Over the past five years, Sarah Pierce has suffered repeated kidney failure, spent three years on dialysis, had the plasma in her blood replaced twice, and lost a fiance, friends and a job -- all because of something she ate.
Pierce, now 30, was infected with a toxic strain of bacteria, E. coli O157:H7, that can be spread through undercooked meat or raw produce. Today, she has a healthy kidney donated by her brother, a full-time job and a husband. But the medicines she takes to keep her body from rejecting her replacement kidney carry a high risk of causing birth defects, so she has ruled out pregnancy.
"I would have liked to have had children," she said.
Pierce belongs to a small subset of people who develop long-term health problems from food poisoning. Their ranks are growing. Over the past decade, as medical experts have sought out the source of certain chronic illnesses, they have increasingly found links to episodes of food poisoning, sometimes many years beforehand, according to the Centers for Disease Control and Prevention.
Campylobacter, a bacterium associated with raw chicken, is now recognized as a leading cause of the sudden acute paralysis known as Guillain-Barré syndrome. Certain strains of salmonella, the bacterium involved in the recent outbreak in Mexican raw jalapeño and serrano peppers, can cause arthritis. And E. coli O157:H7, a strain of an otherwise harmless bacterium that lives in animal intestines, can release toxins that cause hemolytic uremic syndrome, or HUS, a kidney disorder that in 25 to 50 percent of cases leads to kidney failure, high blood pressure and other problems as much as 10 years later.
This list is just the beginning of the many health problems some people are now attributing to food-borne infections.
"What the classical medical literature says and what we've seen is not the same," said Donna Rosenbaum, executive director of Safe Tables Our Priority, or STOP, a nonprofit that represents people who have suffered serious food-borne illness.
The CDC estimates there are 76 million cases of food-borne disease in the United States annually. The vast majority of people experience it only as an unpleasant bout of diarrhea or abdominal pain, though an estimated 5,000 to 9,000 Americans die each year from food poisoning. A handful of pathogens are responsible for more than 90 percent of those fatalities: salmonella, listeria, toxoplasma, noroviruses, campylobacter and E. coli. Those most susceptible to infection are small children, the elderly and people with compromised immune systems.
Until recently, doctors were focused on the acute phase of food-borne infections, but since the 1990s, there has been "a more gradual recognition that some of the pathogens do have long-term [effects]," said Marguerite Neill, an infectious-disease specialist who teaches at Brown University. "We're already on the right track in terms of [saying] food-borne illness is more than diarrhea and may end up with long-term [illnesses]." Some doctors are now wondering, for example, whether food-borne infections trigger irritable bowel syndrome and colitis, said Andrew Pavia, an infectious-disease expert at the University of Utah.
However, long-term health effects of food-borne infections are hard to study, for a variety of reasons. First, it is tough to prove a link between some of these illnesses and later chronic conditions such as arthritis. Second, despite annual outbreaks across the nation, the subject hasn't attracted much public attention or funding, Neill said. Also, federal health-care privacy laws make it difficult for researchers to approach anyone who is not in their direct care.
To get around the last of these problems, STOP is setting up a national registry of victims of food-borne disease who would be willing to participate in longitudinal studies. The registry could help researchers determine, for instance, how frequently food-borne infection leads to chronic health problems and what role factors such as genetics play in who develops them.
A Case Study
Researchers and clinicians face unique challenges when studying the long-term effects of HUS. The first outbreak associated with E. coli in the United States was in the 1980s. Many of the earliest victims are only now entering their childbearing years.
Also, the number of HUS cases is small. Only about 5 to 10 percent of the 73,000 people each year who get sick from E. coli develop HUS.
The impact of HUS, however, is great. In the acute phase, microscopic blood clots may form in the kidney, leading to kidney failure, Neill said. Sometimes the kidney can be rescued with temporary dialysis. Less commonly, these blood clots form in organs such as the brain and cause stroke or seizure. There may be permanent damage to the kidney.
According to a long-term study of 157 HUS victims co-written by Pavia in 1994, more than half developed kidney problems seven or more years after the initial illness.
These people face a lifetime of medical treatment. "Anyone with HUS will be monitored for the rest of their lives. If the acute course was severe enough, the risk of long-term kidney complications, including end-stage renal disease and kidney transplant, is quite high. The future medical cost alone can then be in the millions," said William Marler, a Seattle lawyer who sues retailers and food companies on behalf of food poisoning victims.
That is the scenario Elizabeth Armstrong faces. Her two daughters got sick after eating bagged baby spinach in 2006. Her older daughter, Isabella, who was 4 at the time, survived with no apparent health problems. But her younger daughter, Ashley, who was 2 at the time, developed HUS. She has only 10 percent kidney function and will likely need more than one kidney transplant in her lifetime, including one before she is an adult. Also, when she becomes an adult, Ashley may face the same dilemma that Sarah Pierce did: deciding whether bearing a child is worth the risk.
There may be a way to prevent the worst HUS cases and their consequences. Doctors in Washington state have found that it is important to hydrate a patient if they even suspect an E. coli infection. Doing so helps reduce the extent of injury to the kidneys. More research needs to be done to identify other effective interventions, said Phillip Tarr, an HUS expert at Washington University School of Medicine in St. Louis.
"There is a lot we don't know yet," Tarr said.