Lec37_Pathogens - Lecture 37: Pathogens INTRODUCTION...

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ecture 37: Pathogens Lecture 37: Pathogens
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athogens are disease roducing organisms INTRODUCTION Pathogens are disease-producing organisms. They enter the human body either through the skin or with drinking water It is difficult to measure the concentrations of individual pathogens Hence Indicator Organisms are used - These are groups of organinsms that are easy to measure he idea is that if indicator organisms are present then pathogens may also be present The idea is that if indicator organisms are present, then pathogens may also be present. Category Description Species Bacteria Microscopic, Vibrio cholerae unicellular Salmonella etc. E. coli Viruses A large group of bmicroscopic Hepatitis A submicroscopic infectious agents Entero viruses Protozoa Unicellular animals Reproduce by fission Giardia Cryptosporidium Naegleria fowleri Helminths (Intestinal worms) Worms and wormlike parasites nematodes Algae Non-vascular plants Some produce toxins Anabaena flos-aquae
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Indicator Bacteria • Total Coliform (TC): A large group of rod-shaped bacteria. E. Coli and aerobacter aerogenes are some well-known members of this group. They exist in both polluted and unpolluted soils. • Fecal Coliform (FC): A sub-group of TC that come from the intestines of warm- blooded animals. They do not include soil organisms and hence preferable to TC. • Fecal Streptococci (FS): These include several groups of streptococci that originate from humans and domesticated animals (e.g., horses). Attempts to use FC/FS ratios to determine contamination sources (human versus non-human) have not been very successful because: 1. Since bacteria die-off at different rates, sampling needs to occur soon after deposition 2. Difficult to distinguish fecal streptococci in wastes from streptococci that are naturally present in soils and water
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E. coli They are necessary for the proper digestion of food and are part of the intestinal flora. Its presence in groundwater is a common indicator of fecal contamination oli color E. coli in color
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Drinking Water The assurance of safe drinking water in the U.S. continues to be a challenge as a result of emerging and newly recognized contaminants, more sensitive and specific detection methods, better investigations, and more public awareness. The occurrence and control of microbial pathogens, including viruses and parasites, have been of particular interest.
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This note was uploaded on 01/20/2011 for the course ENE 804 taught by Professor Hashsham,s during the Spring '08 term at Michigan State University.

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Lec37_Pathogens - Lecture 37: Pathogens INTRODUCTION...

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