Two days after holding a baby albino corn snake at a King County pet store, a 5 year-old child developed an acute illness characterized by fever and diarrhea and was hospitalized for 4 days. Salmonella Arizonae (S. Arizonae), serogroup S, a type of Salmonella never before reported in a King County resident, was isolated from the child's stool. Fecal matter from the corn snake was subsequently cultured and S. Arizonae, serogroup S was recovered. The DNA patterns of the two isolates were compared by Pulsed Field Gel Electrophoresis (PFGE) and the isolate from the child and the isolate from the snake were identical.

Many animals shed Salmonella, but reptiles and amphibians are particularly at risk for being chronically colonized with Salmonella. Also, in contrast to birds which sit up on a perch, reptiles, because of their housing, have frequent contact with their own feces. Antibiotic treatment of reptiles shedding Salmonella is not indicated because the animals are rapidly re-colonized and treatment fosters carriage of antibiotic resistant strains. Reptiles are increasingly popular pets in the United States, with an estimated 3% of households owning a reptile. Because they don't breed well in confinement, they are often captured in the wild and imported. The number of reptiles and amphibians imported into the U.S. has increased dramatically since 1986. The fact that a reptile is imported increases the likelihood that it will harbor Salmonella serotypes rarely isolated in the U.S. such as Java, Marina, Stanley, Poona, Flint, and Chameleon. Such rare Salmonella serotypes are increasingly isolated from humans, reflecting the increase in the number of reptiles as pets.

Public Health has increased surveillance for reptile-associated Salmonella cases (RASC) since January 2001 by 1) consistently inquiring about patient contact with reptiles, and 2) collecting environmental and peri-cloacal swabs from implicated reptiles when permitted by the owner. In just over one year of enhanced surveillance, 23 RASC have been identified in King County, approximately 10% of all reported cases of salmonellosis. In collaboration with staff at both King County and Washington State Department of Health (DOH) Laboratories, we examined clinical specimens from 14 implicated reptiles associated with these RASC (see Table 1) and Salmonella was isolated from six (some cases had more than one reptile that was tested). In four of these six, the human and the reptile isolates were identical by PFGE. Additionally, in households with more than one reptile, up to 5 serotypes of Salmonella were isolated. In addition to the case described above, we have identified three additional cases of salmonellosis in which the reptile in the household was colonized with the identical strain of Salmonella:

• A 20 year-old male became infected with S. Typhimurium from his red-tailed boa.
• A 3 month-old infant was infected with S. Senegal, serogroup F from a high desert tortoise (serogroup F is rarely isolated from humans).
• An 18 month-old infant was infected with S. Monschaui from indirect contact with a Mexican milk snake.

Because reptiles can harbor multiple serotypes of Salmonella simultaneously and shed these organisms intermittently, it's likely that many more RASC cases were caused by the suspect reptiles but the organism was not recovered at the time of culture.

Based on the risk of reptile-associated Salmonellosis and the increased severity of illness, the Centers for Disease Control and Prevention (CDC) recommends that:

More information on reptile-associated Salmonella cases in King County is available in the September 2001 edition of the Epi-Log available online at: www.metrokc.gov/health/providers.

A review of reptile-associated salmonellosis cases reported nationally between 1996 and 1998 is available online at: www.cdc.gov/mmwr/preview/mmwrhtml/mm4844a1.htm. Educational posters and brochures developed by CDC and the Pet Industry Joint Advisory Council (PIJAC) for use by veterinarians and pet stores on safe pet reptile handling are available by calling 1-800-553-7387. Please contact Shelly McKeirnan at 206-296-4717 if you have questions about this article or salmonellosis.