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New Research Shows That Humans Spread Plague Long Before Fleas

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The flea's bad reputation may be somewhat undeserved, according to new research. In the 14th century, the insect played a major role in the spread of bubonic plague, which killed tens of millions of people in Asia, Europe, and Africa. But the results of a new study published in the journal Cell suggest that plague was present in human populations twice as long as previously thought, and that it was initially spread by human-to-human contact.

The bacteria that causes plague,Yersinia pestis, was recently found in human teeth dating from 2800 to 5000 years ago. In studying the DNA, researchers found that while the bacteria could not have led to bubonic plague, specifically, it could have caused pneumonic and septicemic plague, resulting in significant population declines in the 4th and 3rd millennia BCE. "By sequencing the genomes, we find that these ancient plague strains are basal to all known Yersinia pestis," the researchers write. "Our findings suggest that the virulent, flea-borne Y. pestis strain that caused the historic bubonic plague pandemics evolved from a less pathogenic Y. pestis lineage infecting human populations long before recorded evidence of plague outbreaks."

The researchers believe that the older strand of Yersinia pestis could not have caused bubonic plague because six of the seven samples were missing key components found in modern samples. A University of Cambridge press statement explains the significance of the missing ymt gene and a mutation of the pla gene in the ancient samples: 

The ymt gene protects the bacteria from being destroyed by the toxins in flea guts, so that it multiplies, choking the flea’s digestive tract. This causes the starving flea to frantically bite anything it can, and, in doing so, spread the plague. The mutation in the pla gene allows Y. pestis bacteria to spread across different tissues, turning the localized lung infection of pneumonic plague into one of the blood and lymph nodes. 

In other words: Fleas likely had nothing to do with the spread of earlier plagues, because back then, the bacteria hadn't evolved the traits it needed to survive inside fleas' digestive tracts. What's more, thanks to a genetic mutation, modern-day Y. pestis is far more likely to have systemic effects than its prehistoric counterpart. 

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Recall Alert: Swiss Rolls And Bread Sold at Walmart and Food Lion Linked to Salmonella
Evan-Amos, Wikimedia Commons // CC 1.0

New items have been added to the list of foods being recalled due to possible salmonella contamination. According to Fox Carolina, snack cakes and bread products produced by Flowers Foods, Inc. have been pulled from stores in Georgia, North Carolina, and South Carolina.

The baked goods company, based in Georgia, has reason to believe the whey powder it buys from a third-party supplier is tainted with salmonella. The ingredient is added to its Swiss rolls, which are sold under various brands, as well as its Captain John Derst’s Old Fashioned Bread. Popular chains that normally sell Flowers Foods products include Walmart and Food Lion.

The U.S. is in the middle of a salmonella outbreak. In June, Kellogg's recalled Honey Smacks due to contamination and the CDC is still urging consumers to avoid the brand. The cereal has sickened dozens of people since early March. So far, there have been no reported illnesses connected to the potential Flower Foods contamination.

You can find the full list of recalled items below. If you have one of these products in your kitchen, throw it out immediately or return it to the store where you bought it to be reimbursed.

  • Mrs. Freshley's Swiss Rolls
  • H-E-B Swiss Rolls
  • Food Lion Swiss Rolls
  • Baker's Treat Swiss Rolls
  • Market Square Swiss Rolls
  • Great Value Swiss Rolls
  • Captain John Derst's Old Fashioned Bread

[h/t Fox Carolina]

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97 Percent of Us Are Washing Our Hands All Wrong
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Most of us know the importance of washing our hands, but we're still pretty clueless when it comes to washing them the right way. As CNN reports, we fall short of washing our hands effectively 97 percent of the time.

That number comes from a new study conducted by the U.S. Department of Agriculture that looked at 383 participants in a test-kitchen environment. When they were told to wash their hands, the vast majority of subjects walked away from the sink after less than 20 seconds—the minimum hand-washing time recommended by the Center for Disease Control and Prevention. Many of them also failed to dry their hands with a clean towel.

The researchers had participants cooking and handling raw meats. Because they didn't wash their hands properly, volunteers were spreading potentially dangerous germs to spice jars 48 percent of the time, contaminating refrigerator handles 11 percent of the time, and doing the same to salads 5 percent of the time.

People who don't wash their hands the correct way risk spreading harmful microbes to everything they touch, making themselves and those they live with more susceptible to certain infections like gastrointestinal illness and respiratory infections. Luckily, the proper hand-washing protocol isn't that complicated: The biggest change most of us need to make is investing more time.

According to the CDC, you need to rub your hands with soapy water for at least 20 seconds to get rid of harmful bacteria. A helpful trick is to sing "Happy Birthday" twice as you wash—once you're finished, you should have passed the 20-second mark. And if your bathroom or kitchen doesn't have a clean towel to dry your hands with, let them air-dry. 

[h/t CNN]

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