New Study May Explain How Zika Virus Causes Microcephaly

Dr. Stella Guerra performs physical therapy on an infant born with microcephaly at Altino Ventura Foundation on June 2, 2016 in Recife, Brazil. Image Credit: Mario Tama // Getty Images

 
One question underlies the race for a Zika vaccine: What is this virus, exactly, and how does it work? A new paper in the journal Cell Host & Microbe takes us one step closer to understanding by illuminating the relationship between Zika infection and microcephaly.

Babies with the congenital condition called microcephaly are born with unusually small heads and often have difficulties with brain development. Women who become infected with Zika virus while pregnant are at risk for transmitting the virus to their infants, who may be at higher risk for microcephaly. But just how Zika causes microcephaly has remained something of a puzzle.

To take a closer look, researchers at Stanford University cultured human stem cells in petri dishes and infected them with the virus. As the cells developed into embryos, the team was able to monitor exactly what went wrong with which cells.

Previous studies had focused on neural progenitor cells, which eventually grow into the nervous system. The Stanford team found a vital element in a second type of cell: cranial neural crest cells (CNCC). But where neural progenitor cells are easily killed off by the virus, cranial neural crest cells responded quite differently, secreting two kinds of cytokines, or inflammatory immune response signaling molecules, in reaction to the presence of the virus. That triggered the growth of more new neural cells—and sent the process of brain and skull development off the rails. Some cells split prematurely, and others died. The virus effectively interfered by confusing communication—or "crosstalk," as the researchers describe it—between cranial neural crest cells and neural progenitor cells.

"Our results suggest that CNCC infection by ZIKV may contribute to associated embryopathies through signaling crosstalk between developing face and brain structures," they write.

Co-senior author Joanna Wysocka is a chemical and systems biologist at the Stanford University School of Medicine. She says it’s possible that the virus is affecting still other cell types in addition to these two.

“Neural crest cells are one example,” she said in a press statement, “but such mechanisms may also be relevant to other tissues that come in contact with the developing brain during head formation and could be infected by Zika virus.”

Wysocka emphasized that microcephaly is a congenital issue and not a risk for adults who contract the virus.

The team’s findings are “remarkable,” physician Larry Brilliant tells mental_floss. (Brilliant was unaffiliated with the study.) The notion of crosstalk between the cell types is “phenomenally important,” he said, because “they lead to questions of [whether] therapeutic interventions might be possible even after the virus is transmitted.”

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Health
Canine Flu is On the Rise: Here's What You Should Know
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It's been eight years since the World Health Organization announced the end of the swine flu pandemic, and now the condition is back in the news for infecting a different type of host. As Live Science reports, the H1N1 virus is mixing with canine flu to create new strains that could potentially spread to people.

Dog flu has been around for a couple of decades, but the two main canine strains, H3N8 and H3N2, have never been contracted by humans. According to a new study published in mBio, some dogs in the Guangxi region of China were found carrying H1N1, the flu strain at the root of the swine flu outbreak. Researchers also discovered three entirely new flu strains that were a combination of H1N1 and regular dog flu viruses.

The unrecognized flu strains are the most troubling discovery. As the flu travels between species, it mingles with viruses that are already there, creating a level of genetic diversity that leaves our immune systems, which are best equipped to fight strains they've already been exposed to, vulnerable. The swine flu epidemic of 2009 started in a similar way, when H1N1 jumped from birds to pigs, and eventually to people.

But the new report isn't a reason to banish your pet to the doghouse next time she seems under the weather. The virus samples were collected from dogs in China between 2013 and 2015, and in the years since, zero humans have caught influenza from dogs (though dog flu has started spreading to cats). If the virus continues mutating to the point where it can infect humans, both the CDC and U.S. Department of Agriculture will take action. But for now, the CDC states that canine flu viruses "pose a low threat to people."

Canine flu may not be dangerous to humans yet, but it can still be stressful for dog owners if their pet comes down with a case. Ask your vet about getting your dog vaccinated, and if you see your dog coughing, sneezing, and acting less energetic than usual, make an appointment to get him checked out as soon as possible. If he does have the flu, he can be treated with plenty of rest and hydration.

[h/t Live Science]

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3 Simple Ways to Stay Tick-Free This Summer
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As the weather gets warmer, you no doubt want to don your favorite shorts and get out in the sunshine. Unfortunately, shorts season coincides with tick season, and we're in the midst of what one expert calls a "tick explosion."

Tick expert Thomas Mather of the University of Rhode Island told Boston 25 News that warm weather is going to lead to a particularly bad summer for ticks. The blood-sucking bugs aren't just annoying—they spread Lyme disease and several other serious illnesses, including a pathogen that can cause a sudden allergy to meat.

There are several precautions you should take to stay safe from ticks and the risks they carry during the high season, which usually lasts from April to September, though some ticks can stay active year-round as long as it's above freezing. While ticks usually live in grassy or wooded areas, you should be careful even if you live in the city, because pathogen-spreading ticks can still be hiding in urban parks.

Tick prevention begins when you get dressed. Wear long sleeves and pants, and if you're in a tick-prone area, tuck your pants into your socks to better protect your legs. Opt for light colored clothing, because it's easier to see bugs against a light color versus a dark one.

You'll want to invest in insect repellent, too, for both you and your pets. The CDC recommends treating your clothing (and tents, and any outdoor gear) with permethrin, an insecticide that you can apply to fabric that will last through several washes. Permethrin not only repels ticks, but kills them if they do manage to get onto your clothes, and you can buy socks and other clothing that come pre-treated with it. Insect repellents with DEET are also effective against ticks.

Since ticks are most likely to make their way onto your feet and ankles, make sure to treat your shoes and socks. And since your dog is more likely to get a tick than you are, make sure to get Fido a tick collar or some other kind of tick medication.

Most of all, you just need to stay vigilant. When you come inside from the outdoors, check your body for any ticks that may have latched on. Ticks can be as small as a poppyseed, so make sure to look closely, or ask someone else to check hard-to-see places like your back. And since they like moist areas, don’t forget to give your armpits and groin a careful look. If you do catch a tick, remove it as soon as you can with a pair of tweezers.

Best of luck out there.

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