Microbes and Disease

Pathogens Many microbes are beneficial Decomposers, oxygen, normal flora However, a small % can cause disease (<1%) Organisms that cause disease are called pathogens. Pathogens = germs

Pathogens All viruses are pathogens A few bacteria, protists, and fungi can be pathogenic as well. Pathogens cause disease in one of two ways: Invade another organism to get the nutrients and/or reproductive machinery Produce toxins

Why Microbes Make Excellent Pathogens: They are microscopic. You don’t know you are sick until you develop symptoms, and by that time the microbes have had time to establish themselves in the organism. They multiply rapidly. They are always changing and evolving.

Infectious Disease Diseases caused by pathogens are called infectious diseases. Infectious diseases have different abilities to spread. A sick person who is capable of spreading the disease is contagious. A person who could potentially get the disease is said to be susceptible. People who are not susceptible are said to be immune.

Spread of Pathogens Diseases spread by one of three methods: Host-to-host transmission From one infected person directly to another Vectors A vector is an organism that carries a pathogen and passes it on to another organism without ever becoming sick itself. such as a mosquito, flea, rat, tick, etc. Environmental sources Food, water, and other objects

Spread of Disease Epidemiology is the study of the spread and control of disease in a population. An epidemic is an outbreak of a disease that affects a disproportionately large number of individuals within a population, community or region at the same time (example-typhoid). Pandemic is an epidemic of an infectious disease that is spreading through human populations across a large region, continent or even worldwide (examples smallpox, tuberculosis, flu of 2009)

Spread of Disease Epidemiologists study factors that influence the spread of disease: Overcrowding Lack of sanitation Contaminated drinking water Climate (warm, moist climates tend to have lots of mosquitos which are vectors for many infectious diseases.)

Prevention By controlling the growth of infection, we can control the risk of infection. To disinfect means to eliminate most harmful microorganisms (not including their spores) from surfaces or objects and to inactivate viruses To sterilize means to kill ALL microbes - whether harmful or not - and their spores present on a surface or object. To inhibit means to prevent microbes from reproducing.

Prevention Methods for Controlling the Growth of Microbes: Heat Radiation Filtration Antiseptics Chemicals that will control the growth of microbes without harming other living tissue Disinfectants Chemicals that will kill microbes on surfaces and objects

Treatment When microbes get into your body, your immune system searches for, recognizes, and destroys most pathogens. However, sometimes your body needs help. Antimicrobial drugs are designed to kill or stop the growth of microbes living in a host without too much damage to the host. Antibiotics are a naturally occurring chemicals that kill microbes in an organism. Scientist have also designed artificial antimicrobial drugs.

Prevention and Treatment Improvements in public health depend upon state-of-the-art biomedical research to explain how microbes cause infectious diseases in both plants and animals. To analyze data, scientists use various techniques and strategies including computer modeling, cell culture, animal models, and clinical trials in humans. Safe handling and hygiene as well as various antimicrobial chemicals can be used to reduce the risk of and the treatment of these infections. Industrial microbiology involves quality control in preventing growth and contamination of products to make sure they are safe.