As recently as 1998, the Colorado Department of Public Health and Environment was notified of a case of cholera in a seventy-three-yearold woman who had never traveled out of state. On September 19, the patient and eleven family members ate blue crabs that had been harvested along the Gulf Coast, precooked, and commercially distributed by a Louisiana company. Two days after the meal, the patient developed profuse watery diarrhea and nausea, and was hospitalized. Her stool culture was positive for Vibrio cholera.
PS, like its more famous vibrio relative, very rarely causes disease in the United States. Initially it was lumped with the vibrios, but over time doctors learned that PS was biochemically distinct from the true vibrios, even though there are similarities between the two bacteria.
One survey conducted by the CDC in Atlanta detected only thirtyone cases of PS in a one-year period in the entire United States. Some investigators feel that it is more common than that but some cases may go undiagnosed, which certainly might have happened with Katie Wolz had Dr. Ramsey not ordered the culture in the first place. The CDC group found that PS infections in the country are associated with eating undercooked shellfish or recent travel to areas with warmer climates, especially Mexico and the Caribbean.
A Canadian study arrived at similar conclusions. Like their American counterparts, these researchers found that many of their patients had traveled to tropical locales. A significant minority had never left British Columbia, however; most of those patients had eaten raw shellfish, mostly oysters. This link with eating undercooked shellfish, especially oysters, is also seen in patients with domestically acquired cholera. Most of the patients in both of these studies suffered from diarrhea, severe abdominal cramping, and fever. Some had gastrointestinal bleeding as well. In both studies, the largest that exist, nearly all of the patients with PS had either traveled abroad or eaten undercooked shellfish.
A group of Japanese investigators looked for PS in many different environments in and around Tokyo. Not only did they find PS in an occasional patient with gastroenteritis, but they were also able to culture the organism from 4 percent of dogs and 10 percent of cats. They also found the bug in 10 to 12 percent of samples of river water and sludge from riverbanks in the Tokyo area. This link with animals extends beyond dogs and cats. The bacterium has been found in freshwater fish, poultry, cows, pigs, even snakes.
And snakes from Japan are not the only ones to harbor the bacterium. One such serpentine example occurred in the case of an American man, a twenty-one-year-old employee in the animal research division at the National Zoo in Washington who had been caring for a boa constrictor that was ill with mouth-rot disease. The snake died, and the employee helped perform the autopsy. During the procedure, he wore a gown and gloves. About twenty hours later, on July 15, 1976, he developed nausea, vomiting, chills, profuse watery diarrhea, severe abdominal cramps, and low-grade fever. He was sick enough to go the emergency room at Georgetown University Hospital. He had a temperature of 100.4 degrees Fahrenheit and a fast pulse and showed signs of dehydration. The treating doctors sent off a stool culture.
When the man was still sick five days later, he returned to the hospital. The stool culture that had been taken on the first visit was now growing PS. Cultures from the snake obtained both before its death and at autopsy were also positive for organisms suggestive of PS. The man was treated with antibiotics for a week and recovered. In fact, most healthy adults with PS infections experience relatively mild symptoms that resolve without treatment. Others, however, like the zoo employee, need antibiotics and some are sufficiently ill to require hospitalization.
Most PS infections in humans involve the gastrointestinal tract, but the bacteria have also caused infections of the skin, joints, gallbladder, and bloodstream. On rare occasions, it can cause meningitis. In 1983, a three-day-old infant was diagnosed with meningitis. The pregnancy and delivery had gone without a hitch, but on day two of its life the child rapidly became blue and had diffuse contractures of his tiny muscles. He was given antibiotics and transferred to a pediatric ICU early the next day. On admission to the ICU, he had a cardiac arrest, but was resuscitated. A spinal tap revealed meningitis and PS was cultured from the spinal fluid and the bloodstream. At age four and a half days, he died. The precise source of the PS was never found. Although this case is exceptionally rare, it does show that PS can be a very dangerous bug.
Because PS infection is not a reportable disease in Missouri (or in most other states either), Tippen was not officially required to pursue the matter any further. “But it piqued my interest,” she explained, “so I decided to investigate anyway. I phoned Mrs. Wolz to get some background information.”
“Sue Tippen called me at work one day,” recalls Kathy Wolz. “She asked me if we had been out of the country and I laughed. With my schedule, we hardly go anywhere. Then we talked about other potential sources of Katie’s infection. We had visited a local swimming spot, Kentucky Lake, on July Fourth weekend, but the weather hadn’t been good, and Katie had barely been in the water, just splashed around some. We swam at another private lake in the next county around the same time, but I didn’t think Katie had drank any of the water or got any in her mouth, although I couldn’t be completely sure.”
After the first salvo of questions failed to provide much in the way of clues, Tippen then followed with a whole array of others. In her mind, she was trying to track down the source of the odd bacteria. Was it in the water? In the environment? The food? She pursued the investigation in several directions. She learned that the child drank only municipal water, and since no other cases had been reported in the area, that seemed an extremely unlikely source. She learned that the family’s only pet was a cocker spaniel named Maverick, and Maverick was perfectly healthy. Then they discussed food. Of course it came as no surprise that neither oysters nor other undercooked shellfish (or any other suspicious food) had been on the toddler’s menu. When Tippen found out that Katie attended a day care center, which seemed like a definite lead, she decided to investigate the site in person. “The director of the facility was not at all happy,” recalls Mrs. Wolz, who made that phone call. But as is usually the case in such situations, the director cooperated fully.
“My records indicate that I visited the day care center on August 12,” recalls Tippen, looking through her case file. “I spoke with several of the day care personnel. I found a clean, church-run facility with about a hundred children enrolled. In looking for any possible source of the PS, I did note that some guinea pigs were kept in a room where the older children congregated. But there were no animals in the infant room, where Katie and about ten other youngsters played. Furthermore, none of those other children at the facility were sick with similar illnesses as Katie’s.”
If the gastroenteritis had developed at the day care center, then it would be expected that there would be more than one case, and Katie was the only child who was ill. But Tippen learned about one other interesting fact on her site visit that day. There was a second connection between Katie and the day care center. One of the employees, a twentyyear-old named Marci Mann, babysat for Katie each Tuesday evening. Normally she would take care of Katie at the Wolz home. But occasionally, for some scheduling reason or another, Marci would bring Katie to her apartment. Tippen casually inquired about any animals at Marci’s place and learned that yes, Marci and her husband, Kevin, did keep several pets—a cat, and an aquarium stocked with five piranhas!
“We bought them from a tropical fish store in St. Louis, and we feed them minnows,” said Marci.
With this, Tippen felt a pulse of excitement rush through her body. She knew that piranhas were the infamous flesh-eating fish from the Amazon River basin in South America—distinctly tropical. She also knew that other scientists had isolated PS from fish tanks. In one British study done a year before, investigators took samples from one hundred fish tanks in six pet shops in the Cardiff area. A full 100 percent of the aquariums contained some kind of pathological bacteria. Salmonella
species were found in only eight of the tanks, but Aeromonas species (a bacterium closely related to PS), was found in ninety-eight of the tanks. And PS was found in one.
So the connection with an aquarium and tropical fish was quite possibly the missing link that Sue Tippen had been searching for.
Yet there were problems with the piranha theory from the start. First, the fish were in excellent health, although Tippen knew that this was frequently the case with diseases carried by animals and transmitted to humans. A bigger difficulty was that Marci and her husband kept the aquarium on a high shelf, and it also had a sturdy, tight-fitting cover over it. Toddlers are notorious for their Houdini-like skills, but there simply was no way that Katie could have gotten into the fish tank. Although Tippen felt sure that the piranhas had to be involved, she couldn’t see how, and the investigation seemed to come to a dead end.
But not for long.
“A couple of weeks later,” said Mrs. Wolz, “on a Tuesday evening when I entered Marci’s apartment to pick up Katie, I noticed something curious. Marci had just gotten Katie out of the bathtub. What struck me had nothing to do with Marci or Katie, but Marci’s husband. Kevin was feeding the fish. Because the subject of fish had come up in our conversations with Sue Tippen, Marci and I started talking about them. I hadn’t even known that they kept fish. I remember saying to her, ‘there’s no way Katie could get up there.’ Then Kevin began to clean the tank, and it was clear he was about to dump some of the water into the tub. The aquarium has a filter, but every so often, they would dump the water into the tub. That was because they live on a second-floor apartment, and the tub was the logical place to dump it. It still didn’t ring any bells.
“Then all of a sudden, it just clicked. Marci and I looked at each other and said at the same time, ‘the bathtub!’ Katie loves to drink water from the tub,” Mrs. Wolz explained. “She especially likes to suck on the wet wash cloth; we always joke about it.”
They quickly notified Sue Tippen, who, armed with this new fact, sent some sample bottles to Marci, who filled them with water from the fish tank. On August 23, she forwarded the water specimens to the state lab in Jefferson City to be analyzed for PS.
Fish can transmit several diseases to humans, mainly when eaten as food. Sushi is associated with various parasites, especially a tiny round worm that causes abdominal pain and diarrhea, a disorder called anisakiasis. Sometimes the pain is severe, and it has been misdiagnosed as a stomach ulcer or appendicitis. The fish tapeworm can also be transmitted by eating fish; years ago, this was not uncommon in Jewish grandmothers from New York as they tasted their gefilte fish before it was fully prepared. Far rarer is contracting botulism from eating fish. Toxins from fish can lead to scombroid and ciguatera poisoning and paralytic fish poisoning.
Handling fish can also lead to infections. There is a form of skin infection (cellulitis) that is due to a bacterium with another hard-topronounce name, Erysipelothrix. It’s important for doctors to consider this somewhat unusual cause since it responds to different antibiotics than are usually used for cellulitis. Certain vibrio species can also cause a severe cellulitis, including one called Vibrio vulnificus. This bug is generally spread via contact on abraded skin. The skin infection that results is associated with huge blisters that can cause the skin to slough off. It is especially severe in immunocompromised patients or those with liver disease, where it can sometimes lead to severe sepsis and death. These vibrio infections are most commonly associated with uncooked or raw shellfish, leading some to suggest that immunocompromised individuals should be very cautious when eating oysters and the like.
But can people get infections from the fish or the water in an aquarium? The answer is a resounding yes, although it does not happen very often. In the United States more than 20 million households have aquariums. Each year, approximately 600 million pet fish are sold in this country. These fish mostly come from Southeast Asia and South America. In spite of these enormous numbers, no major outbreaks of human disease from diseased aquarium fish have ever been reported.
One type of infection that people can get from their aquariums is called aquarium finger, swimming pool granuloma, or fish tuberculosis. The bacteria responsible are Mycobacterium marinum, which is closely related to the one that causes human tuberculosis. This infection can be acquired from swimming pools or aquariums, and from handling fish. Because the bacterium is more active at lower temperatures, it usually causes a skin infection characterized by exuberant growth of tissue called a granuloma.
The most frequent sign is a slowly developing nodule on the skin. Because the organism is suited to the temperature of the fish and not humans, it usually affects cooler parts of the body, such as a finger, hand, or arm. Later the nodule can enlarge and ulcerate. Nearby lymph nodes swell. Although these lesions may heal spontaneously or with special antibiotics, sometimes the bug can invade the joints and bones. As is the case with the vibrios, Mycobacterium marinum can be very severe in immunocompromised patients.
And of course there are the Aeromonas and Plesiomonas species. These organisms usually cause gastroenteritis, but both can lead to infection of the skin and other deeper tissues.
Why would a babysitter bathe a child before returning her to the parents?
“That may seem odd,” says Mrs. Wolz, “but I have a really bad allergy to cats, and Marci keeps cats in the apartment too. That’s why Marci generally sat for Katie at our house, but periodically, she’d take care of her at her apartment. On those occasions, I’d send a second outfit with Katie. Before I came to pick her up, Marci would bathe her and then dress her in the fresh clothes. The times we didn’t do that, my nose would close right up because of the cat dander.”
Two days later, the result from the piranha tank water was available: positive for PS. Tippen speculates that the dirty piranha water must have been emptied into the tub on one occasion just before Katie’s bath. Some of the bacteria would have still been on the wet surface of the tub when Marci filled it up for Katie’s bath. When Katie put the washcloth in her mouth, the PS got into her gastrointestinal tract. This was the last link in the chain of events that explained the strange case of Katie Wolz.
It was not the last step the epidemiologists took, however. The Missouri Department of Health launched an investigation to determine how commonly fish tanks were contaminated with PS. Public health agents sampled water from eighteen random aquariums at a number of pet shops and private homes across the state (including at least two tanks from each of Missouri’s six regional health districts). To their surprise, they were able to isolate PS in four of the tanks, or 22 percent. Three different pet shops had water that tested positive. None of the fish in those tanks were sick, nor were any of the employees in the three pet shops that had positive results. To prevent disease in the employees, the Department of Health simply recommended that the employees wash their hands after contact with the aquarium water or the fish.
Marci and Kevin continued to keep piranhas, and Marci continued to care for little Katie. The solution to that problem also proved remarkably simple. Marci and Kevin continue to empty their fish tank in the tub, but they wash the tub with bleach afterward.
Katie recovered completely. Dr. Ramsey obtained two sets of followup surveillance cultures; both were negative, proving that Katie had completely eradicated the unusual bacteria from her body. She has remained well ever since.
4 Rubbed the Wrong Way
“We had recently returned from California when it all started,” says Josephine Limone, thinking back to June 1992, when she got sick. “My husband Alfonso is a dentist, and we had just gone to a dental convention in Palm Springs. Several weeks after we returned, I remember that my underarms got very sore, first the left side I think and then the right. It was especially sore when I moved my arms. I took the subway to work and when I reached up to grab the handrail on the train, it really hurt.”
Limone, an attractive woman with shoulder-length dark brown hair, was twenty-five at the
time. She and Alfonso lived in midtown Manhattan, where she worked as an assistant administrator for the clinical laboratory at Mount Sinai Medical Center. “The next thing I noticed was swelling under my arms; it felt like marbles. Alfonso took a look and said they were swollen lymph glands. I was actually going to go to my gynecologist, because the location of one of them was closer to the breast tissue. That had me a little worried. The possibility of breast cancer did cross my mind.”
But the next day, as she was dressing for work, Limone detected the strangest symptom of all—small blemishes had appeared on various parts of her body. “At first, I thought it was just acne,” she recalls, “but they were in unusual locations: on my stomach, on my shins, one on my knee.” She applied witch hazel to the pimples, hoping that they would dry up in a day or so. But a couple of days later they still had not cleared up, and then she began experiencing dull headaches and a low-grade fever. She knew it was time to see a doctor.
“I asked Dr. Neville Coleman, the medical director of the lab where I worked at the time, to take a look at the blemishes,” Limone recalls. “He knew that I’d had chicken pox about a year before, and thought it might be a recurrence.” So Coleman called to speak to Edward J. Bottone, Ph.D., a professor of medicine and microbiology at Mount Sinai. The two doctors briefly discussed the case, and Coleman sent Josephine up to Bottone’s office for a formal consultation.
The Deadly Dinner Party: and Other Medical Detective Stories Page 6
