March 13, 2020

CDC and public health officials in several states investigated a multistate outbreak of human Salmonella Typhimurium infections linked to contact with small pet turtles.

Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using a standardized laboratory and data analysis method called whole genome sequencing (WGS). CDC PulseNet manages a national database of these sequences that are used to identify possible outbreaks. WGS gives investigators detailed information about the bacteria causing illness. In this investigation, WGS showed that bacteria isolated from ill people were closely related genetically. This means that people in this outbreak were more likely to share a common source of infection.

A total of 35 people infected with the outbreak strain of Salmonella Typhimurium were reported from 9 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Illnesses started on dates ranging from July 29, 2019, to December 24, 2019. Ill people range in age from 1 to 71 years, with a median age of 7. Children younger than 12 account for 69% (24 of 35) of ill people. Sixty-three percent of ill people were female. Eleven hospitalizations were reported among the 31 ill people with information available. No deaths were reported. Of 30 ill people with ethnicity information available, 19 (63%) are Hispanic.

WGS analysis did not identify antibiotic resistance in 35 bacterial isolates (34 clinical isolates from ill people and one isolate from a turtle). One additional clinical isolate contained a resistance gene for ampicillin. This resistance likely will not affect the choice of antibiotic used to treat most people. Testing of three clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory found no resistance.

Investigation of the Outbreak

Epidemiologic and laboratory evidence indicated that contact with small pet turtles was the likely source of this outbreak.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 24 people interviewed, 20 (83%) reported contact with a pet turtle. Thirteen people remembered the size of their turtle, and all of them reported contact with turtles whose shells were less than 4 inches long. Ill people reported buying small pet turtles from flea markets, swap meets, pet stores, or receiving turtles as a gift. Testing of a turtle and its environment at one ill person’s home yielded the outbreak strain.

Previous Salmonella outbreaks have been linked to pet turtles with a shell length less than 4 inches. In 1975, the U.S. Food and Drug Administration bannedexternal icon the sale and distribution of turtles with shells less than 4 inches long due to their link to Salmonella illnesses in people.

Turtles can carry Salmonella germs that can make people sick, regardless of their size or where they were purchased. Pet owners should always follow steps to stay healthy around their pet.

As of March 13, 2020, this outbreak investigation is over.