A high proportion of reptiles are asymptomatic carriers of Salmonella. Fecal carriage rates can be more than 90 percent; attempts to eliminate Salmonella carriage in reptiles with antibiotics have been unsuccessful and have led to increased antibiotic resistance. 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.
During the early 1970s, small pet turtles were an important source of Salmonella infection in the United States; an estimated four percent of families owned turtles, and 14 percent of salmonellosis cases were attributed to exposure to turtles. In 1975, the Food and Drug Administration prohibited the distribution and sale of turtles with a carapace smaller than four inches; many states prohibited the sale of such turtles. These measures resulted in the prevention of an estimated 100,000 cases of salmonellosis annually. 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.
Because young children are at increased risk for reptile-associated salmonellosis and severe complications (e.g., septicemia and meningitis), reducing exposure of infants or children less than five years old 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.