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via TheWorldNewsOrgWorld News

via TheWorldNewsOrgWorld News

What could be more alien than a virus? It’s a nanobiological weapon — a microscopic protein shell holding a few genes that hijack a cell’s internal machinery, forcing it to make new viruses. The battles we fight with these alien enemies brings malaise, scars and even death. Yet as foreign as viruses may seem, the boundary between us and them is turning out to be remarkably blurry. We use DNA from viruses to do things that are essential to our own survival, scientists are finding. Somehow, we have managed to domesticate some of these invaders. A number of viruses replicate by inserting their DNA into our own genes. On rare occasions, their genes get passed down to future generations. At first, the newly acquired genes behave a lot like regular virus genes. They can still coax host cells to make full-fledged viruses that can escape and infect other victims. But over the generations, they lose the ability to escape human cells. They can still make copies of themselves, but those copies get incorporated into the host cell’s DNA. Over time these so-called endogenous retroviruses lose even the ability to replicate, becoming harmless fragments adrift in the human genome. Endogenous retroviruses first invaded the cells of our primate ancestors more than 50 million years ago. Scientists have identified over 100,000 of these fragments in the human genome, accounting for 8 percent of our DNA. Some of these fragments have become part of our biology and perform tasks that benefit us. “A host essentially takes over a viral gene and puts it to work for its own ends,” said Aris Katzourakis, an evolutionary biologist at the University of Oxford. Human cells may have even co-opted viral DNA for a particularly ironic purpose: to fight other viruses. Twenty years ago, British scientists investigated a virus-fighting protein called Fv1. It protects mice by latching onto invading viruses and preventing them from inserting their DNA into the genome of a mouse cell. The gene that encodes Fv1 came originally from a mouse-infecting virus, the researchers discovered. Other proteins produced by viral DNA block the receptors through which newcomer viruses invade. Some viral proteins disrupt the replication of attacking viruses, leaving them unable to invade other cells. On Thursday in the journal Science, scientists reported that human ancestors also harnessed viral DNA to rewire their own genetic circuitry. Guillaume Bourque, a geneticist at McGill University who was not involved in the study, praised it for revealing a new way in which evolution harnessed viral DNA to strengthen the immune system. “In that sense, it’s a first,” he said. To fight invading viruses, a cell needs to turn on many genes at once. The genetic switches that make this possible are stretches of DNA next to each gene, which are themselves activated by proteins. From left, University of Utah geneticists Cedric Feschotte, Edward Chuong and Nels Elde. Their research suggests that viral DNA fragments in the human genome may help fight viral infections. UNIVERSITY OF UTAH HEALTH SCIENCES One such protein is interferon, which is produced when a cell is attacked by a virus. Interferon turns on genes that cells use to defend themselves. Cedric Feschotte and his colleagues at the University of Utah wondered if our cells harnessed viral gene switches to turn on immune genes. They discovered many pieces of viral DNA sitting next to genes that belong to the interferon network. The scientists edited the DNA of human cells they grew in a dish, chopping out some of the viral switches near interferon-responsive genes. Then they exposed those cells to interferon. The immunity genes, they found, barely woke up. In another experiment, the team exposed the altered cells to viruses and found that the cells mounted only a weak defense. “They became more susceptible to infection,” Dr. Feschotte said. The results suggest that many of the gene switches that help defend our cells from viruses actually came from viruses. Dr. Feschotte noted that a number of viruses that infect humans today have gene switches that turn on their genes when they sense their host cells have launched an interferon defense. Such gene switches would have been easily captured by our own cells. The new study adds even more evidence of the importance of viral DNA in our evolution. By spreading their DNA around our genome, viruses provided us with new switches that our cells could harness. But understanding the full effect of viruses on our evolution will take years, according to Dr. Feschotte. “It’s the sort of thing that I think about night and day,” he said. Source: http://mobile.nytimes.com/2016/03/03/science/study-finds-surprising-benefit-of-viral-dna-fighting-other-viruses.html

Zika virus is spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil. The outbreak in Brazil led to reports of Guillain-Barré syndrome and pregnant women giving birth to babies with birth defects and poor pregnancy outcomes. In response, CDC has issued travel notices for people traveling to regions and certain countries where Zika virus transmission is ongoing. Symptoms About 1 in 5 people infected with Zika virus become ill (i.e., develop Zika). The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes). Other common symptoms include muscle pain and headache. The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week. The illness is usually mild with symptoms lasting for several days to a week. Zika virus usually remains in the blood of an infected person for a few days but it can be found longer in some people. Severe disease requiring hospitalization is uncommon. Deaths are rare. Diagnosis The symptoms of Zika are similar to those of dengue and chikungunya, diseases spread through the same mosquitoes that transmit Zika. See your healthcare provider if you develop the symptoms described above and have visited an area where Zika is found. If you have recently traveled, tell your healthcare provider when and where you traveled. Your healthcare provider may order blood tests to look for Zika or other similar viruses like dengue or chikungunya. Treatment No vaccine or medications are available to prevent or treat Zika infections. Treat the symptoms: Get plenty of rest. Drink fluids to prevent dehydration. Take medicine such as acetaminophen to relieve fever and pain. Do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen and naproxen. Aspirin and NSAIDs should be avoided until dengue can be ruled out to reduce the risk of hemorrhage (bleeding). If you are taking medicine for another medical condition, talk to your healthcare provider before taking additional medication. If you have Zika, prevent mosquito bites for the first week of your illness. During the first week of infection, Zika virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites. An infected mosquito can then spread the virus to other people. Prevention No vaccine exists to prevent Zika virus disease (Zika). Prevent Zika by avoiding mosquito bites (see below). Mosquitoes that spread Zika virus bite mostly during the daytime. Mosquitoes that spread Zika virus also spread dengue and chikungunya viruses. When traveling to countries where Zika virus or other viruses spread by mosquitoes are found, take the following steps: Wear long-sleeved shirts and long pants. Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside. Sleep under a mosquito bed net if you are overseas or outside and are not able to protect yourself from mosquito bites. Use Environmental Protection Agency (EPA)-registered insect repellents. All EPA-registered insect repellents are evaluated for effectiveness. Always follow the product label instructions Reapply insect repellent as directed. Do not spray repellent on the skin under clothing. If you are also using sunscreen, apply sunscreen before applying insect repellent. If you have a baby or child: Do not use insect repellent on babies younger than 2 months of age. Dress your child in clothing that covers arms and legs, or Cover crib, stroller, and baby carrier with mosquito netting. Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin. Adults: Spray insect repellent onto your hands and then apply to a child’s face. Treat clothing and gear with permethrin or purchase permethrin-treated items. Treated clothing remains protective after multiple washings. See product information to learn how long the protection will last. If treating items yourself, follow the product instructions carefully. Do NOT use permethrin products directly on skin. They are intended to treat clothing. If you have Zika, protect others from getting sick During the first week of infection, Zika virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites. An infected mosquito can then spread the virus to other people. To help prevent others from getting sick, avoid mosquito bites during the first week of illness. Source: http://www.cdc.gov/zika/