MIAMI-DADE COUNTY, Fla. - Frozen fruit pulp imported from Guatemala was implicated in an outbreak of typhoid fever here that may have affected 15 people in the South Florida counties of Miami-Dade, Palm Beach and Pinellas.
Twelve cases were confirmed; three cases are waiting confirmation from the state laboratory. The patients ranged in age from 3 to 55 years old; all were hospitalized for treatment with good outcomes. Some continued treatment with outpatient antibiotics. The strain of Salmonella Typhi was the same in 11 cases tested by pulse-field gel electrophoresis, said Mary Jo Trepka, MD, MSPH, an epidemiologist with the Miami-Dade County Health Department.
Typhoid fever is rare in the United States; fewer than 400 cases occur each year, according to surveillance data from the Centers for Disease Control and Prevention (CDC). Trepka said that Miami-Dade County usually experiences 10 or fewer cases a year among its 2.1 million people. These usually occur among people who have traveled to a developing country. Miami-Dade County encompasses Miami and the surrounding areas.
"All of a sudden we had six cases within one month, and no one had been outside of the country," she explained. This triggered an epidemiological investigation that began with interviews to look for a common source. Salmonella Typhi is usually spread through contaminated water or food.
In the first several rounds of interviews, no common source was found. Finally, several people mentioned drinking mamey shakes. Mamey is a tropical fruit with a soft and smooth pink to red pulp. It is an ingredient in a popular frothy, tropical drink. "Mamey shakes are made by mixing mamey, often frozen mamey, with milk and ice or ice cream," she explained.
The researchers did a matched case-control study interviewing four controls for each patient. When required, because most of the study participants were Hispanic, the interviews were conducted in Spanish. "The only food item associated with Typhoid fever was the frozen mamey," said Trepka. The odds ratio was 8.4 and was statistically significant, she said.
The epidemiologists looked at where the drinks were consumed and found they were consumed in several restaurants as well as homes. Epidemiologists found El Sembrador brand frozen mamey in the freezers of the victims and in all the restaurants where some of the patients ate this product. The Food and Drug Administration (FDA), the Florida Department of Agriculture and Consumer Services, and the Florida Department of Health collected samples of frozen mamey for laboratory analysis; results are pending.
The FDA issued a warning to consumers not to eat El Sembrador brand frozen mamey from Guatemala or drinks made from El Sembrador brand frozen mamey due to the outbreak in South Florida The FDA said its warning was based on epidemiological data in the South Florida cases that showed a strong link between eating frozen mamey and getting typhoid fever.
Typhoid fever is a bacterial infection that causes persistent and high fever, abdominal cramps, loss of appetite and fatigue. Trepka said that the incubation period is generally one to two weeks after exposure, but cases can occur up to 60 days after exposure, so a few more cases might be found.
The FDA is continuing its traceback investigation to find the source and distribution of the frozen mamey products linked to the illnesses.
Typhoid fever in the United States is a rare illness most often acquired by traveling in developing countries. The illness is most often acquired by eating contaminated food or drinking contaminated water or beverages.
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