Today in Science: Hantavirus has a long incubation period

People infected with the Andes strain of the hantavirus may not develop symptoms for up to 42 days ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­

May 13, 2026—People infected with the Andes strain of hantavirus may not show symptoms for more than a month. Plus, researchers spot a galaxy with some of the universe's youngest stars. And make no mistake, chatbots do not think like humans. Let's go. —Andrea Gawrylewski Chief Newsletter Editor HANTAVIRUS UPDATE People exposed to the Andes strain of the hantavirus may not develop symptoms for up to 42 days, a delay that makes tracing infections more difficult. Scroll down for more. | 5 min read Can hantavirus spread through the air? Here's what we do and don’t know. | 4 min read Join the discussion: Do you think the global community is responding well to the hantavirus outbreak? How concerned are you that this will turn into a larger outbreak? Share your thoughts in our online discussion. TODAY'S NEWS Galaxy cluster MACS J0416.1-2403 (MACS0416) magnifies the light from more distant background galaxies through gravitational lensing. NASA/ESA/CSA/STScI/J. Diego/Instituto de Física de Cantabria/J. D’Silva/University of Western Australia/A. Koekemoer/STScI/J. Summers/Arizona State University/R. Windhorst/Arizona State University/H. Yan/University of Missouri Seen just 800 million years after the big bang, an object called LAP1-B is a "cosmic fossil" galaxy that seems to hold some of the first stars to ever shine. | 5 min read Weather radar picks up bird migrations. Here's how scientists determine what's bird and what's weather. | 3 min read Quitting GLP-1s causes weight gain. Scientists are racing to find ways to help people retain their weight loss after they stop taking the medication.​ | 3 min read Probability theory and the Saint Petersburg paradox can help you determine whether to avoid placing a bet because the stakes of a game are too great. | 4 min read The Trinity bomb test left behind strange crystals that scientists have now identified as a new material. | 3 min read Ivermectin prescriptions skyrocketed in the six months after actor Mel Gibson appeared on influencer Joe Rogan’s podcast and claimed a version of the drug successfully treated three of his friends’ cancers, a new study found. | 2 min read A 59,000-year-old Neanderthal tooth shows evidence that it was drilled into. Were they practicing dentistry? | 4 min read Yesterday, Martin “Marty” Makary, one of the most prominent supporters of the Trump administration’s Make America Healthy Again agenda, resigned as Food and Drug Administration commissioner. | 2 min read Are our attention spans really getting shorter because of digital media? Here's what the science says. | 9 min read More News Indulge your love of science with a subscription to Scientific American. Start for just $1 for 90 days. TOP STORIES A Long Incubation Several U.S. passengers onboard the cruise ship at the center of a deadly hantavirus outbreak are back in the country and under medical watch. They will quarantine for 42 days—many of them at a special facility—while they are monitored for signs of infection. Why so long? The Andes virus, the type of hantavirus involved in the outbreak, has a much longer incubation period than other viruses—a range of four to 42 days, with most people showing symptoms around the second to fourth week after exposure. Why this matters: Longer incubation periods can reduce pathogens’ ability to spread quickly from person to person, which typically gives public health officials the upper hand in identifying contacts and monitoring them to control outbreaks. But it can complicate other containment processes. You can fly to the opposite side of the world in a matter of two days, potentially spreading diseases with long incubation periods that you weren't aware you contracted.  How it works: Andes virus quietly circulates in the bloodstream from the initial site of infection. Eventually it infiltrates endothelial cells lining blood vessels throughout the body but primarily in the lungs. The virus replicates there without immediately killing cells and triggering an immune response. Over time, infection and delayed immune activity cause inflammation and fluid to build up in the lungs, making it hard to breathe. One study last year found the virus in blood, as well as in saliva and another fluid in the mouth, even in the final stage of infection. Whether hantavirus spreads through the air or by other means is an open question. Amanda Montañez; Source: Cleveland Clinic, U.S. Centers for Disease Control and Prevention (data) Don't Judge (With AI) In a recent experiment, scientists had humans and AI bots evaluate the credibility of several news sources. While humans evaluated their own knowledge of the facts, the source, and the language they were presented with, AI chatbots' conclusions consistently reflected patterns drawn from language (such as how often a particular combination of words coincided and in what contexts)—it didn’t source references to relevant facts or refer to its own previous experiences.    Why this matters: While AI can reproduce results that look similar to humans’ conclusions, its method of evaluation is still quite different from how humans think. Chatbots generate answers to users’ questions by reproducing existent patterns in language, not by independently evaluating the facts. To the observer, an AI chatbot may sound like it’s evaluating, but they are fundamentally incapable of judgement, says Walter Quattrociocchi, a computer scientist at the Sapienza University of Rome. This is an important distinction for those using chatbots to help them judge difficult situations.    What the experts say: “People are already using these systems in contexts in which it is necessary to distinguish between plausibility and truth, such as law, medicine and psychology. A model can generate a paragraph that sounds like a diagnosis, a legal analysis or a moral argument. But sound is not substance. The simulation is not the thing simulated,” Quattrociocchi says. —Emma Gometz, newsletter editor

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WHAT WE'RE READING One family is behind $65 million in stolen antiquities discovered in art museums around the world. | The Atlantic Alcohol is fueling an unrecognized epidemic in the U.S., an investigation finds. | STAT Struggling gig-workers in Hollywood don't wait tables anymore for cash. They train AI programs. | WIRED What questions do you have about hantavirus? Reply to this email or use the address below to send them to me and I'll publish answers in an upcoming newsletter. Personally, I'm curious about how many other diseases like this are waiting in the wings, and the likelihood of them popping up in the coming years. Which are the infections we most need to be keeping an eye on?  Send questions and other feedback on this newsletter to newsletters@sciam.com. We'll be back tomorrow.    —Andrea Gawrylewski, Chief Newsletter Editor

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