An outbreak of salmonellosis among children attending a reptile exhibit at a zoo☆,☆☆,★

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Abstract

Objective: In January 1996, an outbreak of diarrhea caused by Salmonella Enteritidis occurred in children attending a Komodo dragon exhibit at a metropolitan zoo. We sought to determine the extent of the outbreak and mode of transmission. Study design: A case-control study was conducted. Controls were randomly selected from zoo membership lists and matched to patients by age group and date of exhibit visit. Results: Of 65 patients identified, 39 had confirmed and 26 had suspected cases. The median age was 7 years (range, 3 months to 48 years); 55% were male, and 56% had bloody diarrhea. Twenty-six patients and 49 controls were enrolled in the case-control study. No patients and two (4%) controls reported touching a dragon; however, 83% of patients but only 52% of controls touched the wooden barrier that surrounded the dragon pen (odds ratio = 4.0, 95% CI 1.2 to 13.9). Washing hands at the zoo after visiting the dragons was highly protective (OR = 0.14, 95% CI 0.03 to 0.7). Cultures from the patients, one dragon, and the exhibit barriers yielded Salmonella Enteritidis, phage type 8. On the basis of an attack rate of 4.3% among exhibit attendees under 13 years old on whom data were collected, we estimate that 315 additional cases of salmonellosis occurred among visitors in this age group. Conclusion: This large outbreak demonstrates the importance of environmental contamination in the transmission of Salmonella from reptiles, and the protective value of hand washing. Recommendations regarding reptile exhibits and reptilian pets should emphasize this indirect route. (J Pediatr 1998;132:802-7)

Section snippets

Epidemiologic Investigation

A confirmed case was defined as illness in a person who went to the dragon exhibit on January 11, 1996, or from January 13 through 21, 1996, from whom a stool specimen yielded S. Enteritidis. A suspected case was defined as illness in a person who went to the dragon exhibit on the above dates and experienced diarrhea (≥ three loose bowel movements in 24 hours) within 8 days of the exhibit visit. A secondary case was defined as illness in a person who was classified as having either a confirmed

Clinical and Epidemiologic Findings

We identified 65 ill patients, 39 with culture-confirmed cases, and 26 with suspected cases. Forty-eight patients, 33 with culture-confirmed and 15 with suspected cases, were the first person to become ill in their household. In all instances, the second person to become ill in each household had also visited the exhibit. Most patients visited the exhibit on the weekend of January 13, 14, and 15 (Figure).

Figure. Date of dragon exhibit visit among patients with culture-confirmed or suspected

DISCUSSION

This report describes the first known outbreak of human salmonellosis caused by reptile exposure at a zoologic park. This investigation demonstrates that transmission of Salmonella from reptiles can occur via environmental contamination. The Komodo dragons, one of which was infected with S. Enteritidis, stood in fecally contaminated mulch and frequently placed their front paws on the tops of the barriers. The visitors frequently touched these same barriers and most likely became infected when

Acknowledgements

The authors thank M. Rau, D.J. Dutton, J. Gossack, J. Pape, S. Shah, N. Bean, P. Hayes, B. Mertens, R. Cambre, and the staff of the Denver Zoo for their assistance with this investigation.

References (32)

  • RL. Haddock

    Salmonella in vacuum cleaners

    Lancet

    (1986)
  • RB Chalker et al.

    A review of human salmonellosis: III. Magnitude of Salmonella infection in the United States

    Rev Infect Dis

    (1988)
  • CDC

    Salmonella surveillance: annual tabulation summary, 1993-1995

    (1996)
  • PR Cieslak et al.
  • C Dalton et al.

    Iguana-associated salmonellosis in children

    Pediatr Infect Dis J

    (1995)
  • DM Ackman et al.

    Reptile-associated salmonellosis in New York State

    Pediatr Infect Dis J

    (1995)
  • R Reporter et al.

    Rare serotypes of Salmonella associated with iguana exposure

  • J Mermin et al.

    Iguanas and Salmonella Marina infection in children: a reflection of the increasing incidence of reptile-associated salmonellosis in the United States

    Pediatrics

    (1997)
  • CDC

    Reptile-associated salmonellosis — selected states, 1994-1995

    MMWR

    (1995)
  • DG Kleinbaum

    Logistic regression a self-learning text

  • JJ Farmer et al.

    Enterobacteriaceae

  • WH. Ewing

    The genus Salmonella

  • LR Ward et al.

    A phage-typing scheme for Salmonella Enteritidis

    Epidemiol Infect

    (1987)
  • National Committee for Clinical Laboratory Standards

    Performance standards for antimicrobial disk susceptibility tests

    (1995)
  • EV Morse et al.

    Salmonellosis: an environmental health problem

    J Am Vet Med

    (1974)
  • E Mitscherlich et al.

    Microbial survival in the environment: bacteria and rickettsiae important in human and animal health

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    ☆

    From the Foodborne and Diarrheal Diseases Branch, and the Biostatistics and Information Management Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Disease, and the Epidemic Intelligence Service, Epidemiology Program Office, Centers for Disease Control and Prevention, Atlanta; University of Medicine and Dentistry New Jersey, New Jersey Medical School, Newark; and the Colorado Department of Public Health and Environment, Denver.

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    Reprint requests: Cindy R. Friedman, MD, Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention, Mailstop A-38, 1600 Clifton Rd., Atlanta, GA 30333.

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