11/23/2011 11:55 am ET

WATCH: Mystery Illness Hits Cruise Ship, US Tourist Dies

An American woman has died, and 86 others have fallen ill aboard a cruise ship that was struck by a mystery illness, CNN reports.

According to The Examiner, only 79 passengers were sickened.

The MS Veendam, operated by Holland America, was on a South American tour and docked Tuesday in Rio de Janiero. Forensic doctors are investigating the elderly woman's death. It's not believed to be related to the "mystery illness," as ship doctors told police she suffered from hypertension and diabetes.

AFP reports the mystery illness has been solved, and was simply the stomach flu.

Last week, a 60-year-old Celebrity Cruise passenger died while on an excursion, prompting the line to cancel parasailing trips.

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