CDC - Outbreak of Typhoid Fever Infections - August 12, 2010 - Salmonella

Investigation Announcement: Multistate Outbreak of Human Typhoid Fever Infections Associated with Frozen Mamey Fruit Pulp
August 12, 2010

CDC is collaborating with public health officials in two states and the U.S. Food and Drug Administration (FDA) to investigate an outbreak of Salmonella infections, serotype Typhi. Salmonella Typhi is the bacterium that causes typhoid fever. Typhoid fever is a very rare illness in the United States among non-international travelers and can cause serious symptoms, often times requiring hospitalization. Typhoid fever is contracted when food and water are contaminated by an infected individual and are then consumed by other people. Investigators are using DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.

As of 9:00am EDT on August 12, 2010, a total of 7 confirmed and 2 probable individuals infected with a matching strain of Salmonella serotype Typhi have been reported from 2 states since May 25, 2010. Confirmed cases are persons with illness on or after January 1, 2010 and a DNA fingerprint matching the outbreak strain. Probable cases are persons with a Salmonella Typhi infection and a strong epidemiologic link to the outbreak. The number of ill persons identified in each state with this strain is as follows: CA (3 confirmed and 2 probable) and NV (4 confirmed).

Among persons with reported illness onset dates available, illnesses began between April 10, 2010, and July 23, 2010. Infected individuals range in age from 4 to 31 years old and the median age is 21 years. Sixty-seven percent (67%) of cases are female and 100 percent report Hispanic ethnicity. Among 7 patients with available clinical information, 5 (71%) were hospitalized. Five (83%) of 6 patients interviewed reported no international travel in the 60 days prior to illness onset. As of August 12, 2010, no deaths attributed to this infection have been reported.

The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after May 30, 2010, might not yet be reported due to the time it takes between when a person becomes ill, when laboratory testing is completed, when the diagnosis is confirmed, and when the illness is reported. For typhoid fever outbreaks, this takes an average of 8-10 weeks. This delay is denoted by the gray box on the epi curve.

Investigation of the Outbreak
CDC and public health officials in two states conducted an epidemiologic study comparing foods eaten by ill and well persons. Among interviewed ill persons, 5 (71%) of 7 reported consuming frozen mamey fruit pulp in a milkshake or smoothie, also called a “batido” or “licuado.” Upon further investigation, it was found that 4 (80%) of 5 ill persons consumed Goya brand frozen mamey fruit pulp. Among well persons, 0 (0%) of 33 reported exposure to frozen mamey fruit pulp. No other food was found to be associated with illness. These results suggest that eating frozen mamey fruit pulp is a likely source of these illnesses. This investigation is ongoing. CDC and its public health partners will update the public on the progress of this investigation as information becomes available.

Mamey, also called “zapote” or “sapote,” is a tropical fruit grown primarily in Central and South America. It is prepared by removing the inner seed and consuming the flesh raw, or adding it to milkshakes, jellies, or other foods or beverages. When preparing frozen mamey fruit pulp, it is peeled and mashed, and then consumed as a shake or smoothie. Frozen mamey fruit pulp can be purchased in grocery stores throughout the U.S., and packages have a 2-3 year shelf life.


Clinical Features/Signs and Symptoms
Most persons infected with Salmonella Typhi develop high and sustained fever, headache, constipation, malaise, chills, and myalgia 2 to 5 weeks after infection. Infection is usually diagnosed by a blood culture. The illness can last from 3 to 4 weeks and infections may be severe or fatal if untreated. Typhoid fever should be treated with appropriate antimicrobial medications. More general information about Salmonella Typhi can be found here.

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CDC - Outbreak of Typhoid Fever Infections - August 12, 2010 - Salmonella




Aviso de investigación: Brote en varios estados de infecciones por fiebre tifoidea asociadas a la pulpa de fruta de mamey congelada

Los CDC están colaborando con los funcionarios de salud pública de dos estados y con la Administración de Drogas y Alimentos de los Estados Unidos (FDA) en la investigación de un brote infeccioso de Salmonella serotipo typhi. Esta es la bacteria que causa la fiebre tifoidea. Esta enfermedad es muy poco frecuente en los Estados Unidos en las personas que no viajan internacionalmente y puede causar síntomas graves, y a menudo requiere de hospitalización. La fiebre tifoidea se contrae cuando una persona infectada contamina los alimentos y el agua, que luego son consumidos por otras personas. Los investigadores están usando análisis del ADN de la bacteria Salmonella obtenido mediante pruebas diagnósticas para identificar casos de enfermedades que puedan formar parte de este brote.

Hasta las 9:00 a.m. EST del 12 de agosto del 2010, se han reportado un total de 7 casos confirmados y 2 casos probables de personas infectadas por una cepa similar de Salmonella serotipo typhi en dos estados, desde el 25 de mayo del 2010. Los casos confirmados son personas con enfermedades que se presentaron el 1.o de enero del 2010 o después y que tienen la huella genética característica de la cepa del brote. Los casos probables son personas con una infección por Salmonella typhi y con una fuerte conexión epidemiológica al brote. La cifra de personas enfermas identificadas en cada estado con esta cepa es la siguiente: California (3 casos confirmados y 2 probables) y Nevada (4 confirmados).

Entre las personas de las que se conoce la fecha reportada de aparición de la enfermedad, ésta empezó entre el 10 de abril del 2010 y el 23 de julio del 2010. Las personas infectadas oscilan entre los 4 y los 31 años de edad y la mediana de edad es de 21 años. El sesenta y siete por ciento (67%) de los casos son mujeres y el 100 por ciento indican que son del grupo étnico hispano. Entre los 7 pacientes de los que se dispone información clínica, 5 (71%) fueron hospitalizados. Cinco (83%) de los 6 pacientes entrevistados reportaron no haber viajado internacionalmente en los 60 días anteriores a la aparición de la enfermedad. Hasta el 12 de agosto del 2010, no se han reportado muertes atribuibles a esta infección.

El brote se puede describir visualmente con un gráfico en el cual se muestra el número de personas que se enfermaron diariamente. A este gráfico se le lama curva epidémica o epi curve. Las enfermedades que ocurrieron después del 30 de mayo del 2010, pueden no haberse reportado todavía, debido al tiempo que transcurre entre el momento en que la persona se enferma, se completan las pruebas de laboratorio, se confirma el diagnóstico y se reporta la enfermedad. En los brotes de fiebre tifoidea, este proceso toma un promedio de 8 a 10 semanas. Este retraso se marca en el recuadro gris en la curva epidemiológica.

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