Even New Birth Control Pills May Raise Women’s Breast Cancer Risk

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Even New Birth Control Pills May Raise Women’s Breast Cancer Risk

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Even New Birth Control Pills May Raise Women's Breast Cancer Risk

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Using hormonal birth control methods — including newer types of birth control pills, as well as intrauterine devices (IUDs) and implants — may slightly increase women’s risk of breast cancer, according to a new study from Denmark.

The study builds on earlier findings linking hormonal birth control and breast cancer, but the new study focused on newer forms of birth control.

The study, which included about 1.8 million women in Denmark, found that those who used hormonal birth control methods were 20 percent more likely to develop breast cancer over an 11-year period, compared with those who never used hormonal birth control.

Still, a woman’s overall chance of developing breast cancer linked to hormonal birth control use was quite small: The researchers estimate that there would be 1 extra case of breast cancer for every 7,690 women who took hormonal contraception (or 13 extra cases of breast cancer for every 100,000 women who used hormonal contraception). [10 Do’s and Don’ts to Reduce Your Risk of Cancer]

When the researchers examined a number of different hormonal formulations used in birth control, they found that all of the formulations raised the risk of breast cancer by about the same amount. (Hormonal birth control methods typically use either a combination of the hormonesestrogen and progestin, or progestin by itself.)

The study is published today (Dec. 6) in The New England Journal of Medicine.

Not a “new” link

The findings of alink between hormonal contraception and breast cancer is not new; studies going back decades have suggested that the hormones in birth control could raise the risk of breast cancer. But these earlier studies looked mainly at older types of birth control pills, which had a higher dose of estrogen than today’s pills. Therefore, it wasn’t clear if this risk applied to newer formulations of birth control pills or to other birth control methods, including intrauterine devices (IUDs) and implants that contain only the hormone progestin.

The new study “confirms that the increased breast cancer risk … that was initially reported with the use of older, often higher-dose formulations also applies to contemporary formulations” of birth control, David Hunter, a professor of epidemiology and medicine at Oxford University’s Nuffield Department of Population Health in the United Kingdom, wrote in an editorial that accompanied the study. “These results do not suggest that any particular preparation is free of risk,” Hunter added.

But this risk should be weighed against the important benefits of hormonal contraception, which is an effective method of birth control, the researchers, from the University of Copenhagen, wrote in their study. What’s more, other studies have found that taking hormonal birth control may actually reduce the risk of other cancers, including ovarian cancer, endometrial cancer and colorectal cancer, they said.

Risk with longer use

The new study involved women in Denmark ages 15 to 49 who had not previously been diagnosed with cancer. The researchers used nationwide registries to collect information about prescriptions that were filled for hormonal contraception, as well as diagnoses of breast cancer.

The longer women used hormonal contraception, the greater their risk of breast cancer, the researchers found. Using hormonal contraception for less than one year did not increase women’s risk of breast cancer. However, using hormonal contraception for 10 years was linked with a 40 percent increase in the risk of breast cancer, compared with those who had never used hormonal contraception.

Once women stopped using these forms of birth control, the increased risk of breast cancer disappeared if the women had used hormonal contraception for less than five years. But if they had taken hormonal contraception for more than five years, the higher risk of breast cancer persisted for at least five years after their discontinuation of hormonal birth control, the study found. [Beyond Birth Control: 5 Conditions ‘The Pill’ Can Help Treat]

The findings held even after the researchers took into account some factors that can affect the risk of breast cancer, such as becoming pregnant or having a family history of the disease.

But the study did not account for some other things that affect breast cancer risk, including physical activity levels and alcohol consumption.

Still, the researchers noted that any unaccounted factors would need to have a large effect on the risk of breast cancer and be very common in the population to explain the results.

The study was funded by the Novo Nordisk Foundation, a commercial foundation in Denmark that funds research to support its business interests, which include the pharmaceutical company Novo Nordisk. It had no role in the design, analysis or interpretation of the study, or in writing the paper.

Original article on Live Science.


Don’t Blink: Striking Image Shows Bullet in Man’s Eye Socket

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Don’t Blink: Striking Image Shows Bullet in Man’s Eye Socket

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Don't Blink: Striking Image Shows Bullet in Man's Eye Socket

This CT scan shows a bullet that came to rest in a man’s eye socket.

Credit: Reproduced with permission from JAMA Ophthalmology. 2017. doi: 10.1001/jamaophthalmol.2017.40502017. Copyright© 2017 American Medical Association. All rights reserved.

A striking new image shows a bullet lodged in a man’s eye socket.

The 45-year-old man went to the emergency room after he was shot with a 0.22 caliber pistol, according to a new report of the case, published today (Nov. 30) in the journal JAMA Ophthalmology. The bullet went through a wooden door before entering the man’s right eye.

The bullet came to rest in the man’s eye socket, right up against a muscle that controls eye movement. It did not fracture his skull, the report said.

The man was in severe pain, and doctors could see an entry wound for the bullet in the corner of the man’s eye. There was damage to ducts in the eyelid through which tears drain. [‘Eye’ Can’t Look: 9 Eyeball Injuries That Will Make You Squirm]

The man had surgery to remove the bullet and repair the damage to the tear ducts. Afterwards, the man’s pain improved rapidly, and his vision wasn’t affected by the bullet, the report said.

If a bullet enters the eye socket, it often results in significant destruction of the socket, sinuses and brain, the report’s authors noted. But in this case, the man experienced only limited damage to his eye socket because the bullet passed through a door first, which slowed it down, they said.

Original article on Live Science.

Sleep Apnea: Symptoms, Causes and Treatments

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Sleep Apnea: Symptoms, Causes and Treatments

Taking a nap in the afternoon is common in many societies.

Credit: © Marcin Kempski |Dreamstime.com”

Sleep apnea is a condition in which people experience pauses in breathing or shallow breathing during sleep. According to the American Sleep Apnea Association, around 22 million Americans may suffer from sleep apnea and around 80 percent of moderate and severe obstructive sleep apnea goes undiagnosed.

These pauses in breathing, called apneas, can occur as often as 30 or more times per hour, according to the National Heart, Lung and Blood Institute. Sleep apnea may result in poor sleep and lead to daytime sleepiness. Between 12 and 18 million U.S. adults have sleep apnea, the NHLBI says.

There are two main types of sleep apnea: obstructive sleep apnea and central sleep apnea.

In obstructive sleep apnea, the airway becomes partially or fully blocked during sleep. This may happen because the muscles of the throat and tongue relax more than they should during sleep, which hinders air flow to the lungs, the NHLBI says. Other factors that can lead to a blocked airway during sleep include having tonsils that are large compared with the opening of the windpipe, and being overweight, which can narrow the inside of the windpipe.

A blocked airway can lead to a drop in blood oxygen levels, which triggers the brain to arouse you from sleep, so that your airway re-opens, the NHLBI says. This awakening may be so short that you do not remember it,according to the Mayo Clinic. When normal breathing resumes, there is often a loud snort or choking sound.

Central sleep apnea is less common than obstructive sleep apnea. With central sleep apnea, the brain stops sending signs to the muscles that allow you to breath. The condition may be due to other medical problems, such as problems that affect the brain stem, Parkinson’s disease, obesity and heart failure, according to the National Institutes of Health.

Some people have a combination of obstructive and central sleep apnea, known as mixed sleep apnea.

The most common symptom of obstructive sleep apnea is loud snoring, although not everyone who snores has sleep apnea, according to NHLBI. People with the condition may also have pauses in snoring, followed by choking or gasping. Daytime sleepiness is also another common sign of sleep apnea.

Other signs of sleep apnea include:

  • Headaches in the morning
  • Waking up with a dry mouth or sore throat
  • Difficulty learning or concentrating during the day
  • Waking up frequently in the night to urinate
  • For central sleep apnea, waking up suddenly with shortness of breath

Because these breathing problems happen during sleep, people are often not aware that they have sleep apnea, and a family member or significant other is often the first person to spot the problem.

“A lot of times [patients] are brought in by their spouse,” said Dr. Robert Lapidus, an associate professor in the Divisions of Pulmonary, Critical Care and Sleep Medicine at National Jewish Health Hospital in Denver.

Sleep researchers classify sleep apnea as mild, moderate or severe based on the number of apneas and hypopneas that a patient experiences per hour during sleep. An apnea is a cessation of airflow that lasts at least 10 seconds, and a hypopnea is a reduction in airflow of at least 30 percent that’s associated with a drop in blood oxygen levels, and lasts at least 10 seconds, Lapidus said.

Less than five of these events per hour is considered normal, five to 15 is considered mild sleep apnea, 15 to 30 is considered moderate sleep apnea, and greater than 30 is considered severe sleep apnea, Lapidus said.

Though feeling sleepy may also be a symptom, women perceive sleep differently than men, said Dr. Stuart Quan, a sleep medicine specialist and researcher at Brigham and Women’s Hospital in Boston. So, this symptom may be confusing. Men may say they are “feeling sleepy,” which to them means they could fall asleep right now if they went to bed, but women are more likely to say they “feel tired or fatigued,” he said. “Tired can mean a lot more than sleepy,” Quan noted. It might not necessarily mean that the person could lie down and fall asleep. [Missing Zzzs: Sleep Problems Common for Single Parents, Women]

People are at increased risk for obstructive sleep apnea if they are overweight/obese, are older than 60, or are male — men are twice as likely as women to have sleep apnea, according to the Mayo Clinic.

However, women, and people who are thin, can still develop sleep apnea. People who have small airways, or enlarged tonsils, may be at increased risk for the condition. You may also be more likely to develop sleep apnea if you have family members with the condition.

A sleep apnea diagnosis is based on a medical history, a physical exam — which looks at the tissue in your mouth, nose and throat — and a sleep test.

Sleep tests are the most accurate way of diagnosing sleep apnea, NHLBI says. One type of sleep test is a polysomnogram. For this test, individuals stay overnight in a sleep lab and have sensors attached to their body to monitor brain activity, eye movements, heart rate and blood pressure.

There are also home-based tests for sleep apnea, which involve using a portable monitor to record oxygen levels in the blood, heart rate and breathing patterns.

An increasing number of sleep apnea patients are being diagnosed with home-based tests, Lapidus said. Home tests are much less expensive than lab tests, more convenient to the patient, and generally provide comparable information to lab tests if patients do not have comorbidities like heart disease, Lapidus said.

However, if a patient does have comorbidities (another condition such as Parkinson’s or anxiety, for example), then doctors like to perform a lab-based test, Lapidus said. In addition, home-based tests may underestimate the severity of the sleep apnea, so if a home-base tests shows a normal result, but doctors are concerned about sleep apnea, a patient may need to repeat the test is a lab, Lapidus said.

People with mild sleep apnea may only need to make some lifestyle changes to improve their condition, such as weight loss, smoking cessation and sleeping on their side instead of their back, according to NHLBI.

A mouthpiece designed to keep the airway open may also help people with mild sleep apnea. These are available from a dentist. Some of these mouthpieces work by bringing the jaw forward. However, these appliances are not as reliably effective as other treatments for sleep apnea, according to the Mayo Clinic.

The most common treatment for moderate to severe sleep apnea is continuous positive airway pressure (CPAP). The device involves a mask over the nose, or mouth and nose, that uses air pressure to keep the throat open during sleep.

If a patient has a lab-based test for sleep apnea, then a technician may also be able to determine the optimal level of air pressure that the patient needs, Lapidus said.

If patients have a home test that shows they have sleep apnea, they can undergo a second home test to determine their treatment, using a device that automatically adjusts the air pressure up and down, Lapidus said.

Some patients will stop using their CPAP machine because they think the device is uncomfortable, but a lot of things can be done to improve the comfort of the device, Lapidus said. These include a fitting so that the mask fits more comfortably, padding devices that reduce pressure on the skin, and a machine that gradually increases air pressure, so that a patient can fall asleep with a lower air pressure, Lapidus said.

In some cases of sleep apnea, surgery is performed to widen the breathing passages. This is generally done only if other treatments have failed, according to the Mayo Clinic.

Amber Angelle and Alina Bradford contributed to this article.

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Outbreak in Uganda: What Is the Marburg Virus?

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Outbreak in Uganda: What Is the Marburg Virus?

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Outbreak in Uganda: What Is the Marburg Virus?

Credit: CDC/ Frederick Murphy

Three people in Uganda and Kenya have died from an extremely rare and deadly disease caused by the Marburg virus, the World Health Organization reported today (Nov. 7).

The Marburg virus is related to another notorious virus, the Ebola virus, according to WHO. Both viruses are members of the “filovirus” family and have high fatality rates. The fatality rate for the disease caused by the Marburg virus can be as high as 88 percent.

The Marburg virus is transmitted to people from a type of fruit bat calledRousettus aegyptiacus, or the Egyptian fruit bat, WHO says. Once a human is infected, however, the virus can be spread to other humans via direct contact with bodily fluids, or by coming into contact with surfaces and materials that have been contaminated with these fluids. [The 9 Deadliest Viruses on Earth]

The amount of time it takes for symptoms to appear after a person is infected with the virus — known as the incubation period — can vary from two to 21 days, WHO says. But when symptoms begin, they begin abruptly, and can include muscle aches and pain. About three days after symptoms begin, a person can develop gastrointestinal symptoms, including nausea, vomiting and severe diarrhea that can persist for a week. WHO describes patients at this phase of the infection as “ghost-like,” with drawn features, deep-set eyes, expressionless faces and extreme lethargy.

Like the Ebola virus, the Marburg virus causes a condition called severe hemorrhagic fever, which includes symptoms such as a high fever and dysfunction in the body’s blood vessels, which can result in profuse bleeding. These hemorrhagic symptoms often begin between five and seven days after the onset of symptoms, according to WHO. Blood may be found in vomit and feces, and patients may also bleed from the nose, gums and, for women, the vagina. Bleeding at injection sites during medical treatment can be “particularly troublesome,” according to WHO.

The virus can also cause problems with the central nervous system, leading to confusion, irritability and aggression, WHO says.

In fatal cases, death occurs between eight and nine days after the symptoms begin, usually due to severe blood loss and shock, according to WHO.

In the current outbreak, which was declared on Oct. 19, the three people who died came from the same family in the Kween District in Eastern Uganda, according to WHO. One of the individuals traveled to Kenya prior to his death. Because only three people have been infected thus far, and all three died, the current outbreak has a fatality rate of 100 percent.

Originally published on Live Science.

Here’s What Happens in the Brain When You Don’t Get Enough Sleep

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Here’s What Happens in the Brain When You Don’t Get Enough Sleep

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After a sleepless night, you likely feel sluggish the next morning, and a small new study suggests why: Your brain cells feel sluggish, too. And when those brain cells are tired, you may be more likely to be forgetful and get distracted more easily, the research found.

In the study, the researchers found that sleep deprivation makes it difficult for brain cells to communicate effectively, which, in turn, can lead to temporary mental lapses that affect memory and visual perception.

In other words, the findings offer clues as to why a sleepless night makes it so hard to think and concentrate the next day. [The Spooky Effects of Sleep Deprivation]

“We discovered that starving the body of sleep also robs neurons of the ability to function properly,” senior study author Dr. Itzhak Fried, a professor of neurosurgery at the University of California, Los Angeles (UCLA), said in a statement. “This paves the way for cognitive lapses in how we perceive and react to the world around us.”

To study the effects of sleep deprivation, the researchers recruited 12 patients with epilepsy who, as part of a preparation for surgery unrelated to the study, had electrodes implanted into their brains.These electrodes allowed the researchers to monitor hundreds of individual brain cells.

The people in the study then had to stay up for an entire night. During this time, the researchers measured the participants’ brain activity as they carried out certain tasks. For example, the patients were asked to categorize various imagesof faces, places and animalsas fast as possible. Each image caused cells in areas of the brain to produce distinctive patterns of electrical activity. Specifically, the researchers focused on cell activity in the temporal lobe, which regulates visual perception and memory.

The researchers found that as the patients got tired, it became more challenging for them to categorize the images, and their brain cells began to slow down.

“We were fascinated to observe how sleep deprivation dampened brain cell activity,” lead study author Yuval Nir, a sleep researcher at Tel Aviv University in Israel, said in the statement. “Unlike the usual rapid reaction, the neurons responded slowly, fired more weakly and their transmissions dragged on longer than usual.”

In addition, the researchers found that sleep deprivation affects some areas of the brain more than others. Regions of the brain that experienced sluggish brain cell activity also exhibited brain activity normally seen whena person is asleep, the researchers said.

“This phenomenon suggests that select regions of the patients’ brains were dozing, causing mental lapses, while the rest of the brain was awake and running as usual,” Fried said.

In addition, the findings suggest that a lack of sleep can interfere with the ability of neurons in the brain to encode information and translate visual input into conscious thought, the researchers said. For example, when a sleep-deprived driver sees a pedestrian stepping in front of his car, it may take longer for the driver to realize what he or she is seeing because “the very act of seeing the pedestrian slows down in the driver’s overtired brain,” Nir said.

The researchers compared the effects of sleep deprivation to those of drunk driving.

“Inadequate sleep exerts a similar influence on our brain as drinking too much,” Fried said. “Yet no legal or medical standards exist for identifyingovertired drivers on the road the same way we target drunk drivers.”

The study was published yesterday (Nov. 6) in the journal Nature Medicine.

Originally published on Live Science.

Smallpox-Related Viruses Are Still a Threat to Humans, Experts Warn

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Smallpox-Related Viruses Are Still a Threat to Humans, Experts Warn

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Smallpox-Related Viruses Are Still a Threat to Humans, Experts Warn
An illustration of the smallpox virus.

Credit: decade3d – anatomy online/Shutterstock

Smallpox has been eradicated for decades, but other, related “poxviruses” are still around and continue to pose a risk to humans, experts say.

In fact, cases of human infection with viruses in the same family as thesmallpox virus are appearing in growing numbers.

What’s more, in recent years, researchers have discovered several never-before-seen poxviruses that cause illness in people. In one case, a woman in Alaska who thought she had a spider bite turned out to have an infection with a new poxvirus, and doctors never determined exactly how she became infected.

“Poxviruses continue to pose a threat,” Dr. Brett Petersen, a medical officer at the Centers for Disease Control and Prevention (CDC) Poxvirus and Rabies Branch, said during a talk at an infectious disease conference called IDWeek, held in San Diego earlier this month. For this reason, there is a “need for continued vigilance and increased surveillance” for cases of poxviruses, Petersen said. [The 9 Deadliest Viruses on Earth]

Poxviruses are oval or brick-shaped viruses with large genomes, according to the CDC. Infections with poxviruses typically cause skin lesions or rashes. Perhaps the most famous poxvirus, the variola virus, causes smallpox, a highly contagious and sometimes fatal disease that was declared eradicated from the world in 1980 thanks to a global vaccination campaign, according to the World Health Organization. (Eradication means that cases of the disease no longer occur naturally anywhere in the world.)

But after the eradication of smallpox, researchers saw an increase in cases of some other diseases caused by poxviruses. In particular, there has been a rise in cases of monkeypox, which is closely related to smallpox; both belong to the poxvirus family called orthopoxvirus. (The two diseases have similar symptoms, but monkeypox is less deadly than smallpox: The fatality rate for monkeypox is 10 percent, versus 30 percent for smallpox.)

Human cases of monkeypox occur primarily in Central and West Africa, and the virus is transmitted to humans from the fluids of animal carriers, including rodents and primates.

In a study published in 2010 in the Proceedings of the National Academy of Sciences, researchers found that since the eradication of smallpox, cases of monkeypox had increased 20-fold in the Democratic Republic of the Congo, from less than 1 case per 10,000 people in the 1980s to about 14 cases per 10,000 people in 2006-2007. [27 Devastating Infectious Diseases]

Other African countries have seen rises in monkeypox as well. In just the last month, 36 suspected cases of monkeypox have been reported in Nigeria, according to The Conversation. If confirmed, the cases would be the first in the country since 1978.

Doctors in the western world also have reason to be on the lookout for monkeypox and related poxviruses. In 2003, the United States experienced an outbreak of monkeypox tied to a shipment of animals from Ghana. In total, nearly 50 confirmed or probable cases of monkeypox were reported in six U.S. states during the outbreak, according to the CDC. “These diseases are never as far away as we think,” Petersen said.

Researchers also continue to discover new types of poxviruses in various parts of the world. In the Alaska case, which occurred in 2015, the woman went to the doctor because she had a lesion on her right shoulder, along with fever, fatigue and tender lymph nodes, according to a report of the case, published in June. Her doctors thought she might have chicken pox or shingles, but testing revealed that she had a type of orthopoxvirus that had never been seen before.

It took six months for the lesion to fully disappear, but the woman eventually recovered and did not transmit the infection to anyone else, the report said.

That case shows that there are “previously undiscovered, unrecognized, unknown poxviruses … that are still being discovered to this day,” Petersen said during his talk.

Efforts to discover exactly how the woman contracted the virus turned up empty. She had not traveled out of state, but her partner had traveled to Azerbaijan about four months earlier. Azerbaijan is next to the republic of Georgia, where another new orthopoxvirus was discovered, in 2013. But testing of her partner’s items from the trip, such as clothes and souvenirs he brought back, did not show any evidence of orthopoxvirus DNA.

Testing of small mammals near the woman’s home (such as shrews, voles and squirrels, which can carry orthopoxviruses), and testing of household areas that the small mammals may have touched, also came back negative. Still, the researchers said they were able to collect only a limited number of mammals from around the home. At this time, the most likely explanation for the patient’s infection is that she was exposed to the virus around where she lived, near Fairbanks, Alaska, the report said.

“This discovery of a novel orthopoxvirus is the latest in a growing number of reports of human poxvirus infection published in recent years,” the researchers said in their report.

One hypothesis for the increase in such infections is the cessation ofsmallpox vaccination, because such vaccination may have provided protection against other poxviruses, the researchers said.

“Continued emergence and re-emergence of orthopoxviruses is expected,” the researchers wrote.

Petersen also noted that even though smallpox has been eradicated, the virus that causes the disease has not been completely wiped off the planet. Some stocks of the virus still exist in labs in the United States and Russia. And there’s also concern that the virus could be used as a bioweapon. Earlier this year, scientists in Canada announced that they hadre-created the horsepox virus, a relative of smallpox, in a lab using DNA fragments. The findings suggest scientists could also make the smallpox virus in a lab.

“Unfortunately, we’re still talking about smallpox,” Petersen said. “[But] hopefully, we’ll never see another case.”

Original article on Live Science.

Sweet Lullaby: Scientists Uncover How Herpes Virus Sleeps and Wakes

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Sweet Lullaby: Scientists Uncover How Herpes Virus Sleeps and Wakes

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Sweet Lullaby: Scientists Uncover How Herpes Virus Sleeps and Wakes

A micrograph picture of the herpes simplex virus, within tissue taken from a penile lesion of a patient with genital herpes.

Credit: CDC

Viruses are tricky beasts. Some of these “submicroscopic” pathogens can “go to sleep” inside a person’s body, essentially hiding from the immune system indefinitely, only to reactivate and cause illness later.

Now, scientists have learned how to prevent one type of virus, the herpes virus, from slipping into its sleep-like dormant phase and out of sight. This is a major step in understanding the virus’s unique ability to essentially hide from the immune system, the scientists say.

More than 80 percent of the world’s population is infected with herpes simplex virus (HSV), according to the World Health Organization, which includes HSV-1, which causes cold sores, and HSV-2, which causes genital warts.

But most people who are infected with the virus have no symptoms until something external — stress, illness or even sunlight, for example — triggers the virus to wake up and start replicating and spreading. This, in turn, prompts the immune system to attack the virus, resulting in inflammation and the characteristic blisters around the mouth, lips, nose or genitals. It’s during this “reactivation” that the virus can spread from person to person. [The 9 Deadliest Viruses on Earth]

Unlike viruses such as those that cause the common cold or the flu, the herpes virus usually quickly enters a latent, or dormant, mode, in the human body. Scientists have tried to study this process. But in a laboratory setting, they have had difficulty placing the live virus to “sleep” without extreme and harmful measures, akin to clubbing your subject into an unconscious state and hoping it wakes up normally.

Now, in the first of two advances, scientists at Princeton University have developed a laboratory technique that more naturally induces the herpes virus into a latent mode, as gently as a lullaby, allowing them to better simulate the natural life cycle of the herpes virus. The same group of researchers then used this technique to find a key set of proteins involved in the virus’s tendency to sleep and wake.

The findings were published yesterday (Oct. 27) in the journal PLOS Pathogens.

Viruses that don’t quickly go into hiding are easier for the immune systemto find and kill. But this is not the case for the herpes viruses, which stay with you for life.

These viruses are part of a subfamily of the virus called alphaherpesvirinae, which is known to infect and then hide in nerve cells. The immune system has learned to treat these viruses with kid gloves, because immune cells can’t outright kill these herpes viruses without killing the nerve cells that serve as a host.

“Usually, killing a virus infection by the immune system involves killing the infected cells,” said senior study author Lynn Enquist, a professor in molecular biology at Princeton University. But “in this case, these cells would be the [nerve cells] that are irreplaceable. So, ‘putting the virus to sleep’ is a better and more protective way for the nervous system.”

A major question about herpes, however, is although the virus can sometimes cause symptoms immediately, why, most of the time, does it go into hiding right away?. The answer would reveal better ways to control infections.

To get to the heart of the issue — what causes the natural virus to stay awake and “escape from silencing,” as the researchers described it — the scientists used a type of herpesvirus called pseudorabies virus, which is closely related to HSV-1.

The researchers’ first step was to develop a method that would essentially put the virus to sleep in infected nerve cells. The technique involved using a novel three-chamber environment in which the nerve cell’s nucleus and its tentacle-like axon structures are isolated.

Then, the researchers focused on how to wake the virus up. They discovered two ways to do so: with chemical stress signals present at the time the virus enters the cells, as expected; or in the presence of a cluster of proteins called viral tegument proteins, a new concept.

Further analysis ruled out a hypothesis that perhaps it’s the size of the viral load, or the amount of virus in a person’s system, that somehow overrides the typical immune response to let the viruses sleep. Rather, the researchers found that the viral tegument proteins alone were the key trigger, acting like a splash of ice water on the face of the viruses, waking them up or otherwise keeping them awake and active.

“The question we and others are working on now is to determine if” this approach for waking viruses up in the lab is the same as what goes on naturally in the immune system when a virus wakes up, Enquist told Live Science. “We think there is a lot in common.” [Tiny & Nasty: Images of Things That Make Us Sick]

The Princeton researchers’ technique “represents an important advancement,” in studying the virus latency cycle and controlling infections, said Felicia Goodrum Sterling, an immunologist at the University of Arizona Cancer Center, who was not involved in the research.

“In understanding herpesvirus latency, model systems are everything,” Goodrum Sterling said. “This is the first model system that does not require drug treatment” to put viruses to sleep.

A better understanding of this mechanism, the researchers said, may lead to a class of drugs that could target viral tegument proteins to prevent them from waking up viruses or keeping them awake, thus preventing symptoms and the spreading of the virus to other people.

Follow Christopher Wanjek @wanjek for daily tweets on health and science with a humorous edge. Wanjek is the author of “Food at Work” and “Bad Medicine.” His column, Bad Medicine, appears regularly on Live Science.