Night Guard: Unfolding the Protective Effects of the Mosquito Net

New technology keeps improving bednets to better protect people from malaria

Ruth Mushinge prepares her mosquito net in her home near Mundabi, Zambia. / John Healey, USAID

Each night, drawn by the breath of humans, Anopheles mosquitoes fly into homes and feed on the blood of sleeping children and adults. For millions of people in tropical and subtropical areas across the globe, a mosquito net is key to getting a restful night’s sleep — and can be an actual lifesaver.

These nets protect people not only from mosquitoes, but the diseases they carry. About half of the world’s population lives in an area where a mosquito bite could lead to malaria. This disease of the blood can lead to fevers, headaches, vomiting, coma, life-threatening complications and death.

Each year, malaria kills about 445,000 people and is especially deadly for young children and pregnant women.

In sub-Saharan Africa alone, the annual economic burden from malaria is $12 billion, which includes the cost of treatment, prevention, missed days of work, and loss of tourism and investment revenue.

The good news is that cheap and portable bed nets are proven to help fight malaria. When four out of five households in a community have nets and use them properly, community members are half as likely to get malaria. This high community use of nets also leads to fewer deaths in children ages 5 and under.

It is important to encourage people to properly use and care for their nets. / Health Communication Capacity Collaborative

These nets are a triple threat to mosquitoes, protecting sleepers by: 1) preventing physical contact between mosquitoes and people, 2) repelling mosquitoes and 3) killing mosquitoes that land on the net.

The nets are made with an insecticide, a type of chemical that is deadly for mosquitoes while safe for people. This insecticide is what makes the nets used in areas with malaria different from the nets you might purchase to go camping in the United States or to decorate a canopy bed.

USAID through the U.S. President’s Malaria Initiative (PMI) has helped distribute more than 268 million insecticide-treated nets in 27 countries since 2005. Thanks in part to these efforts, there has been a three-fold increase in the number of people with access to a net. Since the initiative began, the number of children and pregnant women sleeping under nets has more than doubled in PMI focus countries in sub-Saharan Africa.

Worldwide, treated bed nets were responsible for two-thirds of the 7 million lives saved between 2000 and 2015. We look for these numbers to climb as more people get nets and net technology continues to advance.

A couple in Senegal demonstrates how to correctly tuck in the seams of an treated bednet in order to protect children from mosquito bites. / Maggie Hallahan

Redesigning Nets

It used to be that people had to dip their nets into chemical baths to coat them with insecticide. In the early 2000s, manufacturers started incorporating the insecticide into the fibers of the nets.

Nets, however, cannot continue to be made with the same insecticide and kill as many mosquitoes each year. This is because the mosquitoes that survive landing on the treated nets may pass on that genetic survival trick to their offspring. When subsequent generations of mosquitoes are no longer dying from a certain kind of insecticide, we say that they have become resistant.

This means humans have to stay on their toes and keep coming up with new insecticides or combinations of insecticides in order to keep killing mosquitoes.

The latest technique in fighting resistant mosquitoes is to use the same insecticide, but also weave a new chemical into the net that breaks down the mosquitoes’ ability to resist the insecticide. This kind of net helps better protect people in areas where we have found a lot of resistant mosquitoes.

Looking ahead, scientists are developing new insecticides and combinations of insecticides to put on nets to kill mosquitos and stay ahead of resistance.

Measuring holes in nets is a part of durability monitoring, which studies how nets survive wear and tear over time. / Ana Paula Abìlio

One Tool in the Shed

Even as technology advances, bednets unfortunately don’t last forever. The general rule of thumb is that bednets should be replaced every three years. PMI supports studying the durability of nets so we can better understand how to make them last longer and how often they need to be replaced. We also support teaching people how to take care of their nets and encouraging them to use them properly.

Treated nets are just one tool in PMI’s arsenal in the fight against malaria. In addition to other prevention measures, such as treating walls of homes with mosquito-killing spray, we support medications to protect pregnant women and young children, better blood tests for detecting malaria in patients, and better treatment for those who are found to have malaria.

Using all these tools, in collaboration with our partners, PMI looks forward to achieving a malaria-free world in which we can all sleep easy at night.

To learn more about PMI, please visit www.pmi.gov.

Handing out nets to students through schools is one way USAID increases the number of people using nets. / Riccardo Gangale, VectorWorks Courtesy of Photoshare

About the Author

Bridget Higginbotham is a communications intern with the U.S. President’s Malaria Initiative. Follow them @PMIgov.