News / Science & Technology

Study: Mosquitoes Can Smell Malaria

FILE - Scientists collected odor compounds in glass jars from malaria-infected mice. (Credit: Nick Sloff, De Moraes & Mescher Research Group)
FILE - Scientists collected odor compounds in glass jars from malaria-infected mice. (Credit: Nick Sloff, De Moraes & Mescher Research Group)

Malaria infection makes mice smell a bit better to mosquitoes, raising the odds that they’ll be bitten and spread the disease. That’s according to a new study in the Proceedings of the National Academy of Sciences.

The research could point the way to a Breathalyzer-style diagnostic test for malaria infection.

And it’s the latest example of how parasites manipulate the creatures they infect for their own nefarious aims.

Penn State University biologist Mark Mescher has seen it before. But not in people, in squash.

When squash plants are infected with cucumber mosaic virus, they produce chemicals that attract aphids. The aphids pick up the virus when they come to the plant for the advertised meal.

The virus even goes an extra step: It makes the plant less nutritious to the insects. After a few bites, Mescher said, the aphids “don’t like the plant very much. So, rather than staying there for the long term they move on and go to the next plant,” spreading the virus with them.

Mescher wondered if something similar was happening with malaria. A couple of studies in people and birds have suggested mosquitoes prefer the malaria-infected over the uninfected. But the studies did not explain why.

Eau de mouse

Mescher and his colleagues found that they could get the same tantalizing effect in malaria-infected mice. Given a choice, about 60 percent of the mosquitoes in their experiment were drawn to an infected mouse, while around 40 percent went for the uninfected.

The mice didn't even need to be there. The scientists collected the volatile chemicals wafting off infected and uninfected mice and let mosquitoes smell it. Eau de infected mouse had the about same attractive effect as an actual infected mouse.

The researcher found a handful of chemicals in the mouse-odor cocktail that were at higher levels in infected animals than healthy ones. A dab of those chemicals would make even a healthy mouse more appealing to mosquitoes.

“The malaria parasite is enhancing the odor cues the mosquito is already using to find their host,” Mescher said, which helps the parasite hitch a ride to the next victim.

Malaria breathalyzer

Knowing what the mosquitoes are smelling could help identify people who are carrying the malaria parasite but don’t know it.

“It would be nice to have biomarkers that you could use to identify infected individuals that are not actually sick with malaria, or have asymptomatic infections, but are still capable of transmitting the disease,” Mescher said.

It’s a long way off, he added, but, “If you can identify a chemical signature of infection, then you could imagine something like a Breathalyzer, or something along those lines, that would be quick and easy to get the sample and analyze right there in the field.”

“The question is whether it will go beyond solving the mouse malaria problem and get on to the people malaria problem,” joked Peter Hotez, dean of tropical medicine at Baylor College of Medicine.

Parasite manipulation

Hotez noted that malaria is not the only parasite that tweaks the animal it infects in order to improve the odds for its offspring.

A germ called Toxoplasma gondii needs to infect a cat as part of its life cycle. Mice infected with Toxoplasma conveniently lose their fear of cats.

“The way [the germ] propagates itself is by getting eaten and infecting the new animal,” Hotez explained. “It’s a very innovative story that’s emerging in the biology of the host-parasite relationship.”  

Innovative ... and a bit creepy.

You May Like

Katrina Brought Enduring Changes to New Orleans

The city’s recovery is the result of the people and culture the city is famous for, as well as newcomers and start-up industries More

China to Open Stock Markets to Pension Funds

In unprecedented move, government to soon allow local pension funds to invest up to $94 billion in domestic shares More

1 Billion People Used Facebook on Single Day

Facebook CEO Mark Zuckerberg praised the accomplishment in a posting on the social media site More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Colombians Flee Venezuela as Border Crisis Escalatesi
X
August 27, 2015 2:08 AM
Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Colombians Flee Venezuela as Border Crisis Escalates

Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Is China's Economic Data Accurate?

Some investors say China's wild stock market gyrations have been made worse by worries about the reliability of that nation's economic data. And some critics say the reports can mislead investors by painting an unrealistically-strong picture of the economy. A key China scholar says Beijing is not fudging ((manipulating)) the numbers, but that the economy is evolving quickly from smoke-stack industries to services, and the ways of tracking new economic activity are falling behind the change. V
Video

Video Next to Iran, Climate at Forefront of Obama Agenda

President Barack Obama this week announced new initiatives aimed at making it easier for Americans to access renewable energy sources such as solar and wind. Obama is not slowing down when it comes to pushing through climate change measures, an issue he says is the greatest threat to the country’s national security. VOA correspondent Aru Pande has more from the White House.
Video

Video Shipping Containers Provide Experimental Housing

Housing prices around the San Francisco Bay area are out of reach for many people, so some young entrepreneurs, artists and tech industry workers are creating their own houses using converted shipping containers. But as VOA's Mike O’Sullivan reports from Oakland, the effort requires ingenuity and dealing with restrictive local laws.
Video

Video Arctic Draws International Competition for Oil

A new geopolitical “Great Game” is underway in earth’s northernmost region, the Arctic, where Russia has claimed a large area for resource development and President Barack Obama recently approved Shell Oil Company’s test-drilling project in an area under U.S. control. Greg Flakus reports.
Video

Video Philippine Maritime Police: Chinese Fishermen a Threat to Country’s Security

China and the Philippines both claim maritime rights in the South China Sea.  That includes the right to fish in those waters. Jason Strother reports on how the Philippines is catching Chinese nationals it says are illegal poachers. He has the story from Palawan province.
Video

Video Technique May Eliminate Drill-and-Fill Dental Care

Many people dread visiting dentists because they're afraid of drills. Now, however, a technology developed by a British firm promises to eliminate the need for mechanical cleaning of dental cavities by speeding a natural process of tooth repair. VOA’s George Putic reports.
Video

Video China's Spratly Island Building Said to Light Up the Night 'Like A City'

Southeast Asian countries claim China has illegally seized territory in the Spratly islands. It is especially a concern for a Philippine mayor who says Beijing is occupying parts of his municipality. Jason Strother reports from the capital of Palawan province, Puerto Princesa.
Video

Video Ages-old Ice Reveals Secrets of Climate Change

Ice caps don't just exist at the world's poles. There are also tropical ice caps, and the largest sits atop the Peruvian Andes - but it is melting, quickly, and may be gone within the next 20 years. George Putic reports scientists are now rushing to take samples to get at the valuable information about climate change locked in the ice.
Video

Video French Experiment in Integrating Roma Under Threat

Plans to destroy France’s oldest slum have sparked an outcry on the part of its Roma residents. As Lisa Bryant reports from the Paris suburb of La Courneuve, rights groups argue the community is a fledgling experiment on integrating Roma who are often outcasts in many parts of Europe.
Video

Video Kenyans Turn to Agriculture for Business

Each year Kenyan universities continue to churn out graduates for the job market despite the already existing high rate of unemployment among youth in the country. Some of these young men and women have realized that agriculture can be as rewarding as any other business or job, and they are resorting to agribusiness in large numbers as a way of tackling unemployment. Rael Ombuor reports for VOA.
Video

Video First Women Graduate Elite Army Ranger School

Two women are making history for the U.S. Army by proving they are among the toughest of the tough. VOA's Carla Babb reports from Fort Benning, Georgia as 94 men and those two women rise as graduates of the difficult Ranger school.

VOA Blogs