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4 COWS, CATS, AND PURE COUNTRY WATER

E. COLI AND OTHER WATERBORNE BACTERIAL INFECTIONS

DRINKING BOTTLED water every day is like using a toilet bowl brush to clean your teeth, driving a snowmobile for recreation, or using an all-terrain vehicle in the city. All these items have important uses, but in most parts of the world none of them should be part of everyday life. When they are used outside of the circumstance for which they are designed, they are, for the most part, destructive and dysfunctional. Bottled water is for emergencies and should be saved for them.

Mostly, I dislike bottled water because it represents an unwarranted and pervasive anxiety in Western societies. Bottled water purports to solve an individual problem—fear of illness—by contributing unnecessarily to big public health problems—large-scale water and energy shortages and under-funded public water systems. I hate the idea that someone can suck an increasingly scarce public good out of the ground and then use scarce energy resources to package it and sell it back to the public. This process fosters an obsession with personal health, even as it puts the health of our children in jeopardy by undermining the health of the ecosystems that provide the basis for all life. The money spent on bottled water would be better spent on improving public water systems.

Bottled water may or may not be safer than tap water. The jury is out on that. Because any disease outbreaks caused by bottled water would be widely dispersed and not likely linked by individuals or physicians to that plastic-wrapped water on the counter, they would not very likely be identified. Because most people see bottled water as a solution rather than a problem, there’s not much in the literature. In 1993, two babies were brought into a Wisconsin hospital having seizures; the seizures were caused by intoxication with low-sodium bottled water, the mother having apparently thought that bottled water was better for her babies than tap water. In 2000, the Centers for Disease Control and Prevention reported that it had detected a ten-state bottled-water-associated outbreak of salmonellosis through a special pattern-recognition program called the Salmonella Outbreak Detection Algorithm, or SODA for short. A report in the journal Emerging Infectious Diseases identified bottled water as one of the risk factors for Campylobacter infection in the United Kingdom.

I am not a fanatic about bottled water. It obviously makes sense in natural disasters, such as the sudden floods in Vancouver (probably related to global warming) in the fall of 2006. I used to carry water bottles onto airplanes, where the air is very dry, but since August 2006, this has become impossible. I don’t mind, as long as water is readily available on the plane. I occasionally carry bottled water in the car or on hikes. If I have bought a bottle of water, I always refill it from the tap, a practice that bottled water companies warn me against, as they suggest it might lead to contamination.

I often drink bottled carbonated water in parts of Africa, Asia, and Latin America, where public funding for clean water has been scarce (usually as the result of development or financial or trade programs instigated by financial institutions based in North America or Europe). I drink the carbonated stuff because the nonbubbly bottled water, in whatever country you live, is often no better than the water out of the tap. In most countries, however, including nominally Muslim countries, I prefer the beer (which I know uses a lot of water).

The bottled water industry thrives on a public fear of contaminated water, and I really don’t like any industry that thrives on fear, especially fear that I have contributed to, which, by teaching about food. and waterborne diseases, I probably have. If this chapter on waterborne disease drives you to drink bottled water rather than to advocate for better public water systems, then I have failed.

So let me start by confronting the fear.

In May 2000, the small rural town of Walkerton, Ontario (population about 5,000), hit the international headlines. I remember the day, because a friend called me into the common room at the Makerere University Guest House in Kampala, Uganda, to tell me that Canada was in the news. People were dying from drinking tap water.

It started with a few reports of cases of bloody diarrhea in nursing homes and schools and ended with more than 2,300 people sick. Twenty-seven people had to be hospitalized with hemolytic uremic syndrome, a rare disease involving the breakdown of red blood cells, blood in the urine, and kidney failure. At least six people died. Some of my best friends and colleagues (veterinarians and graduates of our epidemiology program at Guelph) led the public health investigations, so I got a variety of inside and outside stories. The outbreak led to one of the most thorough inquiries into a public health disaster in Canadian history.

The drinking water for a large part of the town had been contaminated with two organisms: vero-toxin producing E. coli, or VTEC (pronounced vee-tek) for short, and Campylobacter. The most common type of VTEC is also called O157:H7, the O referring to some proteins on the surface of its body, and the H to proteins on its tail. Other E. coli’s produce the same kind of toxin, but O157:H7 is the most famous. The toxin, also called shiga-toxin because it is the same one produced by Shigella, which causes bloody dysentery in travelers and people who live in poor neighborhoods, kills kidney cells from African green monkeys (vero cells). There must be a good reason that the laboratory people picked exactly those cells to test toxins in—some dislike of African green monkeys perhaps. The green monkeys wrought their revenge by inflicting a hemorrhagic illness called Marburg disease on some of the lab workers, but that is another story.

In one sense, the presence of these organisms in water systems in rural areas was not surprising. Our research group at Guelph had identified rural areas and areas with denser cattle populations that spread manure on farmland as having higher rates of E. coli-related infections than urban areas. We’d already had one tragic outbreak in Ontario related to a well-run farm, in 1986. It was a typical Ontario farm, with sixty-seven cows and calves, some chickens, and some pigs, all well cared for and clean, and seemed the perfect place to take your class of preschoolers. In April of that year, sixty-two preschool children and twelve supervising adults visited this farm. They played in the barn, petted the calves, pulled at the cows’ teats, and gathered a few eggs. For a break, they drank milk (right from the farmer’s tank!) and ate egg cookies (sliced hard-boiled eggs cleverly renamed to induce children to eat them). A good time was had by all.

Within the next two weeks, forty-two children and four adults came down with abdominal cramps and diarrhea. Three of the children ended up in hospital with hemolytic uremic syndrome. One of the children fell into a coma. All eventually recovered.

The public health investigators looked everywhere on the farm. Although they found only two calves carrying the organism, they decided that exposure to the unpasteurized milk was the most plausible explanation for what they saw. And yet the farm family, which drank that milk every day, was apparently healthy and not shedding V TEC. Since that time, VTEC had been found to live comfortably and usually without any harmful side effects in the intestines of many cattle, just about wherever cattle are raised, at least in industralized countries.

Campylobacter, particularly C. jejuni, the other organism found in the water at Walkerton, has been found in many of the same waterborne outbreaks as E. coli. Campylobacter is the bug of choice for cooks, college students, drinkers of raw milk, and, if the aforementioned study in the United Kingdom is to be believed, bottled-water drinkers.

Although reports of so-called intestinal flu involving curvaceous wiggling organisms in milk go back to 1946, the first major review of Campylobacter jejuni as a possible common cause of diarrhea in people only appeared in the scientific literature in 1977. Just about everywhere researchers have looked for it, they have found it; it is at home in most warm-blooded animals but seems to have a fondness for birds. Today most researchers consider it the most common cause of bacterial diarrhea in the United Kingdom and in North America.

Campylobacter does not grow very well in food, which is why it causes disease in those who handle raw food, such as cooks. College students, especially those who eat chicken and live with cats, were shown in one study to be a high-risk group. This is related to the “second weaning” phenomenon; those poor suckers are just learning how to cook and they discover that what looked easy when Mom and Dad did it actually requires some skill. Symptoms of the disease—diarrhea, abdominal pain, headache, fever, bloody stools, nausea, and sometimes vomiting— start up to a week after the offending meal and last a week. The reason some of these infections take so long to develop is that the bacteria make their way down to the large intestine before setting up shop, multiplying like mad, and making trouble. That’s also why you see actual blood in the stools of infected people; if the infection is higher up, in the small intestine, the blood is digested and you see black tarry stuff coming out.

Like Salmonella, Campylobacter doesn’t just cause immediate damage to the gut. Some victims get reactive arthritis I described in the section about salmonellosis. About one in a thousand of those infected with Campylobacter go on to develop a paralytic disease called Guillain-Barré syndrome.

Campylobacter grows best at about 108°F, which is quite warm. That is why it is often associated with birds, which have a higher internal temperature than us mammals. In one study in the United Kingdom, milk bottles that had been attacked by free-enterprising starlings at the doorstep were found to be a source of infection for people. The birds followed the milk delivery truck and then poked through the tops of the bottles for a fresh drink. Although Campylobacter grows best in birds, it has been isolated from river and sea water, mud, sewage, and sludge.

This disease appears to be most serious in Western peoples living under conditions of good hygiene. In many developing countries, it seems to be found almost as often in healthy people as in sick people. Clinically normal animals in all countries can carry the organism. In people in developing countries, and in farm animals in North America, the organism can be found with just about equal frequency in healthy and diarrheic individuals.

Although infection is common, disease, in adults at least, does not appear to be as common as would be expected, suggesting that immunity might be developed by continuous exposure. One study has shown that college students who visited a friend’s home farm got sick from drinking the milk, while the farm family remained cheerfully healthy. One of the costs, then, of protecting children from disease is that, as adults, they are more vulnerable. The alternative, however—to expose kids while young and let the strongest survive—is hardly tenable morally.

Overall, the presence of V TEC in cows and Campylobacter in a variety of animals didn’t explain the Walkerton outbreak. I visited the farm from which, allegedly, the offending organisms entered the city’s water system. It was run by a veterinarian just outside the town limits. It was no factory farm. Like the farm in the center of the 1986 tragedy, it was an idyllic place, with some corn and a few cows, the kind of place held up as a perfect example of all those who want a return to the simple life of small family farms. The farmer had in place a good Environmental Farm Plan, a program devised by Ontario farmers to assess how well they are managing the landscapes of which they are stewards.

There are a lot of bad things a person could say about feedlots and factory farms, and I would be one of the first to voice them, but the Walkerton outbreak cannot be laid at that door. The outbreak represented a failure to think systemically; it was a triumph of boundaries, blinders, governmental departmental silos, and small-mindedness. The farm was just outside city limits, so the ecologically important boundaries did not match the political decision-making boundaries. The contaminated well was located on low ground, apparently in a place that engineers had advised against but that made short-term economic sense. The provincial government was ideologically driven and reckless, typical of both communist and free enterprise governments the world over. It cut back on environmental programs, privatized laboratory testing, and downloaded responsibilities without paying attention to whether local officials were up to those responsibilities. The guy who was supposed to monitor water quality didn’t know anything about water quality, drank on the job, and fabricated data. Nobody seemed to be quite sure who was supposed to report to whom or who was ultimately responsible. Because of all the government cutbacks, no one was watching. The government seemed more concerned about building highways, encouraging the trucking industry, and dismissing the values of higher education than they were about public health.