One of the most important things you will learn in this course is what I call the "Big Picture of Infectious Diseases," or as was just mentioned, the biological basis of host parasite interaction. There are three interlocking parts to this big picture:
1. The microbe's side of the story - why some microbes have more potential to be harmful.
2. The body's side of the story - ways in which the body is able to defend itself naturally against infectious disease agents.
3. Ways in which we can artificially help the body defend itself by removing the microbes or enhancing body defenses.
A. The microbe's side of the story - why some microbes have more potential to be harmful.
The overwhelming majority of microbes are harmless to humans and, in fact, many are beneficial, being key players in the recycling of nutrients in nature. We will look at the major groups of microbes, learn what they are composed of chemically and structurally, and see how how they carry out their metabolism and reproduce. We will learn of a variety of factors some microbes may possess that play a role in increasing their ability to cause disease. Also we will learn how, through mutation, genetic recombination, and natural selection, microbes may adapt to resist our control attempts.
B. The body's side of the story - ways in which the body is able to defend itself naturally against infectious disease agents.
Here will learn about the phenomenal defenses the body has available to defend itself against infectious disease agents, as well as altered body cells such as cancer cells and infected cells. The body is able to do this through the innate immune system and the adaptive immune system. Innate immune defenses are those you are born with and include anatomical barriers, mechanical removal, cytokines, pattern-recognition receptors, phagocytosis, inflammation, the complement pathways, and fever. The adaptive immune defenses are those you develop throughout your life and include antibody production and cell-mediated immunity.
C. Ways in which we can artificially help the body defend itself by removing the microbes or enhancing body defenses.
We will learn how we can artificially help ourselves to avoid or reduce the risk of infection. Also we will learn ways in which we are able to artificially remove microbes from the body and its environment using agents such as antiseptics, disinfectants, physical agents such as heat and cold, antimicrobial chemotherapeutic chemicals, and antibiotics. Finally we will learn ways we are currently able to - or potentially in the future will be able to - improve or restore the body's immune responses through such techniques as immunization, adoptive immunotherapy, or immune modulation.
D. Relationship between the Human Microbiome (def) and Human Health
The complex mutually beneficial symbiotic relationship between humans and their natural microbes is critical to good health. It is now recognized that the millions of genes associated with the normal flora or microbiota of the human body -especially in the intestinal tract - aid in the digestion of many foods, the regulation of multiple host metabolic pathways, and the regulation the body's immune defenses. Click here for more information.
By the end of the course, all of these factors should fit together nicely to give you a good understanding of the "Big Picture of Infectious Disease."