News / Africa

Killing Mosquitoes Early On

A young girl with malaria rests in the inpatient ward of the Malualkon Primary Health Care Center in Malualkon, in the South Sudanese state of Northern Bahr el-Ghazal, June 1, 2012.
A young girl with malaria rests in the inpatient ward of the Malualkon Primary Health Care Center in Malualkon, in the South Sudanese state of Northern Bahr el-Ghazal, June 1, 2012.

Multimedia

Audio
  • Listen to De Capua report on controling mosquitoes with LSM

Joe DeCapua
Targeting mosquitoes in their early stages of life has the potential to greatly boost malaria control efforts and prevent thousands of new infections every year. A new study looks at the effectiveness of – what’s called -- larval source management or LSM. It’s estimated malaria causes 660,000 deaths every year, mostly in sub-Saharan Africa and Asia.


Currently, the main malaria preventive measures are long-lasting insecticide-treated mosquito nets and the indoor spraying of homes. But mosquitoes are building up resistance to the chemicals. That’s one reason why researchers reviewed 13 studies of LSM from Eritrea, Kenya, The Gambia, Mali, Tanzania, the Philippines, Sri Lanka and Greece.

Lucy Tusting -- an epidemiologist at the London School of Hygiene and Tropical Medicine -- is the lead author of what’s called The Cochrane review.

“This research was important because a number of malaria endemic countries in sub-Saharan Africa and elsewhere are currently using larval source management. But there’s a real lack of consensus on how effective the method can be and in which settings it’s appropriate. And few studies have so far been conducted to rigorously evaluate the intervention,” she said.

Eliminating mosquitoes before they’re able to transmit the parasite would – on the surface – appear to be a valuable addition to any control program. But Tusting said it’s not a simple decision.

“First of all, we do have very, very effective existing methods of malaria control. Long-lasting insecticide treated nets and indoor residual spraying are both highly effective, rolled out in a vast scale across Africa and elsewhere. And they’ve been undoubtedly a major reason for the successes in malaria control in the last decades. So I think with that in mind there’s been less need to look at other alternative interventions.”

The World Health Organization has issued guidelines on the use of LSM. Currently, the WHO does not recommend using the larvicides in rural sub-Saharan Africa, unless there are particular circumstances that limit the habitats of mosquito larvae. The guidelines say, “Larviciding should be considered for malaria control -- with or without other interventions -- only in areas where the breeding sites are few, fixed and findable.”

The guidelines add, “In most endemic settings, the appropriate way to use larviciding is as a supplement” to nets and spraying. The WHO says, “Larviciding measures may be effective as the leading method of vector control in urban areas.”  However, it says “more good quality evidence is needed to support this view.”

Tusting explained how larval source management works.

“Malaria is transmitted by mosquitoes,” she said, “The mosquitoes lay their eggs in standing water and the eggs then hatch and develop into larvae, which then develop into flying adult mosquitoes, which are capable of transmitting malaria. So, larval source management is a method of controlling malaria that works by targeting those immature mosquito stages that are found in standing water.”

Long-lasting insecticide treated nets and residual indoor spraying take aim at adult mosquitoes. Tusting said that LSM would be used in combination with these methods, not in place of them. There are several ways of using larval source management, which could be especially effective in urban areas.

“So, for example, by permanently removing standing water – by draining or filling land – or by making temporary changes to mosquito habitats to disrupt their breeding, for example, by clearing drains to improve water flow. Another common method is larviciding in which chemicals or biological larvicides are added to standing water to kill larvae,” she aid.

Tusting said some research indicates the cost of LSM would be comparable to that of nets and spraying. According to the Roll Back Malaria Campaign, the total cost of the global strategy against the disease is between five and six billion dollars a year.

Her colleague and co-author, Durham University Professor Steve Lindsay, called the review a “landmark publication demonstrating that in many places larval source management should be used as a supplementary weapon against malaria.”

The review says LSM, in appropriate settings, could reduce malaria cases by up to 75 percent and the proportion of people infected with the malaria parasite by 90 percent.

You May Like

Video One Year After Thai Coup, No End in Sight for Military Rule

Since carrying out the May 22, 2014 coup, the general has retired from the military but is still firmly in charge More

Video Afghan Economy Sinks As Troops Depart

Afghans are grappling with how exodus will affect country's fragile economy More

Video Scientists Say We Need Softer Robots

Today’s robots are mostly hard, rigid machines, with sharp edges and forceful movements, but researchers at Carnegie Mellon University say they should be softer and therefore safer More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Turkey's Main Opposition Party Hopes for Election Breakthroughi
X
May 22, 2015 10:23 AM
Turkey’s main opposition Republican People’s Party has sought an image change ahead of the June 7 general election. The move comes after suffering successive defeats at the hands of the Islamist-rooted AK Party, which has portrayed it as hostile to religion. Dorian Jones reports from the western city of Izmir.
Video

Video Turkey's Main Opposition Party Hopes for Election Breakthrough

Turkey’s main opposition Republican People’s Party has sought an image change ahead of the June 7 general election. The move comes after suffering successive defeats at the hands of the Islamist-rooted AK Party, which has portrayed it as hostile to religion. Dorian Jones reports from the western city of Izmir.
Video

Video Europe Follows US Lead in Tackling ‘Conflict Minerals’

Metals mined from conflict zones in places like the Democratic Republic of Congo are often sold by warlords to buy weapons. This week European lawmakers voted to force manufacturers to prove that their supply chains are not inadvertently fueling conflicts and human rights abuses. Henry Ridgwell reports from London.
Video

Video Class Tackles Questions of Race, Discrimination

Unrest in some U.S. cities is more than just a trending news item at Ladue Middle School in St. Louis, Missouri. As VOA’s Kane Farabaugh reports, it’s a focus of a multicultural studies class engaging students in wide-ranging discussions about racial tensions and police aggression.
Video

Video Mind-Controlled Prosthetics Are Getting Closer

Scientists and engineers are making substantial advances towards the ultimate goal in prosthetics – creation of limbs that can be controlled by the wearer’s mind. Thanks to sophisticated sensors capable of picking up the brain’s signals, an amputee in Iceland is literally bringing us one step closer to that goal. VOA’s George Putic reports.
Video

Video Afghan Economy Sinks As Foreign Troops Depart

As international troops prepare to leave Afghanistan, and many foreign aid groups follow, Afghans are grappling with how the exodus will affect the country's fragile economy. Ayesha Tanzeem reports from the Afghan capital, Kabul.
Video

Video Poverty, Ignorance Force Underage Girls Into Marriage

The recent marriage of a 17-year old Chechen girl to a local police chief who was 30 years older and already had a wife caused an outcry in Russia and beyond. The bride was reportedly forced to marry and her parents were intimidated into giving their consent. The union spotlighted yet again the plight of many underage girls in developing countries. Zlatica Hoke reports poverty, ignorance and fear are behind the practice, especially in Asia and Africa.
Video

Video South Korea Marks Gwangju Uprising Anniversary

South Korea this week marked the 35th anniversary of a protest that turned deadly. The Gwangju Uprising is credited with starting the country’s democratic revolution after it was violently quelled by South Korea’s former military rulers. But as Jason Strother reports, some observers worry that democracy has recently been eroded.
Video

Video California’s Water System Not Created To Handle Current Drought

The drought in California is moving into its fourth year. While the state's governor is mandating a reduction in urban water use, most of the water used in California is for agriculture. But both city dwellers and farmers are feeling the impact of the drought. Some experts say the state’s water system was not created to handle long periods of drought. Elizabeth Lee reports from Ventura County, an agricultural region just northwest of Los Angeles.
Video

Video How to Clone a Mammoth: The Science of De-Extinction

An international team of scientists has sequenced the complete genome of the woolly mammoth. Led by the Swedish Museum of Natural History in Stockholm, the work opens the door to recreate the huge herbivore, which last roamed the Earth 4,000 years ago. VOA’s Rosanne Skirble considers the science of de-extinction and its place on the planet
Video

Video Blind Boy Defines His Life with Music

Cole Moran was born blind. He also has cognitive delays and other birth defects. He has to learn everything by ear. Nevertheless, the 12-year-old has had an insatiable love for music since he was born. VOA’s June Soh introduces us to the young phenomenal harmonica player.

VOA Blogs