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The Relationship of Public Health to Urban Ecology
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by Angela Morrow
University of Northern Colorado
Greeley, Colorado
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| | Now that the community is an entire world, it watches, and squirms, as plague strikes Surat, Ebola hits Kitwit, tuberculosis overwhelms a Siberian prison, and HIV vanquishes a generation of Africans. The (world) community grows anxious. Though it empathizes, it fears that what is "over there" could come "here."
-- From Betrayal of Trust: The Collapse of Global Public Heath by Laurie Garrett (2000)
Microorganisms and Globalization
Listening to the evening news or reading the newspaper and news magazines has become almost a scary thing to do. SARS in the east and its potential spread to the United States and five deaths from West Nile disease in Colorado by August 2003 are but two examples of recent headline stories. Information and misinformation abound through the media; however, the underlying discussion is the proliferation of microorganisms and the globalization of our world. Typical citizens can expect to be faced with more microbial crises due to increased urbanization, which is predicted to continue throughout the century. This complicates the field of public health and necessitates the better training of citizens with regards to the area of microbiology.
Lifestyles of American citizens have undergone tremendous changes since the end of World War II. The reasons for these changes are varied and numerous, but include the large number of families in which both adults work outside the home. This has necessitated increases in day care services, cleaning services, personal care services, and a variety of food services. Food services have expanded to encompass grocery stores with delis, salad bars, hot meals, prepared fruit and vegetable trays, precut and washed fruit, vegetables, and salad greens, and even online services. In 1960, only a few prepared meals such as frozen dinners, pizza, and pot pies could be purchased in the freezer case, but now the range includes everything from gourmet items to specially prepared diet foods. These meals are not just being purchased to be heated in an oven and consumed at home, but many will find their way to lunch boxes and microwaves in the workplace. Meals can be purchased through carry-out, drive through, delivery, or even online service.
The restaurant trade has also increased, and the variety of foods/restaurants available even in fairly small towns is enormous. Pre-WWII, a few families might have employed a cook or housekeeper. In this era of more family members in the workplace, there are fewer families employing person(s) in this capacity. Rather, a family might use a cleaning company that services a number of households during a week and might also employ a cook who prepares meals for a week and leaves them in the family's refrigerator or freezer. This expansion in food services has not been without problems. As a result, we have seen an increase in food-borne illness, as recorded by the Center for Disease Control (CDC), despite better methods of food preservation and storage. (See figure 1 for some current examples.) The FDA has the responsibility for insuring the safety of over 20 percent of the American economy, with that percent growing each year. According to Dr. Mark McClellan, FDA commissioner, "While our knowledge of nutrition and how foods may influence our health is greater than ever, we are facing hundreds of billions of dollars in preventable medical cost... that can be prevented through better consumer choices and food products." The U.S. faces "threats from potentially unsafe medications and food that are based on increasingly complex production processes."
Figure 1: Examples of USDA Recalls from April 2003 to August 2003
| Food |
Bacteria |
Bacteria |
| Cut cantaloupe and honeydew |
Listeria |
Portland, Oregon |
| Ground cumin |
Salmonella |
U.S. distribution |
| Potato salad |
Listeria |
New York delicatessen |
| Bologna |
Listeria |
U.S. distribution |
| Beef products |
Insanitary conditions in processing |
Michigan |
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New Environments Rich in Bacteria
Personal care services at the end of WWII typically included beauty parlors and barbershops. These establishments might have performed manicures and occasional pedicures along with hair care and shaving, in the case of barbershops. Home care for these services was usually rendered by a family member or perhaps a personal maid/valet. Today a typical hair care facility might offer both male and female hair care and perform manicure and pedicure services that include the use of many types of artificial nail applications, skin treatments, massages, and other spa-type services. For every service that is performed, the risk of additional reservoirs, vectors, contamination, and transmission of pathogens increases. Outbreaks of several species of Mycobacterium have been reported in a wide variety of settings such as indoor swimming pools, hot tubs, water-damaged buildings, and the metal working industry. The common thread for the spread of these infections is water and aerosol exposure. (Certainly students would have benefited from this knowledge on the 2000 APES free-response question concerning the sick building syndrome.) In recreational water situations, diarrhea (from such bacteria as E. coli and Shigella, protozoans such as Giardia and Entamoeba, plus various viruses) has been on the rise since the mid-1980s. One reason is more germs that are increasingly resistant to chlorine used to disinfect the water (CDC 2003). The bacteria Legionella (Legionnaire's disease) has been found in hot water tanks, hot water propeller heads and faucets, and whirlpool spas (CCOHS 2003).
The local YMCA or gym has in large part been replaced by full-service health clubs, which might offer a number of fitness-type classes, cardiovascular exercise equipment, and weight-lifting equipment as well as any number of spa services. As with the personal care services, the risk of pathogen transmission has also greatly increased. Just the increase in the numbers of patrons would insure that risk.
The aforementioned human services by no means exhaust the list of similar services offered presently or to be offered in the future, but it does demonstrate the present and potential risk of disease transmission through the use of various human services. In addition to changes in human services, the expansion of the boundaries of commerce or what might be referred to as the globalization of commerce has led to additional risk from pathogens that "hitchhike" their way to new hosts (e.g., SARS). The concept that the health of our nation depends on the good health of its population is not just a pious statement but has become an epidemiological fact.
However, terror over microorganisms by the general populace is as ignorant as believing all insects are bad. Life as we know it would cease without microbes. Foods we enjoy such as yogurt, cheeses, breads, and fermented alcoholic beverages would not exist. We would have a difficult time with our gastro-intestinal tract without the microbial flora. Our discomfort even at the conclusion of a bout with an intestinal bug is a testimony to that fact. Although usually ignored, the decomposition action of microorganisms is essential to the cycling of nutrients. I continually point out to students how inconvenient it would be to continually trip over every dead tree or to try to find a place to stack dead animals, including us! Although that certainly is a flippant statement, it does bring home the concept that microorganisms have an important function in the so-called "circle of life."
People Play an Active Role
The typical citizen's lack of education in the field of microbiology has led to the overuse of antibiotics to the point that antibiotic-resistant bacteria are abundant. Daily, individuals try to soap, spray, and wipe their normal microbial flora off their bodies only to have it be replaced by more dangerous organisms, such as the removal of the normal Staphylococcus found on the skin being replaced by the opportunist and resistant bacteria Pseudomonas. Experiments done with germ-free animals demonstrated that those animals were sickened by a dose of 10 Salmonella bacteria cells, whereas in normal animals the dosage needed for infection is 106 cells. Billions of dollars are wasted on ineffectual or even hazardous products.
On the 2002 APES Exam, students were asked to consider how El Nino would affect disease transmission. Although certainly some of the traditional answers to this question would be appropriate (e.g., flooding and pooled water provide mosquito breeding grounds, and flooding would allow for contamination of ground water), the intense concentration of the population into urban settings adds a new dimension to disease transmission. It also heightens the importance of asking such questions of our students. Any concentration of people will increase the risk of disease transmission, and environmental stresses such as an El Nino event will elevate these risks.
Urbanization and globalization of the world's populations continues to be a trend. Increasing populations in confined areas will increase the number of pathogen reservoirs and increase the risk of contracting a communicable disease. These facts make it important to discuss with students elements of disease transmission and the role of microorganisms. As for the "test," who knows? Maybe the next APES Exam will have a question concerning the automobile plant in Fremont in which Legionnaire's disease has broken out.
More information and pictures are available on the CDC, USDA, and FDA Web sites.
Reference
Books
Garrett, Laurie. 2000. Betrayal of Trust: The Collapse of Global Public Health. New York: Hyperion Press.
Talaro, K. P., and A. Talaro. 2002. Foundations in Microbiology, 4th ed. McGraw-Hill International Edition.
Web Sites
Canadian Centre for Occupational Health and Safety Resource (CCOHS).
 Canadian Centre for Occupational Health and Safety
Centers for Disease Control and Prevention (CDC). 2003.
Centers for Disease Control and Prevention
Food Safety Inspection Service (USDA). 2003.
Food Safety Inspection Service (USDA)
U.S. Food and Drug Administration (FDA). 2003.
See Mark McClellan's Mission Statement.
FDA
Dr. Angela C. Morrow is a research associate at the University of Northern Colorado. She holds a doctorate in the areas of botany and microbiology and is currently investigating wound response in woody plants at the ultrastructural level and better ways to pulp wood. She has been involved with APES since the course's beginnings. In addition to participating in the exam Reading and this lab project, Dr. Morrow is a workshop consultant for APES.
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