Monthly Archives: June 2017

Why Lice Can Spread Lots of Diseases?

There’s a long list of diseases that you can get from a tick bite, including some that can actually kill you. In fact, the tiny bloodsucking critters can transmit a wider variety of bacteria, viruses and parasites than any other arthropod, a category that includes not only ticks but also insects such as mosquitoes.

More than 80 species of ticks are found in the United States, and about a dozen of these species can bite humans and are considered medically important, said Rebecca Eisen, a research biologist with the Centers for Disease Control and Prevention’s Division of Vector-Borne Diseases in Fort Collins, Colorado.

Moreover, infections from tick-borne diseases in the United States are increasing steadily, and the geographic range of ticks that transmit diseases is also expanding, Eisen told Live Science.

Geographically, the greatest expansion of deer ticks (which spread Lyme disease) has been observed in northeastern and north-central states, while remaining stable in southeastern states, according to a recent report on ticks by Eisen and her colleagues published in the Institute for Laboratory Animal Research (ILAR) journal. The expanded range of this tick may be a result of increasing populations of white-tailed deer, increasingly warmer temperatures and reforestation (the replanting of trees), experts say. [10 Important Ways to Avoid Summer Tick Bites]

As ticks spread into new areas and more cases of tick-related illnesses are reported each year, scientists are discovering new disease-causing agents spread by ticks, Eisen said. Since 2000, six new pathogens that cause disease in humans have been recognized in the United States, she said. For example, a new species of bacteria has recently been detected as a cause of Lyme disease in the upper Midwest that has not yet been found in the eastern U.S.

Ticks are known to spread nine bacterial diseases, such as Lyme disease(caused by the bacterium Borrelia burgdorferi) and Rocky Mountain spotted fever (caused by the bacterium Rickettsia rickettsia); four viral infections, including Powassan disease; and one illness linked with a parasite, babesiosis (Babesia microti).

Just three species of ticks are responsible for most U.S. cases of tick-related illness, Eisen said: the blacklegged tick (Ixodes scapularis); theLone Star tick (Amblyomma americanum) and the American dog tick (Dermacentor variabilis).

The blacklegged tick, also called the deer tick, is found in the northeastern and upper midwestern United States, and can transmit Lyme disease, babesiosis, anaplasmosis and Powassan disease. The Lone Star tick, which is found in the eastern and southeastern U.S., can spread tularemia. And the American dog tick is found mainly east of the Rocky Mountains and can transmit Rocky Mountain spotted fever.

Lyme disease is the most well-known tick-borne illness. People who catch it may develop a red-ringed “bull’s-eye” rash, along with flu-like symptoms. As the infection progresses, there may be facial-muscle paralysis or nerve pain. Each year, about 30,000 cases of Lyme disease are reported to the CDC, but because of unreported cases, the actual number of people in the U.S. with the disease is likely 10 times higher, Eisen said.

Troubling trends

What makes ticks so hospitable to such a wide array of disease-causing agents?

Ticks are parasites, so they have to feed on blood in order to reproduce, said Greg Ebel, a professor and director of the Arthropod-borne and Infectious Diseases Laboratory at Colorado State University in Fort Collins. This means ticks often associate with other animals because they need blood from these hosts to survive, he said.

For example, the ticks that are carriers of Lyme disease feed only one time during their larval stage, one time during their nymph stage and once in adulthood, Ebel told Live Science. They need each of these blood meals to molt and develop to their next stage of life, he explained.

Ticks don’t have wings, so they can’t fly, Ebel noted. In their early stages of development, larvae hang around in leaf piles, looking for mice and birds, and they can acquire infections by feeding on infected hosts, he said. Nymph and adult ticks may crawl onto blades of grass or shrubs. Nymphs may attach to medium-size animals, like chipmunks, and adult ticks may latch onto larger ones, like deer or dogs, Ebel said.  [Video: A Tick Bite Visualized]

Ticks typically spread disease by attaching to the skin of the host, which creates a wound, Ebel said; while ticks are taking a blood meal, they spit their infected saliva into the wound.

Adult female ticks may feed on a host for several days, which can increase their chances of picking up a pathogen that they may later pass along. And some disease-causing agents can be passed from infected female ticks into her eggs, so hatching larvae may already be infected.

Tick-bite prevention

Ticks are not specifically adapted to feed on people, Ebel said. For the most part, when a tick bites a human, it’s by accident, he said.

If, for example, a person is walking by tall grasses or thick vegetation, and a tick senses movement or warmth or smells carbon dioxide, the tick might attach to a human by mistake, thinking it’s an animal capable of giving it a blood meal, Ebel said.

Several factors may be contributing to the rise in tick-borne illnesses. There are more ticks in places where they have always been, and there are now ticks in places where they never were, Ebel said.

More ticks, of course, mean more tick bites.

In turn, there’s more transmission of disease-causing agents, but there is also increased awareness of tick-borne diseases among health professionals, as well as improved technologies to diagnose these illnesses, Ebel said.

Prevention can be challenging because ticks are difficult to control, Eisen said. Community-wide strategies to reduce the number of ticks — such as spraying vegetation with pesticides in areas where people are likely to encounter ticks or using deer fencing to keep animals away from homes — have not always been socially acceptable, she said.

But there are some steps people can take on their own to avoid tick bites:

  • Know which ticks are common in your area. Avoid places with thick vegetation, tall grass and leaf piles, where ticks often live, Eisen recommended.
  • Use insect repellent containingdiethyltoluamide (DEET). Put it on exposed skin when outdoors in areas that may be infested during the spring, summer and early fall, when ticks are most active.Treat clothing and camping gear with the insecticide permethrin, Eisen suggested.
  • Check for ticks. Shower as soon as possible after coming indoors, and check your body, clothes and gear for ticks. Treat dogs and cats with a product designed not to bring ticks into the home, Eisen said.

“The sooner a tick is found, the better a person’s odds are of not becoming infected,” Eisen said.

Pig-to-Human Transplantation CRISPR Genes Editing May Make This Possible

We are one step closer to having pig organ transplants, a new study shows.

Using the genetic cut-and-paste tool CRISPR, scientists have removed DNA-based viruses that usually infect pig organs, raising the chances that these animal organs could be safely transplanted into human patients one day, a process known as xenotransplantation.

Still, that doesn’t mean pig organ transplants are just around the corner; scientists would still need to change other elements of pig transplants to ensure the human body doesn’t reject them.

Currently, there is a dramatic shortage in the number of organ transplants available for people who need them, and many people die before they receive one. Animals such as pigs could theoretically supply an unlimited source of such organs. But immune incompatibilities and viruses that are incorporated into the pig genome, called porcine endogenous retroviruses (PERVs), have made it very likely that such pig organs would never take on their own. [11 Body Parts Grown in the Lab]

To get around those PERVs, scientists at eGenesis, a bioengineering company in Cambridge, Massachusetts, used CRISPR-Cas 9, a genetic tool that cuts the genome wherever it’s targeted, to remove 62 PERVs in pig cells in culture. The team then injected these cells into pig egg cells and generated baby pigs. They then used genetic testing to show that the pigs did not contain any trace of these PERVs.

“Although we have focused in this paper on the applications to xenotransplantation, we envision, more generally, that the synergistic combination of CRISPR-Cas technology with anti-apoptosis treatment may also be used to enable large-scale genome engineering in primary cells for a broad range of applications,” the researchers wrote in the study, which was published yesterday (Aug. 10) in the journal Science.

Opioid Crisis Is a National Emergency, What Happens Now?

President Donald Trump has declared the opioid epidemic a “national emergency,” but what happens now, and could this declaration really help address the crisis?

On Thursday (Aug. 10), Trump told reporters that the opioid epidemic is a national emergency. “We’re going to spend a lot of time, a lot of effort and a lot of money on the opioid crisis,” he said.

In a statement, the White House said Trump had ” instructed his administration to use all appropriate emergency and other authorities to respond to the crisis caused by the opioid epidemic.”

The declaration follows a recommendation from Trump’s commission on the opioid crisis, which urged the president to declare a national emergency over the issue.

Experts said that the declaration was encouraging, but it’s uncertain how big of an impact it will have on the opioid crisis.

“To me it’s an important step, [but] there need to be many steps after this,” said Dr. Bradley Stein, a psychiatrist and senior physician policy researcher at the RAND Corporation, a nonprofit research organization. Stein noted that the opioid epidemic has evolved over decades and is not something that can be solved overnight. “There’s not really a silver bullet here — there’s not really a single policy that’s going to solve this. We as a country need to attack it at multiple fronts,” Stein told Live Science. [America’s Opioid-Use Epidemic: 5 Startling Facts]

Since 1999, the number of people who have died from overdoses of either prescription opioids or heroin has nearly quadrupled in the United States, according to the Centers for Disease Control and Prevention (CDC). Currently, about 1,000 Americans die per week from drug overdose (not just from opioids), according to a statement from Trump’s opioid commission. And in 2015, opioids (prescription and heroin) killed more than 33,000 people, more than in any other year on record, according to the CDC.

Declaring a national emergency does bring attention to the issue, Stein said. “It certainly sends a signal about the level of federal commitment to addressing this crisis,” he said.

The declaration could also open up more resources for addressing the epidemic. But exactly which resources become available will depend upon which path the administration takes for this emergency declaration.

The administration can declare an emergency in two ways: through the Stafford Act or through the Public Health Service Act, and each of these laws could help in different ways, Stein said.

A declaration through the Stafford Act would trigger the same type of aid that is available to areas after a natural disaster. This means money from the federal disaster-relief fund could be used to bolster efforts to treat opioid addiction or prevent misuse of these drugs, Stein said.

However, money from the disaster-relief fund would be limited; in total, there is currently $1.4 billion available through the fund for aiding disasters over the rest of the year. This could be enough to get some efforts started in the short term, but ultimately, a more long-term investment would be needed, Stein said.

A declaration through the Public Health Service Act could help increase access to opioid treatment in underserved areas by making it easier for doctors to practice medicine in different states, Stein said. Rather than having to go through a lengthy process to obtain a medical license in a different state, a doctor moving to an underserved area would have some of these requirements waived.

A particularly promising benefit of the “national emergency” declaration (regardless of which act is invoked) could be to allow states more flexibility in using funds from Medicaid for treating opioid disorders. For example, currently, Medicaid can’t be used to reimburse treatments at psychiatric facilities, where some people with opioid disorder receive treatment, Stein said. But this barrier could be waived using either the Stafford Act or the Public Health Service Act.

“That would open up more resources [and] more facilities to be able to treat opioid disorders,” Stein said.

As for next steps, Stein said there should be a focus on not only increasing access to treatment for opioid disorders, but also making sure the treatment is of high quality. In addition, more efforts are needed to reduce access to these powerful drugs, through both prescriptions and illegal markets, he said.

“Neither of those things happen[s] overnight … but we can make progress” over the long term, Stein said.

Finally, when new policies are put into place to address the opioid epidemic, it’s important to revisit these policies from time to time to make sure they are working and not having unintended consequences, Stein said. For example, in recent years, the Food and Drug Administration approved newer formulations of opioids that were harder to abuse, but as a result, some people shifted to using heroin instead, Stein said.

“We can’t put things in place and walk away,” Stein said. “We may need to modify some of our responses” to the epidemic.

What is MRI (Magnetic Resonance Imaging)? Here’s his Explanation!

Magnetic resonance imaging (MRI), also known as nuclear magnetic resonance imaging, is a scanning technique for creating detailed images of the human body.

The scan uses a strong magnetic field and radio waves to generate images of parts of the body that can’t be seen as well with X-rays, CT scans or ultrasound. For example, it can help doctors to see inside joints, cartilage, ligaments, muscles and tendons, which makes it helpful for detecting various sports injuries.

MRI is also used to examine internal body structures and diagnose a variety of disorders, such as strokes, tumors, aneurysms, spinal cord injuries, multiple sclerosis and eye or inner ear problems, according to the Mayo Clinic. It is also widely used in research to measure brain structure and function, among other things.

“What makes MRI so powerful is, you have really exquisite soft tissue, and anatomic, detail,” said Dr. Christopher Filippi, a diagnostic radiologist at North Shore University Hospital, Manhasset, New York. The biggest benefit of MRI compared with other imaging techniques (such as CT scans and x-rays) is, there’s no risk of being exposed to radiation, Filippi told Live Science.

During an MRI, a person will be asked to lie on a movable table that will slide into a doughnut-shaped opening of the machine to scan a specific portion of your body. The machine itself will generate a strong magnetic field around the person and radio waves will be directed at the body, according to the Mayo Clinic.

A person will not feel the magnetic field or radio waves, so the procedure itself is painless. However, there may be a lot of loud thumping or tapping noises during the scan (it may sound like a sledgehammer!), so people are often given headphones to listen to music or earplugs to help block the sound. A technician may also give instructions to you during the test.

Some people may be given a contrast solution by intravenous, a liquid dye that can highlight specific problems that might not show up otherwise on the scan.

Young children as well as people who feel claustrophobic in enclosed places may be given sedating medication to help them relax or fall asleep during the scan because it is important to stay as still as possible to get clear images. Movement can blur the images.

Some hospitals might have an open MRI machine that is open on the sides rather than the tunnel-like tube found in a traditional machine. This may be a helpful alternative for people who feel afraid of confined spaces.

The scan itself may take 30 to 60 minutes, on average, according to the American Academy of Family Physicians.

A radiologist will look at the images and send a report to your doctor with your test results.

The human body is mostly water. Water molecules (H2O) contain hydrogen nuclei (protons), which become aligned in a magnetic field. An MRI scanner applies a very strong magnetic field (about 0.2 to 3 teslas, or roughly a thousand times the strength of a typical fridge magnet), which aligns the proton “spins.”

The scanner also produces a radio frequency current that creates a varying magnetic field. The protons absorb the energy from the magnetic field and flip their spins. When the field is turned off, the protons gradually return to their normal spin, a process called precession. The return process produces a radio signal that can be measured by receivers in the scanner and made into an image, Filippi explained.

Protons in different body tissues return to their normal spins at different rates, so the scanner can distinguish among various types of tissue. The scanner settings can be adjusted to produce contrasts between different body tissues. Additional magnetic fields are used to produce 3-dimensional images that may be viewed from different angles. There are many forms of MRI, but diffusion MRI and functional MRI (fMRI) are two of the most common.

This form of MRI measures how water molecules diffuse through body tissues. Certain disease processes — such as a stroke or tumor — can restrict this diffusion, so this method is often used to diagnose them, Filippi said. Diffusion MRI has only been around for about 15 to 20 years, he added.

In addition to structural imaging, MRI can also be used to visualize functional activity in the brain. Functional MRI, or fMRI, measures changes in blood flow to different parts of the brain.

It is used to observe brain structures and to determine which parts of the brain are handling critical functions. Functional MRI may also be used to evaluate damage from a head injury or Alzheimer’s disease. fMRI has been especially useful in neuroscience — “It has really revolutionized how we study the brain,” Filippi told Live Science.

Unlike other imaging forms like X-rays or CT scans, MRI doesn’t use ionizing radiation. MRI is increasingly being used to image fetuses during pregnancy, and no adverse effects on the fetus have been demonstrated, Filippi said.

Still, the procedure can have risks, and medical societies don’t recommend using MRI as the first stage of diagnosis.

Because MRI uses strong magnets, any kind of metal implant, such as a pacemaker, artificial joints, artificial heart valves, cochlear implants or metal plates, screws or rods, pose a hazard. The implant can move or heat up in the magnetic field.

Several patients with pacemakers who underwent MRI scans have died, patients should always be asked about any implants before getting scanned. Many implants today are “MR-safe,” however, Filippi said.

The constant flipping of magnetic fields can produce loud clicking or beeping noises, so ear protection is necessary during the scan.