Module Overview
The most numerous inhabitants of our planet are life forms whose size is far smaller than the resolution of the human eye. These microscopic organisms, generically called microbes, play a vital role in the ecology of the earth, and within our own bodies. In fact, we have a diverse ecosystem of microorganisms within us made up of about 100 trillion organisms in our digestive tract alone. In terms of cells, microbes out-number our own skin cells, muscle cells, neurons, and blood cells by about 300 to one! To learn more about what a microbe is, and our own microbiome, follow this link to a recent report from the American Academy of Microbiology, FAQ: Human Microbiome. You will need to read this to make your posts in your first Discussion.
As we learn more about the microbes in our microbiome, we will concentrate our attention on many of the microbes that are capable of altering our internal environment, making us sick. Infectious disorders are those caused by potentially dangerous microorganisms, called pathogens.
Infectious diseases have been a major threat to human health throughout history. Infections have killed more humans than all our armed conflicts combined. During most of our history, infections have been the main cause of death throughout the world. In spite of our spectacular accomplishments in the diagnosis, prevention, and management of these disorders, infections continue to be a major threat to the individual and collective health. Even though the mortality from infections has significantly decreased in the past decades, new challenges are emerging which require the clinical skills and sagacity from all primary health providers. Diseases which were considered to be on the verge of eradication are resurging with more aggressiveness. As with most health problems, prevention and early diagnosis are the most effective approaches to deal with these challenges.
Let us begin this course by defining some basic terms:
Microbiology is the branch of biology that studies microscopic life forms; their structure, taxonomy (classification), genetics, evolution, ecology, etc.
Clinical Microbiology, the main subject of this course, is a branch of the basic sciences in a health-related curriculum devoted to the study of microbial pathogens and their interaction with humans. Conventionally, Clinical Microbiology also studies viruses (incomplete life forms) and metazoan worms (that are not microscopic). In summary Clinical Microbiology is the discipline that deals with infectious disorders, in general.
Defense Mechanisms. The human body uses a series of strategies to prevent the entrance of these potentially dangerous microorganisms; these strategies are collectively called defense mechanisms and include the natural barriers, the process of inflammation, and the immune response. Were it not for these mechanisms we would be easy prey of the myria
d pathogens that surround us.
Pathogen. Any agent that is capable of causing disease. As applied to Microbiology, pathogens are the infectious agents.
Microorganisms. Microscopic life forms. Viruses (incomplete life forms) are also included in this category. Infectious agents of importance to humans include viruses, bacteria, fungi, protozoa, and multicellular infectious agents called metazoa (or helminths). Each of these groups of microorganisms is studied by a specific branch of microbiology: Virology, Bacteriology, Mycology, and Parasitology.
Host-microbe relations. The mutual interdependence of different life forms is called symbiosis. The interaction among two or more life forms may be beneficial for both, a mutualism, but in most cases one form will live at the expense of another. This type of symbiosis occurs between an infected human and the infectious agent and is called parasitism.
Types of Infectious Agents
Microbiology was a study of living organisms whose existence was difficult to prove to the general public. One of the reasons for this was that people could not see the organism; that is, not until the microscope was invented. Antony van Leeuwenhoek (1674 to 1724) was one of the pioneers in the making of microscopes. His observations are among the first recorded of bacteria, yeasts, and protozoa.
Edward Jenner is another important pioneer who made progress in developing vaccinations. Edward Jenner was a country doctor working in England around 1798. He observed that individuals who were exposed to cowpox, a virus related to smallpox that infects cattle, did not contract the smallpox virus. He was the first to use an artificial exposure to the cowpox virus to stimulate the human immune response. Edward Jenner’s early work put to use one of the first vaccinations for smallpox.
Although vaccines were used relatively early in the history of the science of microbiology, it is interesting to note that there were no systematic approaches to identifying the infectious agents until the end of the 19th century. Another pioneering scientist, Robert Koch (1890), is known for developing postulates that helped establish the agent for a particular disease. These postulates can be used for humans, animals, and plants for establishing the disease agent. They are still used today even though some complications and modifications must be used for certain obligate parasitic organisms (parasites that must live within a host).
Required Reading
Every Home page has valuable information that you are required to read. Your first two Case Assignments will focus on reading and accomplishing some research on the Home pages.
Your required reading can be found in your Microbiology etext available at londonessays.com
For your first Case Assignment, IN YOUR OWN WORDS, answer these questions reviewing the content in your Course Overview within the Syllabus: