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Masum Ibn Musa via Wikimedia Commons // CC BY-SA 4.0

The Devious Strategy of the Mind-Controlling Cat-Poop Parasite

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Masum Ibn Musa via Wikimedia Commons // CC BY-SA 4.0

Toxoplasma gondii, a parasitic protozoan, infects more than 50 percent of people on Earth and millions of cats and other animals, yet the secrets to its success have largely remained a mystery—until now. A new study published in the journal Structure concludes that the parasite can hack into and rewire its host’s immune system to suit its own purposes.

You may not recognize this parasite by name, but you’ve probably heard it mentioned. T. gondii infection, better known as toxoplasmosis, has the power to produce strange changes in its hosts. The parasite can only reproduce within a cat’s body, and scientists believe that it can manipulate other animals to make that happen. Mice with toxoplasmosis lose their healthy fear of cats and will stroll right up to their predators, essentially delivering their parasitic passengers directly into the mouth of the beast.

Some scientists believe that toxoplasmosis can also influence human behavior, and studies have linked infection to symptoms of schizophrenia, bipolar disorder, and intermittent explosive disorder. Other researchers say these findings are overhyped, overblown, and impossible to reproduce.

Whether or not T. gondii can change our minds, it’s definitely changing our bodies. Toxoplasmosis can be dangerous for pregnant women and people with compromised immune systems, but most people never even know they’re sick—which is not how our bodies are supposed to work. Our immune systems are supposed to protect us from parasites like T. gondii, or, if they can’t, at least alert us by getting riled up and inflamed.

But somehow, this intruder found a way to override our personal security systems. The first clue to its strategy came last year, when scientists at the Institute for Advanced Biosciences discovered that T. gondii makes a protein called GRA24 that in turn convinces the body to make an inflammatory protein called p38α.

This raised a new question, one which became the focus of the new study: Why would a parasite ever want to trigger inflammation?

The researchers cultured human cells in the laboratory, then gave them toxoplasmosis and monitored the molecular-level interactions between the two proteins. They discovered that GRA24 can essentially hot-wire the security system and bypass multiple steps of the immune response process. By making its own p38α, T. gondii can control the flow and extent of inflammation. It doesn’t shut down the immune system; doing so could make its host sick and jeopardize the parasite’s new, cushy existence. Instead, it muffles the system just enough to keep itself safe and undetectable.

Watch your back, T. gondii. We're on to you.

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CDC Traces Infectious Disease Outbreak in Seven States to Pet-Store Puppies
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Campylobacter bacteria have infected 39 people in seven states, and puppies sold at one chain of pet stores in Ohio are likely to blame. As NPR reports, a federal investigation is currently underway as to the exact cause of the outbreak of the intestinal infection.

The symptoms of Campylobacter include fever, diarrhea, and abdominal pain, and in rare cases it can lead to death in victims with weakened immune systems. About 1.3 million people fall ill to it each year, but the bacteria can also infect animals like dogs.

Of those hit by the latest outbreak, 12 are employees of the national chain Petland in four states, according to the CDC. The other 27 have either bought a puppy from a Petland store recently or live with or visited someone who has. Eighteen cases have been reported in Ohio, and the rest have appeared in Florida, Kansas, Missouri, Pennsylvania, Tennessee, and Wisconsin. While no deaths have been reported, nine victims have been hospitalized.

Puppies, like humans babies, are more likely to get sick than full-grown dogs, which may explain how the Petland animals caught the illness in the first place. But even apparently healthy adult dogs may be harboring the bacteria and spreading it through their feces. To avoid catching it from your canine companion at home, the CDC recommends washing your hands whenever you make physical contact. This also applies when handling their food and especially when picking up and throwing away their poop (with disposable gloves of course).

For the small percentage of people who do contract the infection each year, the best course of action is to wait it out if you're healthy otherwise: Symptoms take about a week to clear up.

[h/t NPR]

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10 Intriguing Facts About Joseph Lister
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Surgical patients once routinely died from their operations, as physicians believed that bad air—not bacteria—was responsible for their post-operative infections. This changed in the 19th century with a British physician named Joseph Lister (1827-1912), who dedicated his life to learning what caused infections and how to prevent them.

Get to know the quiet, studious doctor who is often called “the father of modern surgery"—and who has both a mountain and a popular mouthwash brand named after him.

1. JOSEPH LISTER'S FATHER HELPED USHER IN THE MODERN MICROSCOPE—AND HIS SON'S FUTURE CAREER.

As a child, Lister’s scientific curiosity was encouraged by his father, Joseph Jackson Lister, who was an English wine merchant and amateur scientist. The elder Lister's tinkering with early microscopes paved the way for today’s modern achromatic (non-color distorting) microscope—an accomplishment that would admit him to the Royal Society, the world’s oldest national scientific society.

In addition to dissecting small creatures, articulating their skeletons, and sketching the remains, the younger Lister—who knew from an early age that he wanted to be a surgeon—spent much of his childhood using his father's microscopes to examine specimens. He would rely on microscopes throughout his scientific career, using them to research the action of muscles in the skin and the eye, how blood coagulated, and how blood vessels reacted during an infection’s early stages.

2. LISTER WAS ENGLISH, BUT HE SPENT MOST OF HIS CAREER IN SCOTLAND.

Lister was born in the village of Upton, in Essex, England, and studied at University College, London. After graduating and working as a house surgeon at University College Hospital—where he became a Fellow of the Royal College of Surgeons—the young doctor moved to Edinburgh, Scotland, to work as renowned surgeon James Syme's assistant at the Royal Infirmary [PDF].

The move was supposed to be temporary, but Lister ended up finding both professional and personal success in Scotland: He married Syme’s daughter, Agnes, and was eventually appointed Regius Professor of Surgery at the University of Glasgow.

3. HE THOUGHT ABOUT BECOMING A PRIEST INSTEAD OF A DOCTOR.

Like many young professionals, Lister sometimes had doubts about his career path. The physician received a devout Quaker upbringing, and at one point he considered becoming a priest instead of a surgeon. However, Lister’s father encouraged him to stay in medicine and serve God by helping the sick. Lister would ultimately leave the Quaker faith to marry Agnes Syme, who belonged to the Scottish Episcopal Church.

4. HE STRUGGLED WITH DEPRESSION.

While away at school, Lister came down with a mild case of smallpox. He recovered, but the health scare—along with the death of his older brother, who succumbed to a brain tumor—pushed him into a deep depression. The student left school in London and traveled around Britain and Europe for a year or so before returning to the university and pursuing his medical studies with renewed vigor.

5. LISTER IS THE REASON WE STERILIZE WOUNDS.

When Lister was a surgeon, bloodstained bed linens and lab coats weren’t washed, and surgical instruments were rarely cleaned. And even though Italian physician Fracastoro of Verona had theorized in 1546 that small germs could cause contagious diseases, nobody thought they had anything to do with wound infections. Instead, many surgeons believed that miasmas—or bad air—emanating from the wound itself were responsible.

Lister, however, trusted his own observations. As a young doctor-in-training, he noted that some wounds healed when they were cleaned and damaged tissue was removed. However, the problem of infection continued to plague Lister through his career until he encountered the work of French scientist Louis Pasteur, who discovered that microbes could cause infection.

Intrigued, Lister began using a formula of diluted carbolic acid—a coal-tar derivative used to kill parasites found in sewage—to sterilize medical instruments and wash his hands. He also applied this mixture to bandages, and sprayed carbolic acid in operating rooms where surgeries resulted in high mortality. He reported the results at a meeting of the British Medical Association in 1867: "my wards […] have completely changed their character, so that during the last nine months not a single instance of [blood poisoning], hospital gangrene, or erysipelas has occurred in them.”

While some physicians balked at his techniques, claiming they wasted time and money, Lister’s approach caught on. Soon, physicians in Germany, the U.S., France, and Britain were following his lead. As for Pasteur and Lister, the two scientists corresponded, and would finally meet in person for the first time in 1878. And at Pasteur's 70th birthday celebration in 1892, Lister gave a praise-filled speech about the life-saving benefits of Pasteur's research.

6. LISTER WAS KIND TO PATIENTS.

Lister referred to some patients as "this poor man" or "this good woman" (he refused to call them "cases"), and he always tried to keep them calm and comfortable pre-and post-operation. Once, the surgeon even sewed a doll's missing leg back into place for a young charge.

7. HE TREATED QUEEN VICTORIA ...

Lister's most famous patient was Queen Victoria: In 1871, the surgeon was called to the monarch's estate in the Scottish Highlands after the queen sprouted an orange-sized abscess in her armpit. Armed with carbolic acid, Lister lanced the mass, drained its pus, and dressed and treated the wound to prevent infection—but at one point, he accidentally sprayed his disinfectant in the displeased queen's face.

Lister would later joke to his medical students, "Gentlemen, I am the only man who has ever stuck a knife into the queen!"

8. ... WHO LATER MADE HIM A BARON.

As Lister's fame grew, Queen Victoria made him a baronet in 1883. Later, she elevated the physician to baron status. Lister would remain beloved among members of the royal family, including Edward VII, who was diagnosed with appendicitis two days before his royal coronation in 1902. His doctors consulted Lister before performing a successful surgery, and the king made sure to thank him once he was crowned. "I know that if it had not been for you and your work, I wouldn’t be sitting here today," the monarch told Lister.

9. LISTERINE MOUTHWASH IS—SURPRISE!—NAMED AFTER LISTER.

Even if you didn’t learn about Lister in science class, you’ve probably used his namesake formula: Listerine. The popular mouthwash brand—which is promoted with the slogan "Kills germs that cause bad breath"—was originally invented in 1879 by American physician Joseph Lawrence. Lawrence had created the green liquid as an alcohol-based surgical antiseptic, and he fittingly named the product after his pioneering predecessor. However, Listerine would ultimately be marketed for oral hygiene purposes, after first being peddled as a cigarette additive, a cure for the common cold, a dandruff treatment, and more.

10. LISTER ALSO HAS A MOUNTAIN NAMED AFTER HIM.

Lister has public monuments and hospitals dedicated to him around the world, but if you travel to Antarctica, you may also encounter a massive mountain named in his honor: At around 13,200 feet, Mount Lister is the highest point in the Royal Society Range, a mountain range in Victoria Land, Antarctica, that was first explored by the British during the Discovery Expedition from 1901 to 1904. This expedition was organized by the Royal Society and the Royal Geographical Society—and since Lister was the Royal Society’s president from 1895 to 1900, the range’s most majestic peak was named after him.

Additional Source: The Butchering Art: Joseph Lister's Quest to Transform the Grisly World of Victorian Medicine by Lindsey Fitzharris

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