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C. Goldsmith

Happy Virus Appreciation Day!

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C. Goldsmith

According to several of those sites where you can find a holiday for anything, October 3rd is Virus Appreciation Day. Nobody seems to know why this is Virus Appreciation Day, or whose idea is it, or whether they meant computer viruses or the biological cell-invading kind. But hey, it's a holiday, so we will celebrate, well, not viruses, but the success we've had so far in fighting them.

Smallpox virus.

Most viruses are not much to celebrate, but we can celebrate the fact that medical science is fighting them and making a lot of progress. One of the best virus stories is that of smallpox. Smallpox is caused by the Variola virus, and documented human cases go back 3,000 years. Scientists studying viral DNA estimate the disease invaded humans as far back as 10,000 years ago. Smallpox viruses com in two forms, with the more dangerous resulting death to a third of those who contract it. It wasn't a huge problem until people began to settle into crowded cities during the Middle Ages. It then devastated the natives of the Americas, who had no natural immunity, when Europeans arrived in the 1500s.

The value of inoculation was known for hundreds of years, and methods were developed to induce a mild case of smallpox, so the body would develop immunity. It wasn't perfect, and people still died. Dr. Edward Jenner knew that milkmaids who had suffered cowpox were immune to smallpox, so in 1796 he introduced pus from a cowpox-infected milkmaid to the body of eight-year-old James Phipps. Phipps was not the first to be inoculated with cowpox in hopes of smallpox protection, but Phipps was later exposed to smallpox (by Jenner) several time and his immune system fought it off.

An 1802 cartoon makes a joke of cowpox inoculation.

The World Health Organization announced an initiative in 1967 to eradicate smallpox from the entire world. The vaccine, which had been steadily improved since Jenner's day, was sent everywhere to inoculate children and adults. Ten years later, smallpox could not be found in the natural world. Only two research repositories remain, one in Atlanta, the other in Russia.

HIV, in green, attacking a lymphocyte. Image by C. Goldsmith.

The world felt pretty good about vaccines against viruses, but in the 1980s, we got a wakeup call. A new and deadly diseases that was eventually called AIDS (acquired immunodeficiency syndrome) was found to be growing in certain populations in which the virus transferred from person to person. It is caused by Human Immunodeficiency Virus, or HIV. The presence of HIV suppresses the body's immune system (particularly a white cell type known as T-cells), allowing any common infection to become life-threatening.

An HIV infected T-cell. Photograph by Flickr user NIAID.

The virus is transmitted by body fluids in close contact, as in sex, sharing needles among drug addicts, childbirth, and in blood transfusions. In addition, the fact that it was initially most prevalent in the gay community in America stigmatized the disease's victims and politicized the fight against it. The lethality of the disease terrified people, no matter how difficult it is to become infected. In the thirty years since we became aware of AIDS, retroviral therapy has helped those infected with HIV to keep from developing AIDS, and safe sex education has popularized the use of condoms for prevention against contracting the virus. However, there is still no effective vaccine or cure for AIDS.

Common polio virus.

Just last week, I posted a story and said, "And we wondered for so long if viruses served any purpose." It was about the trials of Fritz Anderson, who was diagnosed with a deadly brain tumor that did not respond to surgery or chemotherapy. Then he enrolled in an experiment involving a genetically-engineered polio virus that is deadly to cancer cells and does not invade healthy brain tissue. Anderson's skull was opened and the virus was infused into his exposed brain. Two years later, Anderson's tumor appears as only a shadow in his brain. Perhaps viruses are good for something after all. 

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Medicine
New Technique Can Spot a Heart Attack in the Making Long Before It Happens
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Cardiology experts have developed a noninvasive way of measuring the fat around a person's blood vessels, which could help determine their risk for dangerous cardiac events. The researchers described their technique today in the journal Science Translational Medicine.

Heart attacks are incredibly common, affecting around 750,000 Americans every year. Heart disease is the number one cause of mortality in the U.S., responsible for one out of every four deaths. There are many reasons for this. Among them is the difficulty of identifying at-risk patients before it's too late.

Cardiologists' current method of choice uses a metric called coronary calcification score (CCS) to measure the hardening of a patient's arteries. CCS is a reliable way to predict future heart problems, paper co-author Charalambos Antoniades said in a statement, but it has its limitations.

"When coronary calcification is detected," he said, "it is already too late, as the calcification is not reversible."

And so, rather than measuring calcification, many researchers have begun looking for a way to measure blood vessel inflammation, which is usually a pretty good—and early—predictor of heart disease.

The inflammation itself can be hard to see without entering a patient's body. But recent studies have shown that it rarely travels alone: Blood vessels that are inflamed are also often wrapped in larger fat cells than healthy vessels. 

With this link in mind, Antoniades and his colleagues decided to try measuring the fat cells instead. They reviewed computed tomography scans from 453 patients about to undergo heart surgery, and used these data to create what they call the fat attenuation index (FAI). The higher a patient's FAI, the more inflammation they had, and the more advanced or severe their heart disease. 

The researchers then compared the FAI of 40 additional patients with the results of invasive scans of the inflammation in their hearts. Sure enough, each patient's FAI matched the swelling onscreen.

There are many benefits to using FAI, the authors say. Not only is it noninvasive and accurate, but it can be used in tandem with CCS and other methods for an even more complete picture. The next step will be validating the test's safety and accuracy in clinical trials.

FAI scans "could help direct these new types of treatments to the appropriate subgroups of patients at greatest risk," Antoniades says, "reducing costs and targeting more powerful drugs to the patients who will benefit most."

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Health
Don't Panic About the Plague
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If reports of measles and whooping cough making a reappearance aren't alarming enough, the news that three people in New Mexico have contracted plague this year might have you on edge. But these aren't the only recent cases of plague in the state—the disease appeared in both 2016 and 2015, causing one death—or even in the U.S.

In 2015, a child contracted the plague in Yosemite National Park, and so did a tourist from Georgia; park officials closed a campground where they discovered two dead squirrels infected with the disease. That same year in Colorado, a pitbull infected four humans with pneumonic plague before being put down, and two other Colorado residents died from plague, including a 16-year-old boy.

It all seems very scary, but don't go sealing yourself in protective gear yet. There's less to fear about plague than you may think. While the public is prone to panic that a medieval illness, which wiped out a quarter of Europe in the Middle Ages during the Black Death, has suddenly arisen from obscurity, the truth is: Plague never left.

Though we haven't seen a widespread epidemic of plague since the early 20th century, thanks to advances in sanitation and medicine, and there hasn't been a human-to-human case of transmission in America since 1924, an average of seven new cases are reported every year in the U.S. From 2010 to 2015, there were 3248 cases, including 584 deaths, reported worldwide, according to the World Health Organization.

Yersinia pestis, the flea-borne bacteria that's most often responsible for plague, infects rodents; humans are “incidental hosts,” who can acquire the infection if bitten by an infected flea or rodent. Compared to the 14th century, when the Black Death spread wildly, or the late 19th century, when 10 million people died of the disease after it traveled from Hong Kong to port cities worldwide, most people today live in more sanitary conditions and have less frequent contact with the rodents most likely to carry the infected fleas. Today, 95 percent of plague cases originate in parts of sub-Saharan Africa and Madagascar.

The most common of the three strains of plague is the notorious bubonic plague, which causes painful swollen lymph nodes (also called buboes) and was responsible for Europe's Black Death—so named because internal hemorrhages caused by the infection make the skin appear black. But the pitbull that infected four Colorado residents carried the rarer respiratory strain of pneumonic plague, which is contagious when the infected person coughs up infected particulates. There is also septicemic plague, the most lethal form, which infects the blood, and most often occurs when plague virus has gone undetected and is allowed to spread.

In the U.S., you're generally only at risk of contracting plague in late spring to early fall if you've been in a rural or semi-rural area of the West, especially New Mexico, Arizona, or Colorado, and have had contact with fleas or rodents including ground squirrels, chipmunks, prairie dogs, or rats. And even then, the risk is low.

Only the pneumatic version of plague is contagious from human to human (though untreated bubonic plague can become pneumonic), but you have to be coughed upon, or receive fluid from an infected person upon an open wound or directly into your mouth or nose.

Plague symptoms mimic any flu—fever, chills, headache, difficulty breathing or coughing—but people have been known to cough up blood with the pneumonic variety. If you've been in a rural area, or camping, and come down with these symptoms two to three days later, it's best to go to a hospital.

Now for some good news: While untreated plague is quite deadly, people with plague who are treated with antibiotics within 24 hours of infection have strong recovery rates.

So while it's good to be aware and take precautions, the chances of another plague pandemic remain slim.

This story was originally published in 2015 and has been updated. 

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