David Goodsell of the Scripps Research Institute made this lovely watercolor illustration of a cell of Mycoplasma mycoides. This bacterium is the cause of a deadly respiratory disease that affects cattle and other cud-chewing animals.
In 2012, scientists found evidence that suggests domesticating livestock — a process that resulted in closer living conditions for the animals and in animals from one herd being moved to other herds they likely wouldn't have otherwise had contact with — helped Mycoplasma mycoides evolve and spread. Today, different species of Mycoplasma mycoides cause a range of diseases that can kill between 10 and 70 percent of the cows they infect.
The populations at lowest risk for developing gestational diabetes — namely, ladies of European decent — come from cultures that eat (and have eaten, for thousands of years) dairy and wheat-heavy diets that would, normally, increase your risk. Meanwhile, writes Carl Zimmer at The Loom, Bangladeshi women, who have one of the highest risks for gestational diabetes, come from a culture that traditionally ate a low-carb, low-sugar diet. What's going on here? The answer might lie in evolution. It's a particularly interesting read given the ongoing pop-culture debate about whether 10,000 years is enough time for humans to adapt to eating certain foods. This data on pregnant ladies would suggest the answer is, at least in some respects, yes. — Maggie
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Given the ongoing outbreak of H7N9 flu in China (and, now, also Taiwan), this is a good time to listen to a fascinating podcast discussion with David Quammen. Quammen recently published a FANTASTIC book, Spillover, about zoonoses — the diseases that humans contract from animals. This includes bird flus like H7N9. It also includes AIDS and a whole host of familiar viruses and bacteria. Bonus: Scary disease girl Maryn McKenna has a cameo in the podcast, discussing the way news media (in China and the US) are covering H7N9 and what you can do to better understand what's happening. — Maggie
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Larry is used to study the way particles of puke become aerosolized, and how those particles spread and help infect other people. That's important, because it explains one of the ways that viruses spread by vomiting manage to end up in everyday things like, say, frozen raspberries. Aerosolized vomit isn't something you can spot. It doesn't clean up easily. And even just a drop of it can pass on plenty of viruses.
Here's a headline for you — Worse than sex parasite: Sex parasite with virus. Yes, trichomonas (a sexually transmitted parasite that you've probably never been tested for), can actually harbor its own diseases. When infected with a virus — dubbed trichomonasvirus — trichomonas becomes even worse. Kill it, and it releases the virus, which causes inflammation and can actually lead to worse side-effects for infected people. (Via Charles Q. Choi)— Maggie
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Even if you don't immediately recognize the words "prion" or "Kuru", the history has seeped into popular culture, like a horrifying fairy tale that just happens to be true. Once, there was a tribe in New Guinea that ate the dead. It wasn't the kind of fakey cannibalism you see in the movies, with hunters rushing out to spear people for sustenance. Instead, it was about respecting your elders. When a member of your family died, you ate them—you took a part of them into yourself. And that included the brain.
But over time, these people found themselves plagued with a terrible illness. Children and perfectly healthy adults, usually women, would suddenly begin to lose control of their limbs. They would jerk and shudder. Within weeks, they wouldn't be able to stand up at all. And then they died. Everybody who had those symptoms died.
Eventually, Western scientists would learn the awful truth. When the people from New Guinea ate their ancestors they were also eating a disease. It attacked their brains—riddling the tissue with holes. The New Guineans, the Fore people, called the disease kuru. In their language it meant "trembling" or "fear".
Today, we know a little bit more about the disease, kuru. We know it's not caused by a virus or a bacterium or a fungus. We know it's related to other brain-damaging diseases, including Creutzfeldt-Jakob disease, which turns healthy adults senile and kills them within a year of the onset of symptoms; scrapie, which affects sheep; and the dreaded bovine spongiform encephalopathy -- mad cow disease.
Tying all these diseases together is a scary little something called a prion. On August 16th, I attended a lecture by Jay Ingram, a Canadian journalist who has written a book about prion diseases, called Fatal Flaws. The lecture taught me a lot about prions, but it also taught me about some of the flaws inherent in trying to live-tweet a lecture as I'm listening to it. When the subject is so scary—and so confusing—even well-intentioned live tweets can go awry.
Yesterday, Xeni told you that the deadly virus Ebola has reemerged in Uganda. The disease has actually been infecting and killing people in the western part of the country for three weeks. We're hearing about it now, in big font, because some sources have reported that the disease has reached Kampala, the country's capital. (Other sources say only that one person infected with Ebola traveled to Kampala, and that there have been no reports of anyone catching the disease in that city.)
The Kampala link is somewhat concerning. Previous Ebola outbreaks have centered on rural areas, villages, and mid-sized towns. With the exception of a handful of highly monitored cases that centered around research labs in the U.S. and Europe, and the case of a medical worker who accidentally brought the virus to Johannesburg, South Africa in 1996, Ebola has not previously found its way into any major global hubs of human life. Kampala may not be on your radar with New York, Tokyo, or London, but air travel and money give it strong ties to the rest of the world and population density gives it a much larger number of potential victims within striking distance.
But here is a key thing about Ebola—it's scary as hell, but it burns itself out pretty fast and it's not that easy to spread. On average, Ebola kills a majority of the people it infects, and it kills them quickly. The time between infection and onset of symptoms ranges from two to 21 days. That means the virus only has so long to find new hosts. Meanwhile, Ebola isn't airborne. To catch it, you have to have contact with infected blood or bodily fluids. Historically, it's been a disease of people and their medical workers, or people and their immediate families. In rural communities, Ebola can burn through the small, isolated population and find itself with nowhere to go in the span of a couple months.
Having listened to Radiolab describe the origins and early history of HIV yesterday, I found this press release particularly fascinating. The World Health Organization is investigating an outbreak of an unknown disease in Cambodia. The disease begins with a fever, then progresses into neurological symptoms and very quickly to respiratory failure. All the recorded cases have been in children. 62 children were admitted to hospitals with these symptoms. 61 have died. (I should note that this doesn't necessarily mean that whatever this is has a 98% kill rate. We're only talking about the people whose symptoms were severe enough that they ended up in a hospital. There could be many more asymptomatic or mild cases.) (Via John Rennie) — Maggie
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