According to the Centers for Disease Control and Prevention, viruses are not structured in the same way living cells are; they have no nucleus and no metabolism and do not reproduce on their own. In order for a virus to reproduce, it must take control of the cell it invades and force the cell to replicate the virus. When the mission is successful, the virus moves on to the next cell. Viruses are capable of causing serious infectious diseases in humans, plants and animals, and traditional antimicrobial treatments have no affect on them. Some of the more common human viruses are influenza, human papillomavirus, HIV, and hepatitis viruses A, B and C.
Influenza Viruses
Influenza viruses infect millions of men, women and children every year. The signs and symptoms of influenza may range from very mild to life threatening, depending on the patient and the virulence of the virus. Seasonal influenza is often seen in the months from October through March, while other influenza viruses, such as the H1N1, circulate year round. Influenza of any type is spread from person to person when an infected person coughs or sneezes in close proximity to another, who then inhales the virus into her lungs. Transmission also occurs from touching contaminated surfaces, then touching the mucous membranes of the eyes, nose or mouth.
Human Papillomavirus
The human papillomavirus, or HPV, affects over 50 percent of sexually active people in the United States, making it the most common sexually transmitted viral disease. According to the Centers for Disease Control and Prevention, there are more than forty types of sexually transmitted human papillomaviruses, many with links to several types of cancer in both men and women.
HIV/AIDS Virus
HIV, or the human immunodeficiency virus, destroys the body's immune system, inhibiting its ability to fight infection and disease. HIV leads to AIDS in the late stages when severe damage has occurred; at this stage, the badly impaired immune system is unable to fight many diseases, including some forms of cancer and tuberculosis.
Viral Hepatitis
Viral hepatitis attacks and infects the liver. The most common types of viral hepatitis are hepatitis A, B, and C. Hepatitis A is a self-limiting viral infection transmitted by ingestion of infectious matter, while types B and C are transmitted through contact with the blood and body fluids of infected persons. Chronic infection occurs in both types B and C but is more common with hepatitis C, the leading cause of liver cancer and liver transplants, according to the Centers for Disease Control and Prevention.
