The Olympic and Paralympic Games probably won’t further the international spread of Zika virus, the World Health Organization concluded in a news conference June 14.
Data from past events, including previous Olympics and World Cup tournaments, suggest that mass gatherings don’t greatly increase the spread of diseases. In addition, the 2016 Olympics will take place in August during Brazil’s winter months, when mosquito-borne diseases aren’t so rampant. Brazil also is stepping up efforts to curb mosquito populations. According to WHO, both factors are likely to reduce Zika transmission during the games.
“Everything is being done to minimize what is already a low risk,” said Bruce Aylward, who heads WHO’s division on outbreaks and health emergencies.
Not all scientists are convinced. More than 200 scientists and doctors have now signed an open letter to WHO’s director calling for postponing the Olympics and Paralympics or moving them from Rio de Janeiro.
BOSTON — Moms get blamed for a lot — including their kids’ cavities. But new data show that the most common cause of tooth decay, the bacterium Streptococcus mutans, doesn’t always come from mother-to-child transmission.
Researchers from the University of Alabama at Birmingham studied 119 children in rural Alabama and 414 of their household contacts, tracking the path of S. mutans. Contrary to expectation, 40 percent of the children did not share any strains with their mothers. Instead, those strains usually overlapped with those of siblings and cousins. And 72 percent of children carried a strain of S. mutans that no one else in the family had, probably picked up from other children at school, day care or other locations. The research was presented June 17 at ASM Microbe 2016, a meeting of the American Society for Microbiology and the Interscience Conference on Antimicrobial Agents and Chemotherapy.
While maternal transmission was still the most common route, “we’re not trying to say ‘Don’t kiss your babies,’” said Stephanie Momeni, a doctoral candidate at UAB. Rather, the ultimate goal of the research is to learn whether particular strains of S. mutans pose a greater hazard for dental health. Knowing that would help identify children who might be in need of more aggressive dental hygiene.
Driverless cars are revved up to make getting from one place to another safer and less stressful. But clashing views over how such vehicles should be programmed to deal with emergencies may stall the transportation transformation, a new study finds.
People generally approve of the idea of automated vehicles designed to swerve into walls or otherwise sacrifice their passengers to save a greater number pedestrians, say psychologist Jean-François Bonnefon of the Toulouse School of Economics in France and his colleagues. But here’s the hitch: Those same people want to ride in cars that protect passengers at all costs, even if pedestrians end up dying, the researchers report in the June 24 Science. “Autonomous cars can revolutionize transportation,” says cognitive scientist and study coauthor Iyad Rahwan of the University of California, Irvine and MIT. “But they pose a social and moral dilemma that may delay adoption of this technology.”
Such conflict puts makers of computerized cars in a tough spot, Bonnefon’s group warns. Given a choice between driverless cars programmed for the greater good or for self-protection, consumers will overwhelmingly choose the latter. Regulations to enforce the design of passenger-sacrificing cars would backfire, the scientists suspect, driving away potential buyers. If so, plans for easing traffic congestion, reducing pollution and eliminating many traffic accidents with driverless cars would be dashed. Further complicating matters, the investigators say, automated vehicles will need to respond to emergency situations in which an action’s consequences can’t be known for sure. Is it acceptable, for instance, to program a car to avoid a motorcycle by swerving into a wall, since the car’s passenger is more likely to survive a crash than the motorcyclist?
“Before we can put our values into machines, we have to figure out how to make our values clear and consistent,” writes Harvard University philosopher and cognitive scientist Joshua Greene in the same issue of Science. But moral dilemmas have long dogged human civilizations and are sometimes unavoidable, says psychologist Kurt Gray of the University of North Carolina in Chapel Hill. People may endorse conflicting values depending on the situation — say, saving others when taking an impersonal perspective and saving oneself when one’s life is on the line.
Workable compromises can be reached, Gray says. If all driverless cars are programmed to protect passengers in emergencies, automobile accidents will still decline, he predicts. Despite being a danger to pedestrians on rare occasions, those vehicles “won’t speed, won’t drive drunk and won’t text while driving, which would be a win for society.”
Bonnefon’s team examined attitudes toward driverless vehicles in six online surveys conducted between June and November 2015. A total of 1,928 U.S. participants completed surveys.
Participants generally disapproved of automated vehicles sacrificing a passenger to save one pedestrian, but approval rose sharply with the number of pedestrians’ lives that could be saved. For instance, about three-quarters of volunteers in one survey said it was more moral for an automated car to sacrifice one passenger rather than kill 10 pedestrians. That trend held even when volunteers imagined they were in a driverless car with family members.
Bonnefon doubts those participants were simply trying to impress researchers with “noble” answers. But opinions changed when participants were asked about their views of driverless cars in actual practice. Responders to another survey similarly rated pedestrian-protecting automated cars as more moral, but most of those same people readily admitted that they wanted passenger-protecting cars for themselves. Other participants considered driverless cars that swerved to avoid pedestrians as good for others to drive but had little intention to buy one.
Volunteers expressed weak support for a law forcing either human drivers or automated cars to swerve to avoid pedestrians. Even in a hypothetical case where a passenger-sacrificing automated car saved the lives of 10 pedestrians, participants rated their willingness to have such sacrifices legally enforced at only 40 on a scale of 0 to 100. A final survey found that participants were much less likely to consider buying driverless cars subject to pedestrian-protecting regulations after being presented with situations in which they were riding alone, with an unspecified family member or with their child.
Fire was one of our ancient ancestors’ first forays into technology. Controlled burns enabled early hominids to ward off cold, cook and better preserve game. New evidence places fire-making in Europe as early as 800,000 years ago, much earlier than previously thought and closer to scientists’ best estimate for hominids’ first use of fire, about 1 million years ago in Africa.
It’s unclear how early Homo species came to master fire, but it was perhaps an attempt at problem solving — capturing a natural phenomenon and harnessing it for use. That tradition has persisted in human cultures. It thrives today among scientists, especially those engaged in problem solving related to society’s most pressing issues. Take drug addiction, a vexing problem that has grown in urgency in the last decade as more and more people have become dependent on opioids — not only street drugs like heroin but also prescription pain meds like OxyContin and fentanyl. Opioids can be extremely difficult to give up because of their strong addictive pull. So scientists are trying to develop vaccines that would block the effects of heroin and other drugs of abuse, as Susan Gaidos reports. Eliciting a strong immune response, researchers theorize, could stop the drug from reaching the brain, preventing the high that fuels addiction. Success with such biotechnology, now being tested only in lab animals, would offer hope to many battling to stay off drugs.
Another modern scourge is terrorism, and anthropologists like Scott Atran have been exploring the psychological and cultural factors that drive some individuals to extreme acts of violence. There is no technology to prevent people from committing such acts — at least not yet. Basic explorations must always precede any practical use of new knowledge: Hominids could not use fire until they understood its nature and limits — which things burn, which do not; water and sand douse flame, oil and fat fuel it. Mapping terrorism’s contours is just a beginning on a long journey toward developing tactics for undercutting its power.
So it is with many other reports in this issue about basic explorations that may well precede the birth of new technologies. A few favorites:
A report on insights into how the microbial denizens of the gut influence weight gain and obesity. Scientists have now revealed a molecule made by microbes that sends a signal to the brain, influencing fat storage and appetite.
An intriguing study of mice with genetic mutations similar to those found in some people with autism. The findings suggest a role in the disorder for nerve cells involved with touch, as well as a new way to think about autism that may one day identify a target for novel therapies and interventions.
News of a second detection of gravitational waves from LIGO. It’s less dramatic and showy than the first black hole merger detection, announced in February. But it is nonetheless a further sign that a new era, one in which astronomers probe the heavens by watching for violent if subtle wakes in the fabric of spacetime, is upon us.
Feeling good may help the body fight germs, experiments on mice suggest. When activated, nerve cells that help signal reward also boost the mice’s immune systems, scientists report July 4 in Nature Medicine. The study links positive feelings to a supercharged immune system, results that may partially explain the placebo effect.
Scientists artificially dialed up the activity of nerve cells in the ventral tegmental area — a part of the brain thought to help dole out rewarding feelings. This activation had a big effect on the mice’s immune systems, Tamar Ben-Shaanan of Technion-Israel Institute of Technology in Haifa and colleagues found.
A day after the nerve cells in the ventral tegmental area were activated, mice were infected with E. coli bacteria. Later tests revealed that mice with artificially activated nerve cells had less E. coli in their bodies than mice without the nerve cell activation. Certain immune cells seemed to be ramped up, too. Monocytes and macrophages were more powerful E. coli killers after the nerve cell activation.
If a similar effect is found in people, the results may offer a biological explanation for how positive thinking can influence health.
The family of known dwarf planets orbiting the sun just got a new member. The tiny world, designated 2015 RR245, lives in the Kuiper belt, the icy debris field beyond Neptune that’s home to Pluto. RR245 is currently about 9.6 billion kilometers from the sun, or roughly 64 times as far as Earth, and it loops around the sun on an elongated orbit every 700 years or so.
Astronomers first noticed RR245 in February as a drifting speck of light in images taken last September at the Canada-France-Hawaii telescope in Hawaii. The planet’s size is hard to determine without knowing how reflective its surface is; it could be large and dark or tiny and bright. But if its surface is similar to other worlds in the Kuiper belt, then RR245 might be about 700 kilometers wide, just one-fifth the diameter of the moon.
Within the next couple of years, the epidemic that has battered the region since 2015 will largely be over, researchers estimate in a paper online July 14 in Science.
“If we’re not past the peak already, we’re very close to it,” says study coauthor Neil Ferguson of Imperial College London. After this outbreak winds down, it may be a decade — at least — before another large-scale Zika epidemic hits the region. The new timeline could help vaccine researchers get a jump on future outbreaks, and might make health officials rethink advice to pregnant women trying to avoid Zika-related birth defects. Ferguson’s work also suggests something counterintuitive: Current efforts to kill Zika-carrying mosquitoes might actually make it easier for the virus to reemerge.
“It’s an important and timely analysis,” says infectious disease researcher Oliver Pybus of the University of Oxford. “Policy makers would be wise to read it carefully.”
Brazil reported the first cases of Zika in May 2015. Since then, the mosquito-borne virus has spread to 48 countries. Scientists have now widely accepted Zika as a cause of microcephaly, a devastating birth defect that leaves babies with shrunken heads and brains, as well as other serious problems (SN Online: 6/28/16).
Scientists and health officials have hustled to fight Zika, but they’ve had trouble keeping up. Mosquito-control efforts haven’t helped much, says Ferguson, and a safe and effective vaccine could still be years away. What’s more, advice to postpone pregnancy isn’t always realistic, he says.
Predicting the epidemic’s course could refine current Zika-fighting strategies. Ferguson and colleagues made a computer simulation of Zika transmission within Latin America, using data from 35 countries that have reported cases. The team factored in such variables as seasonal climate variation, the ease with which Zika jumps from person to mosquito to person, and human travel patterns between countries.
After the current outbreak ends, simulations show that some 30 years could pass before Zika transmission picks up again. Once infected with Zika, people are immune to the virus, Ferguson says, capping an epidemic’s length and buying some time before a resurgence. He can’t say for sure that another major outbreak is still three decades away — but suspects a lull could last at least one decade.
Zika has “been burning through the population,” Ferguson says. “Sooner or later, it starts to run out of people to infect.”
The virus doesn’t need to infect everybody to peter out — just enough to generate herd immunity. At that point, so many people are immune to Zika that it can’t easily spread, protecting those still uninfected.
Killing mosquitoes — a strategy some countries have used to curb Zika’s reach — could actually hinder herd immunity, letting the next epidemic strike sooner, the team’s simulations suggest. With mosquito control that’s only marginally effective, a second wave of Zika hits about five years earlier than with no mosquito control at all, the simulations indicate.
“It makes sense theoretically,” says epidemiologist Mikkel Quam of Umeå University in Sweden. But considering that the cost of herd immunity might be more babies born with birth defects, he says, “any way to reduce infection is worth doing now, even if it means potentially more epidemics in years to come.”
Immunity to Zika could pose problems for vaccine development, Ferguson says. By the time researchers have something that’s safe to use, it will be hard to find a group of people to test it in. “This was a problem at the end of the Ebola epidemic as well,” he says.
Still, Ferguson says it’s an opportunity to think creatively. In the future, for instance, researchers could prequalify trial sites and get clinicians on the ground early, so when (and if) Zika hits somewhere else, say southeast Asia, they’re ready to go.
He also thinks his simulation could help health officials more clearly lay out the risks to pregnant women. Though the epidemic in Latin America will last roughly three years, his team estimates, individual outbreaks within the region can taper off after three to six months.
By tailoring recommendations to different locations, officials could limit the period of time they’re advising women to delay pregnancy.
When a honeybee colony gets hot and bothered, the crisis sets tongues wagging. Middle-aged bees stick their tongues into the mouths of their elders, launching these special drinker bees to go collect water. That’s just one detail uncovered during a new study of how a colony superorganism cools in hot weather.
Using lightbulbs to make heat waves in beehives, researchers have traced how honeybees communicate about collecting water and work together in deploying it as air-conditioning. The tests show just how important water is for protecting a colony from overheating, Thomas Seeley of Cornell University and his colleagues report online July 20 in the Journal of Experimental Biology. Water collection is an aspect of bee biology that we know little about, says insect physiologist Sue Nicolson of the University of Pretoria in South Africa. Collecting pollen and nectar have gotten more attention, perhaps because honeybees store them. Water mostly gets picked up as needed.
Bees often get as much water as they need in the nectar they sip. But they do need extra water at times, such as during overheating in the center of the nest where eggs and young are coddled. When researchers artificially heated that zone in two colonies confined in a greenhouse, worker bees fought back. They used their wings to fan hot air out of the hive. “You can put your hand in the opening of a hive on a hot day and feel the blast of air that’s being pushed out,” Seeley says. Several hundred bees also moved out of the nest to cluster in a beardlike mass nearby. Their evacuation reduces body heat within the nest and opens up passageways for greater airflow, he says.
The bees also had a Plan C — evaporative cooling. Middle-aged bees inside a hive walked toward the nest entrance to where a small number of elderly bees, less than 1 percent of the colony, hang out and wait until water is needed. Heat by itself doesn’t activate these bees, especially since they’re not in the overheating core. Seeley now proposes that the burst of middle-aged bees’ repeated begging for water by tongue extension eventually sends the water-collecting bees into action. They return carrying some 80 percent of their weight in water. “The water carrier comes in looking really fat, and the water receivers start out looking very skinny,” Seeley says. “Over a minute when the transfer takes place, their forms reverse.” Then the receiving bees go to the hot zone, regurgitate their load of water and use their tongues to spread it over the fevered surfaces.
In a water-deprivation experiment, bees prevented from gathering water could not prevent temperatures from rising dangerously, up to 44° Celsius, in their hive. When researchers permitted water-collector squadrons to tank up again, colonies could control temperatures. Even for multitalented bees, water is necessary for cooling, the researchers conclude.
After a severe heat stress, the researchers noticed some bees with plumped-up abdomens hanging inside the colony. “Sometime they would be lined up like bottles of beer in the refrigerator,” Seeley says. Bottled beverages is what they were, he argues, storing water and remaining available if the coming night proved as water-stressed as the day.
“Honeybees continue to amaze,” says Dennis vanEngelsdorp of the University of Maryland in College Park, who studies bee health. “Even after centuries of study, we have something new.”
Boeing Milestones of Flight Hall Now open After two years of renovations, some of the museum’s most cherished artifacts — including the Spirit of St. Louis and an Apollo Lunar Module — are now on display alongside new objects, including a studio model of the Starship Enterprise.
National Air & Space Museum, Washington, D.C. Pterosaurs: Flight in the Age of Dinosaurs Through October 2 Fossils, life-size models and a virtual flight lab transport visitors back to the time of these ancient fliers.
Natural History Museum of Los Angeles County DARPA: Redefining Possible Through September 5 In this hands-on exhibit, see a humanlike robot, prosthetic arm, robotic exoskeleton and other high-tech innovations developed by the U.S. Defense Advanced Research Projects Agency over the last six decades.
Like botanical vampires, dodder plants (Cuscuta sp.) suck the life out of crops around the world. But tomatoes (Solanum lycopersicum) are mysteriously immune to the parasitic vine’s attacks.
To figure out how they do it, a research team from England and Germany hit tomatoes and three other plant species with C. reflexa extract in the lab. Tomatoes totally overreacted, producing stress hormones to protect themselves from the parasite, while the other plants failed to mount a defense.
This suggests that tomatoes treat the dodder like a virus, taking cues from parasite proteins as a warning system, the team writes July 28 in Science. This sensitivity traces to a receptor that senses the presence of a small protein released by dodder plants.
This probably isn’t the only defense option. Some wild tomato species can fend off dodder even though they’re missing the gene behind the receptor, the researchers note. Still, the findings could prove useful in protecting other crops from vampiric vines through genetic engineering.
