VirusAn invisible organism enters your body. It enters your tissues and then takes control of your own cells' machinery to produce more copies of itself. This little infiltrator works silently, producing thousands of these clones that fill the cell and cause it to explode. The clones mercilessly continue the process of invading, taking over and destroying cells. The result could be a minor inconvenience to you as the host, or result in a slow or quick death. It just depends on which variant of this unwanted infiltrator overcomes your body's defenses. There are remedies to eliminate certain types of these invisible intruders, but others are so difficult to eradicate or so easily adaptable that the world's greatest scientists have failed to defeat them. This isn't the start of a medical thriller; it is simply a description of common viruses that surround and infect us every day. From colds to cancers, viruses plague humans with disease and misery. Some of them, like the flu, adapt and evolve as quickly as defenses are built against them. Some enter cells and immediately start their replication. Others lie dormant as opportunistic predators until conditions are right for them to spread. Herpes viruses can do this over and over again. They hide in nerve tissue until they erupt, leaving painful ulcers when the host tissue is destroyed. The human papillomavirus (HPV) causes genital warts and predisposes its victims to cervical cancer. Likewise, hepatitis viruses, particularly hepatitis C, can make a patient vulnerable to liver cancer. Other cancers in humans are also known to be caused by viruses. It is tempting to attribute human traits to viruses by considering them artificial and evil. But, they...... middle of paper...... enter your body. Some vaccines, such as those against polio, measles and smallpox, have been shown to be very effective in eliminating the causative pathogens from the population. Other viruses, including HIV, influenza and those that cause the common cold, are capable of changing enough to escape recognition by responding antibodies, making current vaccines useless. Antiviral drugs seek out and destroy viruses by recognizing unique components of the capsid or envelope. Herpes viruses can be somewhat controlled, but not eliminated in this way. The infections are shorter, but the virus is still waiting in the nerve cells to reappear another day. Anti-HIV treatments have extended the life expectancy of patients infected with the human immunodeficiency virus by suppressing multiplication within the host. Viruses prove that truth is stranger than (science) fiction.