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.
If you've ever read much about zoonoses — diseases that pass from animals to humans — then you know that the domestication of livestock played a huge role in introducing many diseases to people. Living in close proximity to the animals we ate provided ample opportunities for those animals' diseases to jump over to us. What's interesting about Mycoplasma mycoides is that it represents a disease of animals that seems to have its origins in domestication, as well.
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.
Goodsell's illustration is an attempt to show all the different parts of the bacterial cell, in the shapes, sizes, locations, and concentrations that those parts take in the real world. If you go to his site, you can see a legend explaining what everything is.
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
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
By popular demand (and the help of intrepid readers Broan and theophrastvs), I present you a video clip of the humanoid robot known as Vomiting Larry.
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.
Carl Zimmer had a great piece up yesterday on norovirus, the virus that researchers are studying with the help of Vomiting Larry. His story has more info on how that virus spreads and will give you a better idea of why Vomiting Larry is so important.
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
Even if you don’t immediately recognize the words “prion” or “Kuru”, the history of these pathologies has seeped into popular culture like a horrifying fairy tale. But it’s true: a tribe in New Guinea ate the dead, not as Hollywood-style savages but to respect the dead. Upon death, you took a part of them into yourself. And that included the brain.
Read the rest
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.
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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