More Than Just an Upset Stomach

An unfamiliar pathogen attacks unsuspecting passengers on a jetliner

By Claire Panosian Dunavan|Tuesday, July 01, 2003
RELATED TAGS: INFECTIOUS DISEASES

Not long after landing, an attendant on Flight 386 knew something was wrong. Between gurgles, pings, and cramps, her gut felt like a punching bag. She quickly disappeared into the lavatory.

Meanwhile, in a different part of town, a passenger from the same flight was also in distress. Her bowels were running like water. Suddenly it dawned on her: This intestinal bug was out of control.

In a third house in the sprawling metropolis, a 70-year-old man who had just flown 6,000 miles to visit his family checked his shaving kit to see if his diarrhea pills were still there. Well, maybe he should take a couple: This illness was worse than usual.

Three days later, the flight attendant and the sightseer were recovering. The grandfather was dead.

Crisis Time

In January 1991, epidemic cholera surfaced in South America for the first time in the 20th century. Originating in coastal Peru and rippling inland, the toxic tide reached 14 Latin American countries and spread as far north as Mexico, infecting nearly half a million residents and killing 4,000.

But on Valentine's Day 1992, cholera was the last thing on the minds of the 356 passengers and crew on Aerolineas Argentinas Flight 386. The flight had been uneventful, departing Buenos Aires, Argentina, stopping in Lima, Peru, and then landing in Los Angeles. But 24 hours later, diarrhea struck six of its passengers. On February 16, 25 more were affected. By February 17, the toll was up to 54 infected and one dead.

Sometimes I wonder if those early sufferers realized they were part of an outbreak. They certainly had no way to compare notes, dispersed halfway around the globe. On February 19, however, five Los Angeles-area hospitals reported stool cultures growing the bacterium Vibrio cholerae—all from travelers on Flight 386. That's when the warning bell sounded, and county health officials knew they had to try to find the remaining 351 passengers and crew. From a medical standpoint, they were late. Although most cholera patients suffer only mild to moderate diarrhea, others have been known to drop dead in a day.

There was a second reason to track the entire planeload of people. In order to pinpoint the source of the outbreak—presumably cholera-laced food served on board—health authorities had to survey as many passengers as possible, both with and without symptoms. At the same time, another question gnawed: Could public health detectives find the tainted food before other flights were exposed?

In Los Angeles, the crisis couldn't have come at a worse time. On the same weekend the cases broke, a fire closed the downtown offices of the county's acute communicable disease unit. In makeshift quarters miles from home, the frontline squad launched an investigation without computers, files, or phones. Looking back, the unit's chief, Laurene Mascola, recalls one silver lining. "The good thing... was that all of us were in one big, open area. And so we worked very efficiently, as we had few other distractions."

They still faced a tall order: reviewing customs declaration forms to identify heads of household on the flight, calling and faxing to determine who else was on board, talking to crew members (this required delicate negotiations with the airline), and cajoling caterers in Buenos Aires and Lima for menus, all the while juggling daily press conferences with news-hungry reporters.

Somehow, the wobbly effort succeeded. When investigators finally reached the sick and the well, compared their food diaries, and tested their lab samples, a shrimp salad prepared in Lima was the smoking gun. The other good news? Only Flight 386 had served the microbe-laden dish. On the other hand, of 194 passengers and crew who submitted blood or stool samples, 100 had undeniable evidence of recent cholera infection.

As a tropical-medicine specialist, I first heard about the rash of cholera from newspapers. It was a big story because the circumstances of the outbreak were so unusual. Nobody expects to get cholera on an airplane.

The disease typically occurs in regions where diarrheal illnesses spread easily because of inadequate sanitation. As many as 2 million infants and toddlers in developing countries still succumb to diarrhea every year. Most of these deaths are not from cholera, however. While the intestinal pathogens Rotavirus and toxin-producing Escherichia coli are pervasive in hygiene-poor countries, cholera is more often a sporadic wildfire that snakes through high-risk settings and even crosses oceans. When it's not wreaking havoc in a favela or a refugee camp, the organism's usual survival strategy is to hide out in brackish waters affixed to the horny exoskeletons of plankton and shellfish, an ancient form of bacterial hibernation.

What cholera and harmful E. coli have in common is a poison (also known as an enterotoxin) that binds to the inner lining of the small intestine. As a result, fluid and electrolytes are secreted rather than absorbed, and the affected gut gushes like a broken fire hydrant. Cholera toxin in particular is so potent that some victims purge as much as a liter per hour of nearly clear diarrhea, known to medical officers during the British raj as rice-water stool. Even today, if patients in this subgroup don't receive intravenous fluids or down massive amounts of a glucose-electrolyte solution like that found in popular sports drinks, they can die from desiccation.

Sadly, the grandfather from Flight 386 turned out to be a textbook example of a worst case. Three days after becoming infected, his blood pressure became dangerously low, his pulse weak and thready, his bowel bulging with fluid, while paradoxically, his oral membranes were so dry that one examiner's tongue depressor stuck to the roof of his mouth. By the time he reached an intensive care unit, he was comatose, and his tissues were dangerously acidic. Despite heroic rescue efforts, he died within hours.

Expert Care

Several years later, I received a phone call from the director of a nearby family-practice training program. "How would you like to discuss a case of traveler's diarrhea in next week's Grand Rounds?" he asked. "Sure," I said. "Just fax me the write-up." Soon I was reading about a middle-aged woman who had recently returned from El Salvador. On her flight to Los Angeles, she developed abdominal pain, vomiting, and profuse, watery diarrhea. After three days, too weak to even hold up her head, she was brought to the hospital. Her lab values told the rest of the story. Her blood was highly concentrated, her potassium dangerously low, and her kidneys had nearly shut down. 

This has got to be cholera, I thought. I wonder how the residents handled the case?

The following week, my question was answered when two young doctors-in-training stepped to the podium. What they described next would make any residency director glow with pride. Suspecting cholera from the outset, they infused six liters of an intravenous glucose-electrolyte solution known as Ringer's lactate solution, inserted a urinary catheter and a rectaI tube, and then meticulously charted I's and 0's (medicalese for"intake" and "output") through all orifices in order to replace the exact amount of fluid needed. They also started doxycycline, an antibiotic that lessens cholera's overwhelming fluid loss as well as its bacterial stool count. Their management was flawless. Slowly, the patient's kidneys began to work again, and her diarrhea abated. Five days later, the patient walked out of the hospital vibrant and well.

Of course, a little credit also goes to Flight 386. Where I live, it made cholera a household word.

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