Different viruses attack certain cells in your body such as your liver, respiratory system, or blood. When you get a virus, you may not always get sick from it. Your immune system may be able to fight it off. For most viral infections, treatments can only help with symptoms while you wait for your immune system to fight off the virus. Antibiotics do not work for viral infections. There are antiviral medicines to treat some viral infections. Vaccines can help prevent you from getting many viral diseases.
The information on this site should not be used as a substitute for professional medical care or advice. In other words, this virus is good at getting its genetic information genes into human cells. What if its genes were replaced with human genes related to disease? Could we cure genetic disease by giving cells a healthy copy of the mutated gene? These questions helped spark the field of gene therapy. This drug, Luxturna, is for patients with a rare form of inherited vision loss that could cause blindness.
In this disease, an essential enzyme for normal eye development is missing due to a mutation in the RPE65 gene. A gene of viral origin encodes for a protein that plays a key role in long-term memory formation by moving information between cells in the nervous system. Ancient retroviruses are responsible for the human ability to have live births Credit: Getty Images. The most striking example, though, relates to the evolution of the mammalian placenta and the timing of gene expression in human pregnancy.
Evidence indicates that we owe our ability to have live births to a bit of genetic code that was co-opted from ancient retroviruses that infected our ancestors more than million years ago. Experts believe that such signatures occur throughout all forms of multi-cellular life. Scientists have only just begun to discover the ways that viruses help to sustain life, because they have only just begun to look.
Ultimately, though, the more we learn about all viruses, not just the pathogens, the better equipped we will be to harness certain viruses for good and to develop defenses against others that could lead to the next pandemic.
More than that, learning more about the wealth of viral diversity will help us unlock a deeper understanding of how our planet, ecosystems and very bodies work. Join one million Future fans by liking us on Facebook , or follow us on Twitter or Instagram. If you liked this story, sign up for the weekly bbc. What If Why the world needs viruses to function. Share using Email. By Rachel Nuwer 18th June If all viruses disappeared, the world would be very different — and not necessarily for the better.
But what exactly would happen? The flu that transformed the 20th Century How will coronavirus change the world? This is probably a survival strategy; when the host bacterium divides, creating a copy of its genome, it copies the phage genome as well. In this model, the survival of the host determines the survival of the phage, so the phage has a vested interest in maintaining its host.
It is clear why such a strategy benefits the phage but not so clear how it could benefit the bacteria. For whatever reason, it seems that many bacteria in the body have grown accustomed to living with their phages. When the opportunity arises, hibernating phages may awaken and produce many progeny, killing their host cells.
Sometimes the exiting phages take bacterial genes along with them. This payload can at times benefit the next bacteria the phages infect. I have found phages in saliva, for example, carrying genes that help bacteria evade our immune system. Some phages even carry genes that help bacteria resist antibiotics. Phages have no need for such genes, because phages cannot be killed by antibiotics, so when they provide the genes to bacteria they promote the hosts' survival—synonymous with survival of the phages.
We see these kinds of transfers often. Phages can take protection of their host further. The bacterium Pseudomonas aeruginosa , best known for causing pneumonia, triggers a number of illnesses. People who have lung diseases such as cystic fibrosis find it nearly impossible to clear this bacterium from their lungs, even when taking antibiotics designed to kill it.
Some P. In researchers led by a group at Stanford, including Elizabeth Burgener and Paul Bollyky, discovered that filamentous phages can form a protective cloak—layers of carbohydrates and proteins that help bacteria hide from antibiotics. This allows the bacteria to shelter in place until the antibiotics go away, living to cause infection another day. It is not a big leap to wonder whether we can harness the viruses living within us to improve our health.
We have already found a few cases in which this happens naturally. As phages move around the body looking for bacteria, some of them bind to cells on the surface of mucosal membranes, such as those that line the nose, throat, stomach and intestines. The phages cannot replicate there, but they can lie in wait for a vulnerable host to come by. This process could theoretically protect us from some illnesses.
Say you eat food contaminated with Salmonella bacteria. If the bacteria brush along the stomach's membrane, phages there could ostensibly infect the bacteria and kill them before they can cause disease. In this way, phages may serve as a de facto immune system that protects us against disease. No one has proved this yet, but in a research group in Finland showed that phages bound to mucus in pigs and rainbow trout persisted there for seven days and protected against one kind of bacterium that infects these animals.
One phage getting a lot of attention is crAssphage, discovered in by Bas Dutilh of the Radboud Institute in the Netherlands. Studies since then have shown that it inhabits most people around the world—except, it seems, for traditional hunter-gatherer populations.
It is unusual to find the exact same virus spread so far and wide, and no one has linked it to any disease. Scientists think it controls the prevalence of a common gut bacterium called Bacteroides.
If so, we might be able to exploit it to improve gastrointestinal conditions. It is so prevalent in human feces that researchers now test for it in drinking water to see if the water has been contaminated by sewage. Physicians are especially interested in phages that might counteract the aggressive rise of antibiotic-resistant bacteria. Development of new antibiotics has failed to keep pace. The World Health Organization estimates that by these pathogens will cause at least 10 million deaths annually, so alternative therapies are vital.
Phages were discovered more than years ago, and physicians tried to use them to treat bacteria that cause disease, though without great success.
In the s antibiotics replaced phages in most of the world because the drugs were much more effective and much easier to use. Now some medical researchers, such as the Rockefeller University investigators who used a phage enzyme to fight methicillin-resistant Staphylococcus infection, are taking a new look at phages. For years most physicians have been afraid to administer phages because they did not know whether the human immune system would overreact, causing dangerous levels of inflammation.
0コメント