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The World Mosquito Program (WMP), a nonprofit that pioneered this technique, had run small pilot studies in Australia that suggested it could work. Utarini, who co-leads WMP Yogyakarta, has now shown conclusively that it does.

The team divided a large portion of the city into 24 zones and released Wolbachia-infected mosquitoes in half of them. Almost 10,000 volunteers helped distribute egg-filled containers to local backyards. Within a year, about 95 percent of the Aedes mosquitoes in the 12 release zones harbored Wolbachia.

Wolbachia was first discovered in 1924, in a different species of mosquito. At first, it seemed so unremarkable that scientists ignored it for decades. But starting in the 1980s, they realized that it has an extraordinary knack for spreading. It passes down mainly from insect mothers to their children, and it uses many tricks to ensure that infected individuals are better at reproducing than uninfected ones. To date, it exists in at least 40 percent of all insect species, making it one of the most successful microbes on the planet.

Carried around the world aboard slave ships, Aedes aegypti has thrived. It is now arguably the most effective human-hunter on the planet, its senses acutely attuned to the carbon dioxide in our breath, the warmth of our bodies, and the odors of our skin.

The team found that just 2.3 percent of feverish people who lived in the Wolbachia release zones had dengue, compared with 9.4 percent in the control areas. Wolbachia also seemed to work against all four dengue serotypes, and reduced the number of dengue hospitalizations by 86 percent.

Even then, these already remarkable numbers are likely to be underestimates. The mosquitoes moved around, carrying Wolbachia into the 12 control zones where no mosquitoes were released. And people also move: They might live in a Wolbachia release zone but be bitten and infected with dengue elsewhere. Both of these factors would have worked against the trial, weakening its results

The Wolbachia method does have a few limitations. The bacterium takes months to establish itself, so it can’t be “deployed to contain an outbreak today,” Vazquez-Prokopec told me. As the Yogyakarta trial showed, it works only when Wolbachia reaches a prevalence of at least 80 percent, which requires a lot of work and strong community support

The method has other benefits too. It is self-amplifying and self-perpetuating: If enough Wolbachia-infected mosquitoes are released initially, the bacterium should naturally come to dominate the local population, and stay that way. Unlike insecticides, Wolbachia isn’t toxic, it doesn’t kill beneficial insects (or even mosquitoes), and it doesn’t need to be reapplied, which makes it very cost-effective.

An analysis by Brady’s team showed that it actually saves money by preventing infections

Wolbachia also seems to work against the other diseases that Aedes aegypti carries, including Zika and yellow fever. It could transform this mosquito from one of the most dangerous species to humans into just another biting nuisance.

“Reciprocal Biomimicry Initiative.” The idea is to leverage human technology for the benefit of animals for a change.

The star attraction, arguably, is GPS for birds.

Keats is suggesting specially-designed shell coverings boasting urban colors and visual patterns to help them avoid notice.

The starting point for appreciating that there is a distinctive part of our psychology for morality is seeing how moral judgments differ from other kinds of opinions we have on how people ought to behave.

Moralization is a psychological state that can be turned on and off like a switch, and when it is on, a distinctive mind-set commandeers our thinking. This is the mind-set that makes us deem actions immoral (“killing is wrong”), rather than merely disagreeable (“I hate brussels sprouts”), unfashionable (“bell-bottoms are out”) or imprudent (“don’t scratch mosquito bites”).

The first hallmark of moralization is that the rules it invokes are felt to be universal

Many of these moralizations, like the assault on smoking, may be understood as practical tactics to reduce some recently identified harm. But whether an activity flips our mental switches to the “moral” setting isn’t just a matter of how much harm it does

We all know what it feels like when the moralization switch flips inside us — the righteous glow, the burning dudgeon, the drive to recruit others to the cause.

The human moral sense turns out to be an organ of considerable complexity, with quirks that reflect its evolutionary history and its neurobiological foundations.

At the same time, many behaviors have been amoralized, switched from moral failings to lifestyle choices. They include divorce, illegitimacy, being a working mother, marijuana use and homosexuality.

This wave of amoralization has led the cultural right to lament that morality itself is under assault, as we see in the group that anointed itself the Moral Majority. In fact there seems to be a Law of Conservation of Moralization, so that as old behaviors are taken out of the moralized column, new ones are added to it.

Much of our recent social history, including the culture wars between liberals and conservatives, consists of the moralization or amoralization of particular kinds of behavior.

People don’t generally engage in moral reasoning, Haidt argues, but moral rationalization: they begin with the conclusion, coughed up by an unconscious emotion, and then work backward to a plausible justification.

When psychologists say “most people” they usually mean “most of the two dozen sophomores who filled out a questionnaire for beer money.” But in this case it means most of the 200,000 people from a hundred countries who shared their intuitions on a Web-based experiment conducted by the psychologists Fiery Cushman and Liane Young and the biologist Marc Hauser. A difference between the acceptability of switch-pulling and man-heaving, and an inability to justify the choice, was found in respondents from Europe, Asia and North and South America; among men and women, blacks and whites, teenagers and octogenarians, Hindus, Muslims, Buddhists, Christians, Jews and atheists; people with elementary-school educations and people with Ph.D.’s.

Joshua Greene, a philosopher and cognitive neuroscientist, suggests that evolution equipped people with a revulsion to manhandling an innocent person. This instinct, he suggests, tends to overwhelm any utilitarian calculus that would tot up the lives saved and lost

the findings corroborate Greene’s theory that our nonutilitarian intuitions come from the victory of an emotional impulse over a cost-benefit analysis.

Globally, the numbers can be even worse, and the stakes often higher. “Say a person comes into the hospital in Sierra Leone with a fever and flulike symptoms,” DeRisi says. “After a few days, or a week, they die. What caused that illness? Most of the time, we never find out. Because if the cause isn’t something that we can culture and test for” — like hepatitis, or strep throat — “it basically just stays a mystery.”

It would be better, DeRisi says, to watch for rare cases of mystery illnesses in people, which often exist well before a pathogen gains traction and is able to spread.

Based on a retrospective analysis of blood samples, scientists now know that H.I.V. emerged nearly a dozen times over a century, starting in the 1920s, before it went global.

Zika was a relatively harmless illness before a single mutation, in 2013, gave the virus the ability to enter and damage brain cells.

The beauty of this approach” — running blood samples from people hospitalized all over the world through his system, known as IDseq — “is that it works even for things that we’ve never seen before, or things that we might think we’ve seen but which are actually something new.”

In this scenario, an undiscovered or completely new virus won’t trigger a match but will instead be flagged. (Even in those cases, the mystery pathogen will usually belong to a known virus family: coronaviruses, for instance, or filoviruses that cause hemorrhagic fevers like Ebola and Marburg.)

And because different types of bacteria require specific conditions in order to grow, you also need some idea of what you’re looking for in order to find it.

The same is true of genomic sequencing, which relies on “primers” designed to match different combinations of nucleotides (the building blocks of DNA and RNA).

Even looking at a slide under a microscope requires staining, which makes organisms easier to see — but the stains used to identify bacteria and parasites, for instance, aren’t the same.

The practice that DeRisi helped pioneer to skirt this problem is known as metagenomic sequencing

Unlike ordinary genomic sequencing, which tries to spell out the purified DNA of a single, known organism, metagenomic sequencing can be applied to a messy sample of just about anything — blood, mud, seawater, snot — which will often contain dozens or hundreds of different organisms, all unknown, and each with its own DNA. In order to read all the fragmented genetic material, metagenomic sequencing uses sophisticated software to stitch the pieces together by matching overlapping segments.

The assembled genomes are then compared against a vast database of all known genomic sequences — maintained by the government-run National Center for Biotechnology Information — making it possible for researchers to identify everything in the mix

Traditionally, the way that scientists have identified organisms in a sample is to culture them: Isolate a particular bacterium (or virus or parasite or fungus); grow it in a petri dish; and then examine the result under a microscope, or use genomic sequencing, to understand just what it is. But because less than 2 percent of bacteria — and even fewer viruses — can be grown in a lab, the process often reveals only a tiny fraction of what’s actually there. It’s a bit like planting 100 different kinds of seeds that you found in an old jar. One or two of those will germinate and produce a plant, but there’s no way to know what the rest might have grown into.

Such studies have revealed just how vast the microbial world is, and how little we know about it

“The selling point for researchers is: ‘Look, this technology lets you investigate what’s happening in your clinic, whether it’s kids with meningitis or something else,’” DeRisi said. “We’re not telling you what to do with it. But it’s also true that if we have enough people using this, spread out all around the world, then it does become a global network for detecting emerging pandemics

One study found more than 1,000 different kinds of viruses in a tiny amount of human stool; another found a million in a couple of pounds of marine sediment. And most were organisms that nobody had seen before.

After the Biohub opened in 2016, one of DeRisi’s goals was to turn metagenomics from a rarefied technology used by a handful of elite universities into something that researchers around the world could benefit from

metagenomics requires enormous amounts of computing power, putting it out of reach of all but the most well-funded research labs. The tool DeRisi created, IDseq, made it possible for researchers anywhere in the world to process samples through the use of a small, off-the-shelf sequencer, much like the one DeRisi had shown me in his lab, and then upload the results to the cloud for analysis.

he’s the first to make the process so accessible, even in countries where lab supplies and training are scarce. DeRisi and his team tested the chemicals used to prepare DNA for sequencing and determined that using as little as half the recommended amount often worked fine. They also 3-D print some of the labs’ tools and replacement parts, and offer ongoing training and tech support

The metagenomic analysis itself — normally the most expensive part of the process — is provided free.

But DeRisi’s main innovation has been in streamlining and simplifying the extraordinarily complex computational side of metagenomics

IDseq is also fast, capable of doing analyses in hours that would take other systems weeks.

“What IDseq really did was to marry wet-lab work — accumulating samples, processing them, running them through a sequencer — with the bioinformatic analysis,”

“Without that, what happens in a lot of places is that the researcher will be like, ‘OK, I collected the samples!’ But because they can’t analyze them, the samples end up in the freezer. The information just gets stuck there.”

Meningitis itself isn’t a disease, just a description meaning that the tissues around the brain and spinal cord have become inflamed. In the United States, bacterial infections can cause meningitis, as can enteroviruses, mumps and herpes simplex. But a high proportion of cases have, as doctors say, no known etiology: No one knows why the patient’s brain and spinal tissues are swelling.

When Saha and her team ran the mystery meningitis samples through IDseq, though, the result was surprising. Rather than revealing a bacterial cause, as expected, a third of the samples showed signs of the chikungunya virus — specifically, a neuroinvasive strain that was thought to be extremely rare. “At first we thought, It cannot be true!” Saha recalls. “But the moment Joe and I realized it was chikungunya, I went back and looked at the other 200 samples that we had collected around the same time. And we found the virus in some of those samples as well.”

Until recently, chikungunya was a comparatively rare disease, present mostly in parts of Central and East Africa. “Then it just exploded through the Caribbean and Africa and across Southeast Asia into India and Bangladesh,” DeRisi told me. In 2011, there were zero cases of chikungunya reported in Latin America. By 2014, there were a million.

Chikungunya is a mosquito-borne virus, but when DeRisi and Saha looked at the results from IDseq, they also saw something else: a primate tetraparvovirus. Primate tetraparvoviruses are almost unknown in humans, and have been found only in certain regions. Even now, DeRisi is careful to note, it’s not clear what effect the virus has on people. “Maybe it’s dangerous, maybe it isn’t,” DeRisi says. “But I’ll tell you what: It’s now on my radar.

it reveals a landscape of potentially dangerous viruses that we would otherwise never find out about. “What we’ve been missing is that there’s an entire universe of pathogens out there that are causing disease in humans,” Imam notes, “ones that we often don’t even know exist.”

“The plan was, Let’s let researchers around the world propose studies, and we’ll choose 10 of them to start,” DeRisi recalls. “We thought we’d get, like, a couple dozen proposals, and instead we got 350.”

Metagenomic sequencing is especially good at what scientists call “environmental sampling”: identifying, say, every type of bacteria present in the gut microbiome, or in a teaspoon of seawater.

“When you draw blood from someone who has a fever in Ghana, you really don’t know very much about what would normally be in their blood without fever — let alone about other kinds of contaminants in the environment. So how do you interpret the relevance of all the things you’re seeing?”

Such criticisms have led some to say that metagenomics simply isn’t suited to the infrastructure of developing countries. Along with the problem of contamination, many labs struggle to get the chemical reagents needed for sequencing, either because of the cost or because of shipping and customs holdups

we’re less likely to be caught off-guard. “With Ebola, there’s always an issue: Where’s the virus hiding before it breaks out?” DeRisi explains. “But also, once we start sampling people who are hospitalized more widely — meaning not just people in Northern California or Boston, but in Uganda, and Sierra Leone, and Indonesia — the chance of disastrous surprises will go down. We’ll start seeing what’s hidden.”