Commentary: More malaria nets likely needed between campaigns

August 27, 2018, Johns Hopkins University Bloomberg School of Public Health
Credit: CC0 Public Domain

A new study published in the Lancet journal EClinicalMedicine suggests that more mosquito nets are likely needed between mass campaigns to keep malaria cases in check. Writing in an accompanying commentary, Johns Hopkins Center for Communication Programs' Hannah Koenker, Ph.D., says the paper shows that the loss of treated bed nets between mass campaigns may have a much greater impact on malaria transmission than previously understood.

The study, conducted by researchers at the Institut Pasteur, looked at net distribution in Madagascar from 2009 to 2015 and found that cases began to rise long before the next campaign could distribute new insecticide-treated bed nets.

Mosquito nets "have never been a perfect tool, but they have worked remarkably well despite their imperfections," Koenker writes in the July 30 publication. "Nonetheless, if we are serious about , it is abundantly clear that more [nets] need to be delivered than we are currently providing." Koenker is director of VectorWorks, a CCP-led program funded by the President's Malaria Initiative (PMI). CCP is based at the Johns Hopkins Bloomberg School of Public Health.

Treated are thought to be responsible for the lion's share of the reduction in malaria cases worldwide since 2000. In 2015, there were roughly 212 million malaria cases and an estimated 429,000 malaria deaths worldwide, according to the World Health Organization.

Typically, are distributed in universal mass distribution campaigns, which take place approximately every three years. The expectation has been that the nets will continue to be effective until the next campaign is held. Nets wear out for a number of reasons: They may be torn, washed too often, given to someone else who may seem to be in greater need and more. It is nearly impossible to even buy a replacement net. Koenker says 50 percent or more of nets wear out by the time the next campaign rolls around.

In several countries, the President's Malaria Initiative-sponsored VectorWorks, which Koenker leads, has successfully piloted continuous distribution approaches as an alternative or supplement to mass campaigns held every three years. In Tanzania, this is done through annual school-based campaigns where children receive nets, providing access for the entire household. In Madagascar, CCP and its partners implemented a continuous distribution program using community health workers and religious leaders in the Toamasina district on the East Coast from Sept. 2013 to June 2014, making additional nets available to those who needed them, when they needed them.

The Institut Pasteur researchers found that for the first year after a mass in Madagascar, almost none of the three dozen health centers where data was collected reported a malaria alert. In year two, 43 percent of sites had alerts, while in the third year, 68.5 percent of the sites reported alerts. Alerts were triggered when the sites experienced a substantial increase in malaria cases for three weeks straight.

The exception was in Toamasina, where replacement nets were available to community members. The number of weekly malaria cases decreased by 14 percent when continuous distribution was available. By contrast, those sites without continuous distribution saw a 12 percent increase in malaria over the same period. (Following the Toamasina success, the program was scaled up to additional districts. Continuous community distribution will be in place in 20 districts in Madagascar by the end of this year.)

"Nets wear out," Koenker says. "We were hoping there would be no impact on transmission, but now we see that we can't just keep doing what we have been doing. This study tells us we need these types of continuous net channels to ensure people can access that work, year after year. Now, the question is: What is the most efficient way to maintain high access?"

"More is More: Are We Delivering Enough LLINs?" was written by Hannah Koenker.

Explore further: A plan to distribute insecticide-treated bed nets annually to children in schools

More information: Hannah Koenker, More is More: Are We Delivering Enough LLINs?, EClinicalMedicine (2018). DOI: 10.1016/j.eclinm.2018.07.005

Related Stories

A plan to distribute insecticide-treated bed nets annually to children in schools

July 11, 2018
Insecticide-treated bed nets—a crucial part of malaria protection throughout sub-Saharan Africa and regions of Asia—have long been distributed to people who need them through mass campaigns conducted every three years.

New type of bed net could help fight against malaria

August 11, 2018
A new type of bed net could prevent millions of cases of malaria, according to new research published in The Lancet today.

Flood-hit Niger launches campaign to fight malaria

September 8, 2017
Niger has launched a campaign to destroy mosquito breeding sites in the capital in the wake of heavy rains that have lashed the city since June.

Combining insecticide sprays and bed nets 'no more effective' in cutting malaria

December 8, 2014
There is no need to spray insecticide on walls for malaria control when people sleep under treated bed nets, according to new research.

Study finds use of bed nets by 75 percent of population could eradicate malaria

March 7, 2013
Malaria, the leading cause of death among children in Africa, could be eliminated if three-fourths of the population used insecticide-treated bed nets, according to a new study from the National Institute for Mathematical ...

Recommended for you

Medical marijuana might help MS patients, but uncertainty remains

October 13, 2018
Medical products derived from marijuana might have a mild benefit in treating symptoms of multiple sclerosis, based on reports from patients.

Do not give decongestants to young children for common cold symptoms, say experts

October 11, 2018
Decongestants should not be given to children under 6—and given with caution in children under 12—as there is no evidence that they alleviate symptoms such as a blocked or runny nose, and their safety is unclear, say ...

New techniques can detect Lyme disease weeks before current tests

October 11, 2018
Researchers have developed techniques to detect Lyme disease bacteria weeks sooner than current tests, allowing patients to start treatment earlier.

Pneumonia-causing bacteria can be spread by nose picking and rubbing

October 11, 2018
Pneumonia-causing bacteria can be spread through picking and rubbing the nose, according to new research published in the European Respiratory Journal.

Plant compound found to have therapeutic effect on complications from snakebites

October 11, 2018
Rutin, a flavonoid, may complement antivenom as an effective co-treatment for envenoming from Bothrops jaraca.

Photoactive bacteria bait may help in fight against MRSA infections

October 11, 2018
Purdue University researchers are testing whether a light-active version of heme, the molecule responsible for transporting oxygen in blood circulation, may help people infected with MRSA.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.