Ten years ago, Jonathan Kipnis decided to run an experiment to see how well mice can learn new things. He suspected that the immune system was important to cognition, and so he wanted to compare mice with normal immune systems to mice with deficient ones. Kipnis engineered mice that lacked T cells, a type of white blood cell that fights pathogens. At the time, Kipnis was getting his Ph.D. at the Weizman Institute in Israel, and the lab he was working in didn’t have the equipment necessary for the test. So he shipped off his mice–a group of normal ones and a group lacking T cells–to Ben-Gurion University. There, his colleague Hagit Cohen put the mice through their paces.

Cohen gave the mice a task known as the Morris water maze. She put them in a pool of water, where they started to swim frantically. Just under the surface of the water there was a hidden stand. If the mice could find the stand, they could climb onto it and stop their desperate swimming. Over several rounds, the mice learned where the stand was hidden and swam straight for it.

Continue reading “Lifting Brain Fog” →

If you get rabies and don’t get help in time, you will almost certainly die. While there are a few tantalizing reports of people surviving a case of rabies without medical attention, there are all too many cases of people dying after getting bitten by a rabid animal. The virus sneaks from the bite wound into a nearby nerve and then makes its way through the nervous system. Along the way, it can make people mad and send them into comas before killing them. Officially, over 50,000 people die of rabies each year, but that number is likely a gross underestimate. A lot of rabies cases occur in places where the causes of deaths go unrecorded. In one study in Tanzania, doctors determined that the actual number of deaths from rabies was over 100 times higher than the official count.

Continue reading “To Stop Rabies, Stop Helping It” →

Brandon Klug writes, “I got this tattoo in January 2009 during the first year of my MSc research and it encompasses a lot of my scientific interests. My background is in zoology and I have a fascination with anatomy, specifically anything to do with the musculoskeletal system. When I got the tattoo, I was studying adaptations of reproductive and newborn tree-bats in Canada and very quickly became hooked on these amazing animals. One of the biggest puzzles in bat evolution was the question of whether they echolocated or flew first, and this fossil (Onychonycteris finneyi), the oldest bat fossil (52 million years old) yet discovered, led to the conclusion that bats evolved the ability to fly before they developed echolocation. In general, this tattoo represents my love for anatomy, evolution, and bats in general.”

By pure coincidence, I wrote about Onychonycteris finneyi when it was first unveiled in 2008. Here’s my Loom post.

You can see the rest of the Science Tattoo Emporium here and in Science Ink: Tattoos of the Science Obsessed.

Originally published February 10, 2013. Copyright 2013 Carl Zimmer.

I’ve been blogging a lot recently about dangerous viruses, like the flu and norovirus. But, truth be told, a lot of viruses we harbor don’t make us sick. They may even make us healthy. You’d think they’d be worth getting to know. But they’re mostly a mystery to us.

The collection of viruses that are dwelling inside you right now is known collectively as the virome. You might think these viruses were the sort that infect your cells. Some indeed are. There’s a good chance you harbor papillomaviruses in some of your skin cells, for example. And chances are they won’t cause you any harm. Rather than blasting apart your cells, papillomaviruses merely accelerate the rate at which your cells divide. Since you slough off your skin cells, you’re rid of the viruses soon enough anyway. No harm, no foul. The only trouble these viruses can cause is when they end up accelerating your cells until they spin out of control. They can cause cervical cancer and warts when this happens.

Continue reading “Your Inner Lions: Get to Know Your Virome” →

It’s been a rough flu season this winter in the United States and Europe, but it could be worse. A lot worse. The flu viruses that are making us sick go by names like H1N1 and H3N2, referring to the kinds of proteins that stud their surface. There’s another sort of flu lurking in other parts of the world, like Egypt, India, and Cambodia, known as H5N1. Since 2003, 615 people have come down with H5N1, and, as of Feburary 1, 364 of them had died. In January alone, 5 people in Cambodia were diagnosed with H5N1. Four of them died.

There’s a lot of debate about precisely how bad H5N1 is. It’s possible that a lot of people are getting sick with H5N1 without making it onto the official records. They’re crawling off to bed for a week, recuperating, and then getting on with their lives. So the 59 percent death rate you get from the official numbers (what’s known as the case-fatality rate) may be a serious overestimate. Still, even if the true rate was only half as high, H5N1 would not be a virus you’d want to cross paths with. The most famous flu outbreak of all, the so-called Spanish flu of 1918, is estimated to have killed 50 to 100 million people worldwide. But it infected billions, with a death rate of roughly 2 percent. If H5N1 could somehow take off and become a global pandemic, it would become an unparalleled catastrophe even if its official 59 percent case-fatality rate was chopped down by a factor of ten.

Continue reading “The Future Evolution of Bird Flu” →