Reptile-associated salmonellosis - selected states, 1994-1995

Morbidity and Mortality Weekly Report, May 5, 1995

Reptiles are popular as pets in the United States: an estimated 7.3 million pet reptiles are owned by approximately 3% of households (G. Mitchell, Pet Industry Joint Advisory Council, personal communication, 1995). Because the most popular reptiles species will not breed if closely confined, most reptiles are captured in the wild and imported. The number of reptiles imported into the United States has increased dramatically since 1986 and primarily reflects importation of iguanas (27,806 in 1986 to 798,405 in 1993) (M. Albert, Fish and Wildlife Service, U.S. Department of the Interior, personal communication, June, 1994).

A high proportion of reptiles are asymptomatic carriers of Salmonella. Fecal carriage rates can be more than 90%[3]; attempts to eliminate Salmonella carriage in reptiles with antibiotics have been unsuccessful and have led to increased antibiotic resistance[1,4]. A wide variety of Salmonella serotypes has been isolated from reptiles, including many that rarely are isolated from other animals (reptile-associated serotypes). Reptiles can become infected through transovarial transmission or direct contact with other infected reptiles or contaminated reptile feces. High rates of fecal carriage of Salmonella can be related to the eating of feces by hatchlings - a typical behavior for iguanas and other lizards - which can establish normal intestinal flora for hindgut fermentation[5].

During the early 1970s, small pet turtles were an important source of Salmonella infection in the United States; an estimated 4% of families owned turtles, and 14% of salmonellosis cases were attributed to exposure to turtles[6]. In 1975, the Food and Drug Administration prohibited the distribution and sale of turtles with a carapace <4 inches; many states prohibited the sale of such turltels. These measures resulted in the prevention of an estimated 100,000 cases of salmonellosis annually[6]. However, since 1986, the popularity of iguanas and other reptiles that can transmit infection to humans has been paralleled by an increased incidence of Salmonella infections caused by reptile-associated serotypes[7].

Because young children are at increased risk for reptile-associated salmonellosis and severe complications (e.g., septicemia and meningitis)[7-9], reducing exposure of infants or children aged <5 years to reptiles is particularly important. The risks for transmission of Salmonella from reptiles to humans can be reduced by avoiding direct and indirect contact with reptiles (see box).

Recommendations for Preventing Transmission of Samonella

From Reptiles to Humans

* Person at increased risk for infection or serious complications of salmonellosis (e.g., pregnant women, chilfren aged <5 years, and immunocompromised persons such as persons with AIDS) should avoid contact with reptiles.

* Reptiles should not be kept in child-care centers and may not be appropriate pets in households in which persons at increased risk for infection reside.

* Veterinarians and pet store owners should provide information to potential purchasers and owners or reptiles about the increased risk of acquiring salmonellosis from reptiles.