| Viral infection: Infection caused by the presence | | | | Viral infections in small children can be more |
| of a virus in the body. Depending on the virus and | | | | difficult to deal with simply because children tend |
| the person's state of health, various viruses can | | | | to be cranky when they are ill. Soothing their |
| infect almost any type of body tissue, from the | | | | symptoms as they arise can help them cope with |
| brain to the skin. Viral infections cannot be treated | | | | the illness. Adults who contract viral infections |
| with antibiotics; in fact, in some cases the use of | | | | should listen to their body. Sleeping as needed and |
| antibiotics makes the infection worse. The vast | | | | drinking ample fluids can help the body fight off |
| majority of human viral infections can be | | | | the viral infection faster. Viral infections should be |
| effectively fought by the body's own immune | | | | diagnosed by a physician. |
| system, with a little help in the form of proper | | | | Rotaviruses are a group of viruses that can cause |
| diet, hydration, and rest. | | | | severe viral gastroenteritis in infants and young |
| Common viral infections may be diagnosed based | | | | children. They cause about half of all hospitalised |
| on symptoms. For infections that occur in | | | | cases of gastroenteritis in children less than five |
| epidemics (such as influenza), the presence of | | | | years of age. In temperate climates, ... |
| other similar cases may help doctors identify a | | | | Unlike bacteria, viruses are not "living" organisms |
| particular infection. For other infections, blood | | | | but capsules of genetic material. They require |
| tests and cultures (growing microorganisms in the | | | | living hosts — such as people, plants or animals |
| laboratory from samples of blood, body fluid, or | | | | — to multiply. Otherwise, they can't survive. |
| other material taken from an infected area) may | | | | When a virus enters your body, it invades some |
| be done. Blood may be tested for antibodies to | | | | of your cells and takes over the cell machinery, |
| viruses or for antigens (proteins on or in viruses | | | | redirecting it to produce the virus. The virus may |
| that trigger the body's defenses). | | | | eventually kill the host cells. Some viral infections, |
| Viral infections are hard to treat because viruses | | | | such as influenza and HIV, are contagious. Others |
| live inside your body's cells. They are "protected" | | | | are not. |
| from medicines, which usually move through your | | | | Viral infections can produce inflammation of the |
| bloodstream. Antibiotics do not work for viral | | | | meninges (causing viral meningitis), the brain |
| infections. There are a few antiviral medicines | | | | (causing viral encephalitis), the spinal cord (causing |
| available. Vaccines can help prevent you from | | | | myelitis), or spinal nerve roots (causing shingles). |
| getting many viral diseases. | | | | Viral encephalitis is often accompanied by viral |
| The body has a number of defenses against | | | | meningitis. Viral encephalitis is more serious |
| viruses. Physical barriers, such as the skin, | | | | because it directly affects the brain rather than |
| discourage easy entry. Infected cells also make | | | | the meninges. |
| interferons, substances that can make uninfected | | | | Some viral infections are mild, causing fever and a |
| cells more resistant to infection by many viruses. | | | | general feeling of illness (malaise), often without |
| Viral infections are caused by the virus. The virus | | | | specific symptoms. Usually, viral meningitis |
| enters the body through swallowing, inhalation, | | | | produces symptoms that are similar to those of |
| infected food, transfer from human to human | | | | bacterial meningitis (fever, headache, vomiting, |
| contact, or transfer from insect bites. The instant | | | | weakness, and a stiff neck) but that are much |
| the virus has entered the body, the immune | | | | less severe. |
| system immediately tries to rid the alien particle | | | | Yellow fever is a serious viral disease transmitted |
| from the system. Sometimes the immune | | | | by mosquitoes in parts of Africa and South |
| system wins and sometimes the virus begins to | | | | America. Vaccination is a legal requirement for |
| attach itself to an available cell. | | | | people travelling through infected areas. |