no vaccinations are currently available for these viruses, some methods are already in operation to wipe out these mosquitos or prevent further transmission of these diseases.
Wolbachia is a natural bacterium found in most insect species but is not prevalent in the Aedes aegypti mosquito. Scientists have managed to introduce this bacterium, which is harmful to humans, into mosquitos and have made a breakthrough; mosquitos infected with Wolbachia do not transmit viruses like Dengue. Male mosquitos, infected with Wolbachia have been released and it was found that when they mate with wild female mosquitoes without Wolbachia, eggs laid do not hatch. However, this method is a long-term solution and it may have unprecedented effects on the environment. A sudden loss in a population of a species can result in the lack of pollination of flowers in plants; male mosquitos do not suck blood but help in the pollination of plants when they consume its nectar. Also, mosquitos, are a main source of food to some organisms like spiders or frogs. Wolbachia, while is negligible in terms of effects to humans, may develop unknown symptoms which is not known yet and would need further examination in the long-run. Furthermore, the costs of engineering and infecting these mosquitos with the Wolbachia bacteria can be costly and need good conditions when releasing them into the wild.
As such, a fast and cheap method is required to eliminate the rising population of mosquitos, especially in cites. A method that is convenient and takes no time at all to carry out is preferred as most of mosquito breeding areas are water containers which are left unattended.