Everyone knows that the sound of a mosquito near your bed as you’re trying to fall asleep can feel like a slow torture. For many people around the world, that mosquito also comes with the risk of contracting malaria, a potentially life-threatening disease. The World Health Organization (WHO) estimates that as of 2015 about 3.2 billion people live in areas that are malaria affected, and as temperatures rise with climate change that number could increase. The highest risk of contracting malaria remains in Africa.
Previous efforts to curb malaria (including insecticide-treated mosquito nets and indoor residual sprays) have had positive results – studies estimate that nearly 700 million cases have been avoided since 2000 when efforts to curb the disease intensified. The WHO estimates that malaria deaths have fallen by 60% since 2000. An estimated 663 million possible cases have been prevented.
Yet, more than 400 000 people died of malaria in 2015, and 90% of these were in Africa, and most of them were under the age of five. Whilst these may feel like bleak statistics, the efforts to curb malaria continue to be increasingly innovative. In addition, these alternatives combat the gaps in success provided by measures such as nets and sprays – and reduces the use of pesticides, which are harmful to more than just the mosquito.
Two new methods in particular work with an odour to repel mosquitos or to trap them, reducing the population of people in risk areas who are exposed to malarial mosquitos. Mosquitos primarily use their sense of smell to find suitable host species. Although using odour isn’t new – who hasn’t lit a citronella candle when sitting outside in summer – the particular odours are.
The first uses of human odour-baited traps to attract mosquitos have shown an incredible 70% decline in the mosquito population and a 30% decline in new infections on the Kenyan Island of Rusinga. The trial used a combination of nets, anti-malarial medicine, a social strategy, and the traps to achieve these astounding results. The traps themselves require electricity, and so an additional positive spin-off was the installation of solar power to run them and to provide energy to the residents of the Island.
The second odour-related innovation uses, believe it or not, chickens! New research indicates that chickens may release an odour that repels mosquitos. Although this study is only in preliminary stages, evidence showed that traps that were laced with compounds from chicken feathers repelled more mosquitos than traps laced with other animal odours. Although the thought of sleeping with a chicken near your bed might not appeal to you, the science suggests that if mosquitos actively avoid chickens, there may also be additional odours that can be used to repel mosquitos away from risk areas.
The WHO hopes to eradicate malaria by 2030. Preventing the spread of the disease not only saves funds for health departments. It keeps children healthy and allows adults to continue to work, overall contributing to increased community wellbeing.