Swimming with Little Turtles and Human Salmonellosis
Review & Commentary
By Maria D.Mileno, MD
Maria Mileno, Director of Travel Medicine, The Miriam Hospital, and Associate Professor of Medicine and Director, International Travelers Clinic, Brown University School of Medicine, Providence, RI.
Dr. Mileno reports no financial relationships relevant to this field of study.
Synopsis: Exposure to small turtles has lead to a multistate outbreak of Salmonella paratyphi B var. Java infections. This MMWR report summarizes the epidemiologic and laboratory investigation conducted by CDC and state and local health departments since the first reported illness on 5/4/07.
Source: Multistate Outbreak of Human Salmonella Infections Associated with Exposure to Turtles, United States, 2007-2008. MMWR, January 25, 2008 / 57(03); 69-72.
On August 31, 2007 a 13-year-old girl present ed to a South Carolina emergency department with a 5-day history of bloody diarrhea, abdominal cramps fever and vomiting. She required intravenous fluids but was not hospitalized. She was treated with trimethoprim-sulfamethoxazole, and her illness resolved within 7 days. On the same day a 15-year-old girl was hospitalized with similar symptoms and acute renal failure in North Carolina. During October three other symptomatic individuals in Ohio had stool cultures with the identical isolate as the first patient, Salmonella paratyphi B var. Java with Xba I pattern on pulse field gel electrophoresis (PFGE). Further investigation revealed that both of the cases who were patients in August swam in an unchlorinated in-ground swimming pool along with the first girl's two pet turtles. Both turtles had carapaces less than 4 inches long. A water sample revealed the same isolate. The second patient did not have stool cultures. The Ohio Department of Health documented evidence of turtle-associated salmonellosis upon isolating the organism from a patient who had exposure to a small turtle the week before illness, as well as from the patient's pet turtle and the turtle's water habitat. Given this clustering of cases the CDC began a multistate investigation. Cases were identified by symptoms and a positive specimen with the identical outbreak strain upon review of all PFGE-typed isolates in the Pulse Net data base of CDC. No deaths were reported.
There were a total of 103 cases reported from 33 states. State and local health departments collected information from enteric disease questionnaires. In terms of clinical symptoms, 51 of 78 (65%) had bloody diarrhea with a median duration of 7 days. Twenty-four of 80 were hospitalized for a median duration of 4 days. Of those asked about turtle exposure, 47 of 80 (59%) reported turtle exposure during 7 days before the onset of illness.
A case-controlled study using a telephone questionnaire was set up using age and neighborhood matched controls to focus on exposure to turtles, other reptiles or tropical fish aquariums during a 7-day exposure period. If participants reported exposure they were asked in depth questions about the nature of the exposure. Turtle size type and source were also explored. All participants were asked about their awareness of the association between contact with reptiles and Salmonella infection. Seventy case-patients and 45 matched controls were enrolled in the study.
Significant findings included the following: turtle exposure occurred in 44 of 70 (63%) case patients compared with 2 of 45 (4%) controls. Twelve of 60 (20%) case patients and 13 of 45 (29%) controls reported awareness of an association between reptiles and salmonellosis. Seventy-seven percent of patients were exposed at home, 20% were exposed at a friend or relative's house and 2% (one patient) was exposed in the outdoors. Twenty-eight of 42 (67%) reported that they held or touched turtles; 24 of 42 (57%) fed the turtle; 29/42 (69%) had contact with the turtle's habitat by changing its water or cleaning the cage and 4 of 42 (10%) reported kissing the turtle or putting it in his or her mouth. Measurements of the turtles showed that 37 of 43 had carapace lengths of less than 4 inches.
Strains matching the outbreak strain have been isolated from 6 turtles or water from their habitats in the homes of case patients from California, North Carolina, Ohio and Washington. Investigations are ongoing in order to determine whether the turtles have a common origin.
Reference:
- CDC. Turtle-associated salmonellosis in humans --- United States, 2006-2007. MMWR. 2007;56:649-52.
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