ourENVIRONMENT

Can We Still Drink the Water?

People have considered their drinking water questionable for years now and over the last couple their suspicions have been realized. tainted water has become a civic nightmare that just won't go away....

Last year in a small town in Ontario Canada, the unthinkable occurred; people died from drinking tap water. The quality of drinking water has been an on going concern for decades, but most believe that, though not the best smelling or tasting, tap water is safe and most don’t hesitate to drink and cook with it. It was just this kind of trust that led to the death of a number of people in Walkerton Ontario Canada last year.

Submerged in political back-stroking, the cause has been volleyed back and forth and the blame has yet to rest firmly on the shoulders of any one. What was it that killed these people anyway? E. coli is short for Escherichia coli and is a type of bacteria commonly found in the intestines of animals and humans. There are four recognized classes of enterovirulent E. coli (collectively referred to as the EEC group) that cause gastroenteritis in humans. Among these is the enterohemorrhagic (EHEC) strain designated E. coli O157:H7, which is the dominant species found in feces. Normally E. coli serves a useful function in the body by suppressing the growth of harmful bacterial species, and by synthesizing appreciable amounts of vitamins, but a small minority of E. coli strains are capable of causing human illness.

This particular strain is a rare variety of that produces large quantities of one or more related, potent toxins that cause severe damage to the lining of the intestine resulting in hemorrhagic colitis. The illness is characterized by severe cramping (abdominal pain) and diarrhea which is initially watery but becomes grossly bloody. Occasionally vomiting occurs and fever is either low-grade or absent. The illness is usually self-limited and lasts for an average of 8 days. The Infective dose is unknown, but from a compilation of outbreak data, including the organism's ability to be passed person-to-person in the day-care setting and nursing homes, the dose may be not be that much. It’s this that has led citizens from neighboring towns to ostracize Walkerton residents, cancelling sporting events and shunning them when they come to town.

So how does E. coli get in our water? The presence of E. coli in water is a strong indication of recent sewage or animal waste contamination. Regardless of how up-to-date a community’s filtration system may be, when it rains on the manure covered pastures or there is flooding, E. coli is washed into creeks, rivers, streams, lakes, or seeps into the groundwater. And when these are used as sources of drinking water, and the water is not treated or inadequately treated, E. Coliis unknowingly consumed by humans. With the increasing number of factory farms, high concentration of animal waste is an ever growing threat. It was similar farm conditions which led to the now infamous “Mad Cow Disease” which ravaged a number of English towns. In that case animals were actually fed contaminate ani,mal parts and feces.

How did this strain of E. coli come to be? The true problem in detecting e. Coli is compounded by the simple fact that it is often found in water supplies and it’s difficult to determine the particular strain. In the case of E.coli O157:H7, a long-ago cell appears to have been infected with a bacterial virus. This particular virus had the ability to insert its own DNA into the bacteria's chromosome without harming the bacterium and to remain there. Now, every time this bacterial cell divided, the virus DNA, being now a part of the bacterial DNA, was passed on to every daughter cell and now we have the deadly E.coli strain, O157:H7.... This virus's genes contained information for the production of a toxin, called Shiga_like toxin (SLT), or is sometimes called, Vero toxin. Consequently, this strain of E.coli, and all of its progeny produce this toxin. The toxin is a protein which causes severe damage to intestinal epithelial cells (the cells that line the wall of the intestine). The damage is so severe that if we acquire this bacterial strain, not only do we lose water and salts but blood vessels are damaged. This condition is particularly dangerous to small children and may be lethal. Children are too small to tolerate much blood and fluid loss and it is for this reason that small children should not be allowed to become dehydrated, even in mild cases of diarrhea.

In some cases another syndrome is involved which is called hemolytic uremic syndrome (HUS), which is characterized by kidney failure and loss of red blood cells. Approximately 5% to 10% of children progress to this stage of disease _ which is very dangerous for them. In severe cases, the disease can cause permanent kidney damage. The presence of this bacterium can also be very dangerous to the elderly or infirm. There can be a combination of HUS and some other things which involve the blood system, which can be lethal to the elderly in 50% of the cases.

How does it spread? Infections spread by many food sources such as undercooked ground beef, unpasteurized milk and apple cider, ham, turkey, roast beef, sandwich meats, raw vegetables, cheese and contaminated water. Once someone has eaten contaminated food, the infection can be passed person-to-person, by hand-to-mouth contact. What do you do if you get sick? No matter when, if diarrhea occurs, always pay close attention to the symptoms. Look for the presence of fever, vomiting and diarrhea. Look for any signs of blood in the stool. If you see anything that worries you, call your physician immediately. don't worry about the possibility of being mistaken and perhaps looking "silly." The organism is difficult to identify [recommended method is to use a genetic probe associates with the toxins’ gene sequence(s).

How long does it take for any symptoms to appear? Well, the answer to this question is a tough one. There are many things which may influence the onset of symptoms for this particular disease. Symptoms may appear within hours or may appear only after several days. The following are some of the things which can influence the time it takes for symptoms to occur: (1) The actual number of organisms ingested; the higher the number ingested, the sooner the possibility for symptoms (the relatively greater concentration of toxin made). (2) The health status of the individual; the weaker or less healthy, the sooner the possibility for symptoms. (3) The individual's natural resistance to either (a) the growth of the organism within the intestine, or (b) the effect of the toxin itself.

Different people may respond differently. Usually, the disease is self-resolving (means that the disease clears "on its own") within about 8 days or so. How to stop the spread Wash hands thoroughly and frequently. Clean and sanitize counter-tops and utensils after contact with raw meat. Cook ground meat until it's no longer pink. Drink only pasteurized milk or cider. Don't handle food if suffering diarrhea. Drink water from a supply known to be safe. If you have a private water supply (well) it should be tested several times a year. Refrigerate or freeze meat as soon as possible after buying it and then thaw frozen meat in the refrigerator, not on the counter. Place cooked meat on clean plates. Don't re-use dishes that have been in contact with raw meat.

Who tests for E-coli? If you have your own well, it is up to you to do your own testing. There a number of labs that will conduct specific tests on your drinking water, detecting a variety of contaminants. In Ontario, at the municipal level, it is the local public utilities who are responsible for testing. Part of the defense of the Walkerton PUC is that they were unaware of their responsibilities as new legislation has recently passed the responsibility on to the municipalities.

Could this happen anywhere? Yes it could. The best measure of prevention is to boil all tap water and drink bottled water only. This of course becomes a problem in parts of the world where the cost of water is prohibitive and testing unrealistic. In the industrialized western world, we may be more at risk due to our innate trust of our surroundings. As the richest nations in the world, it’s hard for us to believe we can’t drink our water or breathe our air, but as we detect year after year, our resources are quickly becoming as tainted as those of the “developing nations”. Most obviously, our endangered water supply can be revitalized by disallowing the spread of animal waste on farm land and the further restriction of air borne contaminates. How realistic is that? Well, with an ever present population of meat eaters, farmers will continue to grow animals for consumption, creating tons of waste that has no where to go. Hence, the vicious circle...