Scientific American

Drug-Resistant Malaria Spreads, Scientists Hunt Down Genetic Causes

Thu, 05 Apr 2012 14:20:00 EST

The malaria parasite is a wily organism, shifting its life stages as it flits from human to mosquito and back again. It still kills some 600,000 people each year and has outwitted eradication efforts, having developed resistance to previously popular drugs and, thus far, eluded vaccine-induced immunity.

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Dengue Virus Makes Mosquitoes Better Spreaders

Mon, 02 Apr 2012 20:41:08 EST

The dengue virus depends on mosquitoes to get around. But the virus may have evolved a way to speed its spread--by manipulating the behavior of its mosquito hosts. It makes them more bloodthirsty, and quicker to find a blood meal, than their uninfected counterparts. So says a study in the journal Public Library of Science Pathogens . [Shuzhen Sim, Jose L. Ramirez and George Dimopoulos, " Dengue Virus Infection of the Aedes aegypti Salivary Gland and Chemosensory Apparatus Induces Genes that Modulate Infection and Blood-Feeding Behavior "]

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Wasting Away: Can a Gates Foundation-Funded Toilet-Design Initiative End a Foul Practice in the Developing World?

Tue, 21 Feb 2012 07:00:00 EST

Chances are that if you are reading this, you have a private flush toilet a few steps from your bed. Your commode is more reliable than your mobile connection, and likely will outlast all of your home appliances. Yet huge tracts of the developing world have yet to see so much as a latrine, a situation that facilitates the spread of debilitating or even deadly diarrheal diseases . [More]

New Cornell High-Tech Campus Recalls Former Research Glory of Small New York City Island

Tue, 31 Jan 2012 08:00:00 EST

The aging Goldwater Memorial Hospital on Roosevelt Island--soon to be the site of Cornell University's new NYC Tech Campus --holds a significant place in 20th-century medicine. [More]

Microbes Make Some People Smell Delicious to Mosquitoes

Tue, 03 Jan 2012 20:08:08 EST

Ever wondered why mosquitoes eat some people up but leave others relatively unscathed? A new study finds that this preferential treatment is due to the smells produced by the microscopic critters that cover our bodies. The research is in the journal Public Library of Science ONE . [Niels O. Verhulst et al., " Composition of Human Skin Microbiota Affects Attractiveness to Malaria Mosquitoes "]

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Could Public Health Benefits Make Combating Climate Change Free?

Wed, 21 Dec 2011 14:21:00 EST

DURBAN, South Africa--Former entomologist Diarmid Campbell-Lendrum of the World Health Organization worries about nosebleeds more than the average person. That's because he's one of the estimated 12 million people worldwide afflicted with leishmaniasis --a potentially fatal parasitic disease characterized most often by lesions on the skin and/or mucus membranes--caused by the bite of a sandfly.

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Paul Farmer: International Health Is Equity Issue

Tue, 13 Dec 2011 15:17:08 EST

"In 1983, when I went to Haiti, the wave of sentiment that crashed over me was not just, gosh, this is appalling--it’s unfair."

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World's 10 Worst Toxic Pollution Problems [Slide Show]

Thu, 10 Nov 2011 16:01:00 EST

The price of gold affects more than global finances; it also drives the world's most toxic pollution problem, according to new research from the Blacksmith Institute , an environmental health group based in New York City. Miners in countries from across Africa and Southeast Asia use mercury to separate the precious metal from the surrounding rock and silt. To then separate the resulting amalgam of gold and mercury, heat must be applied to vaporize the mercury. Typically, heating occurs over an open gas flame, releasing the potent neurotoxic element into the atmosphere. What's more, the estimated 10 million to 20 million workers who mine for gold this way will all too often inhale the mercury, putting their health at profound risk.

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Should Scientists Use Genetically Modified Insects to Fight Disease?

Mon, 24 Oct 2011 10:00:00 EST

In the November 2011 issue of Scientific American, author Bijal Trivedi looks at the ongoing controversies surrounding the use of genetically modified mosquitoes to fight dengue fever. We asked biologist Mark Q. Benedict and Helen Wallace, the director of GeneWatch UK , to illuminate the issues surrounding the release of genetically modified insects into the wild.

Genetically Modified Mosquitoes Could Be an Important Tool in the Fight against Disease [More]

The Wipeout Gene (preview)

Mon, 24 Oct 2011 08:00:00 EST

Outside Tapachula, Chiapas, Mexico--10 miles from Guatemala. To reach the cages, we follow the main highway out of town, driving past soy, cocoa, banana and lustrous dark-green mango plantations thriving in the rich volcanic soil. Past the tiny village of Rio Florido the road degenerates into an undulating dirt tract. We bump along on waves of baked mud until we reach a security checkpoint, guard at the ready. A sign posted on the barbed wire–enclosed compound pictures a mosquito flanked by a man and woman: Estos mosquitos genéticamente modificados requieren un manejo especial , it reads. We play by the rules.

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Three Promising Vaccine Strategies against Malaria

Tue, 18 Oct 2011 18:00:00 EST

This graphic originally appeared with the article " Halting the World's Most Lethal Parasite ," in the November 2010 issue of Scientific American . We are posting it as background for today's announcement of good success in a phase III trial using a traditional vaccine by GlaxoSmithKline. Scroll down to see the illustration.

For decades the public health community has tried to devise a vaccine that would confer lifetime immunity against the malaria parasite and help stamp out disease. Yet the effort has always been an exercise in frustration. The complex life cycle of the parasite makes it challenging to know the best way to create an effective vaccine. But the advent of new funding and a spate of innovative ideas have changed the outlook dramatically in recent years. For the first time, a vaccine has reached late-stage clinical trials, and dozens of other ideas are in the early development stage. Three different approaches appear here.

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In the Ink: Do All Tattoo Pigments Use Mercury and Other Toxic Heavy Metals?

Fri, 07 Oct 2011 11:00:00 EST

Dear EarthTalk : I’m interested in getting a new tattoo, but recently found out that red tattoo ink contains mercury. Is this true of other tattoo inks as well? Are there any ecofriendly alternatives? --John P., Racine, Wash.

It is true that some red inks used for permanent tattoos contain mercury, while other reds may contain different heavy metals like cadmium or iron oxide. These metals--which give the tattoo its “permanence” in skin--have been known to cause allergic reactions, eczema and scarring and can also cause sensitivity to mercury from other sources like dental fillings or consuming some fish. While red causes the most problems, most other colors of standard tattoo ink are also derived from heavy metals (including lead, antimony, beryllium, chromium, cobalt nickel and arsenic) and can cause skin reactions in some people. [More]

A Life in Science, with Elizabeth Blackburn

Thu, 06 Oct 2011 14:00:00 EST

Biologist Elizabeth Blackburn grew up in Hobart on the Australian island of Tasmania. It was a long journey from there to a Nobel prize and the lab she runs at the University of California in San Francisco.

Malaria researcher Clare Smith, an early-career scientist who attended this year's Lindau Nobel Laureate Meeting in Germany, is also a Hobart girl, and she's trying to decide whether to follow in Blackburn's footsteps and move overseas after she finishes her PhD.

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Why Is Average IQ Higher in Some Places?

Tue, 06 Sep 2011 16:10:00 EST

Being smart is the most expensive thing we do. Not in terms of money, but in a currency that is vital to all living things: energy. One study found that newborn humans spend close to 90 percent of their calories on building and running their brains. (Even as adults, our brains consume as much as a quarter of our energy.) If, during childhood, when the brain is being built, some unexpected energy cost comes along, the brain will suffer. Infectious disease is a factor that may rob large amounts of energy away from a developing brain. This was our hypothesis, anyway, when my colleagues, Corey Fincher and Randy Thornhill, and I published a paper on the global diversity of human intelligence.

A great deal of research has shown that average IQ varies around the world, both across nations and within them . The cause of this variation has been of great interest to scientists for many years. At the heart of this debate is whether these differences are due to genetics, environment or both.

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Nobel Laureate Peter Agre: From Aquaporins to Lutefisk

Wed, 20 Jul 2011 12:40:08 EST

Peter Agre, 2003 Chemistry Nobel laureate for his work on aquaporins, the proteins that allow water into and out of cells, talks about his research, his upbringing and why he almost ran for the Senate, in a conversation recorded at the Lindau Nobel Laureate Meeting in Lindau, Germany.

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The Civil War and Malaria

Thu, 14 Jul 2011 11:00:00 EST

EDITOR’S NOTE: We now know that a single-celled sporozoan of the Plasmodium genus causes malaria. It was discovered to be a parasite in 1880, by Alphonse Laveran, a French army surgeon in Algeria, and its transmission by the mosquito was first demonstrated in 1897 by Ronald Ross, a British officer in the Indian Medical Service. As you read this article you sense the struggle to understand the parts of the puzzle of this disease (and other diseases transmitted also by mosquitoes and bad hygiene). With our hindsight from 2011 we can quickly grasp that it is the terrain most favorable to mosquitoes that tends to be the most prone to malaria.

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100 Years Ago: Cancer's Roots

Thu, 14 Jul 2011 07:00:00 EST

JULY 1961

Forecasting Revolution [More]

Female Education Reduces Infant and Childhood Deaths

Thu, 07 Jul 2011 11:00:00 EST

The single biggest factor, by far, in reducing the rate of death among children younger than five is greater education for women. In all countries worldwide, whether females increase schooling from 10 years to 11, say, or two years to three, infant mortality declines , according to a recent study by the Institute for Health Metrics and Evaluation at the University of Washington. [More]

Scent of a Human: The Battle against Mosquitoes (preview)

Wed, 15 Jun 2011 07:02:00 EST

Mosquitoes have remarkably refined powers of smell. The insects that spread malaria across sub-Saharan Africa come exquisitely equipped to find human blood. They home in on the scent of human breath and sweat and swiftly insert their needlelike mouthparts into the target’s skin. As they dine, their saliva transmits the malaria parasite into the wound. With a simple bite, they can ultimately take a life.

Other mosquitoes prefer different species--say, cattle or birds. Some, it seems, even favor selected individuals within the target group; certain people at a summer barbeque will be attacked relentlessly, yet others will remain unbitten. And some mosquitoes can identify their victims from more than 165 feet.

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The Nose Knows: How Malaria Mosquitoes Sniff Out Human Targets [Slide Show]

Wed, 15 Jun 2011 07:00:00 EST

Scientists have never fully understood how mosquitoes distinguish the smell of human breath and sweat from other odors in nature. To learn more, molecular biologist John Carlson at Yale University and colleagues relied on a mutant strain of fruit fly. Each of a series of mosquito genes that code for smell receptors was transplanted, individually, into the fruit flies, which have an "empty" smell-detecting neuron lacking smell receptors.

Each gene caused the neuron to produce a single kind of mosquito receptor, which binds to odor molecules that have a particular shape. Carlson's team then presented one kind of odor molecule at a time to the flies. If a receptor grabbed that odorant, the neuron sent a signal to the brain indicating the odor's presence, and an electrode implanted next to the neuron revealed the response.

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