Two_Pathogens_That_Cause_Infectious_Diseases

COM/155 Author: Avril Mclean Date: April 14, 2013 Two Pathogens That Cause Infectious Diseases Pathogens viral or bacterial, infects microorganisms and occurs between hosts of the same or opposite species, but have different pathways to invade humans, animals, and plants. Bacteria and viruses are everywhere, but only a few cause disease. These disease causing agent can be considered a conflict between the pathogen and the host. The goal of this paper is to show the origin and effect of these two pathogens, and ways the host can fight invasion. Virus Viruses are not able to grow or reproduce on their own, but must take over a host’s cell that provides these functions; Therefore, a virus is not considered “living.” However, the structure of a virus is extremely simple and sufficient for an independent life. Viruses can be made up of either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). Unlike living cells, viruses will have either DNA or RNA, but not both. All viruses reproduce by infecting living cells, resulting in a disease when the infection causes harm to the host. A virus’s sole purpose is to reproduce, but it needs a host to do so. Once a suitable host cell has been located, the virus attaches to the surface of the cell or is ingested into the cell by a process called “phagocytosis.” It then releases its genetic material into the cell, and essentially shuts down normal cell processes. The cell stops producing the proteins that it usually makes and uses the new blueprint provided by the virus to begin making viral proteins. The virus uses the cell’s energy and materials to produce the nucleic acid to make numerous copies of the original virus. Once these clones are assembled, the virus will cause the hosts cell to rupture, releasing the viruses to infect neighboring cells. Viruses are known to affect any kind of hosts that has living cells. Animals, plants, fungi and bacteria are all subject to viral infection. They tend to be some what particular about the type of cells they infect. Plant viruses are not equipped to infect animal cells ( Forrester & Smith MD’s), for example, a certain plant virus could infect a number of related plants. Sometimes a virus may infect one creature and do no harm, but will cause havoc when it gets into a different but closely related creature. For example, deer mice carry the Hantavirus without much noticeable effects on the rodents, but if Hantavirus infects a person, it causes a dramatic, and frequently deadly disease marked by excessive bleeding (Billings West). However, most animal viruses are species specific. This means, they will infect one species of animals. For instance, feline immunodeficiency virus (FIV) will only infect cats; human immunodeficiency virus (HIV) will only infect humans (Dr Foster & Smith). Ways In Which The Hosts Can Fight Invasion of a Virus Any foreign substance introduced into the body produces what is called an “immune response.” Through this process, the host’s body produces antibodies. Antibodies are substances that will destroy an invader and prevent the host from contracting the same disease again (billingswest.billings). Antibodies are specific to each invader, and each time that a new disease is contracted, a new set of antibodies will have to be manufactured. There are some antiviral medications that can be administered in the case of viral infection, but the body’s immune system is largely relied upon to fight off these kind of infections. Bacteria Although different from viruses, the largest is only as big as the largest bacterium (singular for bacteria), can be found living on almost any surface and in almost any =climate in the world, are microscopic and cannot be seen with the naked eye (Foster & Smith MD). These microbes have been around for billions of years because they are able to adapt to the ever-changing environment. They are so small that the sizes are measured in micrometers, and can find a home anywhere, and some of them live in places where it was once thought “nothing” could survive. There are bacteria in the soil , at the depths of the ocean, living in the mouth of volcanoes, on the surfaces of teeth, and in the digestive tracts of humans and animals. Though more complex than a virus, the structure of a bacterium is still relatively simple. On the other hand, the growth of pathogenic bacteria disrupts the body’s equilibrium by interfering with its normal activities thus producing a disease (Billings West). Bacteria produce disease in one of two general ways. Using Cells For Food Some bacteria damage the cells and tissues of infected organism directly by breaking down the cells for food example, mycobacterium tuberculosis, which causes tuberculosis, is inhaled into the lungs where it destroys the lung tissue. The bacterium also may enter a blood vessel and travel to new sites in the body where it destroys more tissues. Releasing Toxins Other bacteria releases toxins (poisons) that travels throughout the body interfering with the normal activities of the host, for example, the streptococcus bacterium that causes strep throat can release toxins into the bloodstreams causing scarlet fever. Diphtheria is another disease that release toxins into the bloodstream where they destroy tissues leading to breathing problems, heart failure, paralysis and death. In contrast, the bacteria Clostridium Tetanic (causes tetanus) is not very evasive but it produces a potent toxin that causes damage at a very small concentration. Ways in Which The Body Fights off Bacteria Infection The body mounts an immune response to the foreign invader, producing antibodies for immediate help and future protection. This process takes about a week while antibodies are employed in the mean time. Antibiotic drugs are usually only successful in treating bacterial infections, not viral infections. Bacteria are very resilient and have already developed resistance to many antibiotics. Many bacteria lives on and within our bodies and are thought of as a bad thing, but most are not pathogenic. In fact, many bacteria are very helpful to us. Some bacteria species help to perform essential functions such as digesting our food, decompose trash, clean up oil spills, and even produce medicines. However a few species are pathogenic and gives the rest of the bacteria a bad name. Ref: Billings West Forrester & Smith MDs Avril Mclean, Student, UoP