Patents are designed to protect creations and designs, but how long a patent lasts for is dependent on a number of factors. The length of time that a patent offers protection, depends largely on what type of patent is issued and whether required maintenance fees are paid to keep the patent active. slide 1 of 6.
A viral infection is a disease that can be caused by different kinds of viruses, of which the influenza-virus is best known.
URL of this page: //medlineplus.gov/ency/article/000416.htm. Viral arthritis is swelling and irritation (inflammation) of a joint caused by a viral infection. Arthritis may be a symptom of many virus-related illnesses.