Investigation Details

Posted January 11, 2022

January 11, 2022

CDC and public health officials in several states are collecting different types of data to investigate a multistate outbreak of Salmonella Uganda infections.

Epidemiologic and laboratory data show that contact with bearded dragons is making people sick.

Epidemiologic Data

As of January 10, 2022, a total of 44 people infected with the outbreak strain of Salmonella Uganda have been reported from 25 states (see map). Illnesses started on dates ranging from December 24, 2020, to December 2, 2021 (see timeline).

Sick people range in age from younger than 1 to 84 years, with a median age of 27, and 8 ill people were children under the age of 5. Of 43 people with sex information, 27 (63%) are female. Of 37 people with information available, 15 (41%) have been hospitalized. No deaths have been reported.

The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 2 to 4 weeks to determine if a sick person is part of an outbreak.

State and local public health officials are interviewing people about the animals they came into contact with in the week before they got sick. Of 33 people interviewed, 21 (64%) reported owning or touching bearded dragons or their supplies. People reported getting their bearded dragons from various places, including pet stores and online.

Laboratory Data

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause gastrointestinal illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples are closely related genetically. This means that people in this outbreak likely became sick from contact with the same type of animal.

On November 19, 2021, Oregon Health Authority collected samples from a bearded dragon in a sick person’s home for testing. WGS showed that the Salmonella on the animal is closely related to bacteria from sick people. This means that people likely got sick from touching bearded dragons.

Whole genome sequencing of bacteria from 44 people’s samples and one bearded dragon sample did not predict any antibiotic resistance. Standard antibiotic susceptibility testing of two people’s samples by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also found no resistance. Most people with Salmonella illness recover without antibiotics.

Public Health Actions

CDC advises that you always take steps to stay healthy around your pet bearded dragon:

  • Wash your hands
  • Don’t kiss or snuggle your bearded dragon
  • Don’t eat or drink around it
  • Keep it out of the kitchen
  • Keep its supplies and habitat clean
Previous Updates

Epidemiologic and laboratory data show that contact with backyard poultry is making people sick.

Since the last update on July 23, 2021, 191 more illnesses have been added to this outbreak investigation.

Epidemiologic Data

As of August 31, 2021, a total of 863 people infected with one of the outbreak strains have been reported from 47 states and the District of Columbia (see map). Illnesses started on dates ranging from December 15, 2020, to August 8, 2021 (see timeline).

Age information was available for 860 people. Their ages range from less than 1 to 97 years, with a median age of 36 years, and 220 (26%) are young children under 5 years. Of 842 people with sex information available, 493 (59%) are female. Of 617 people with information available, 203 (33%) have been hospitalized. Two deaths have been reported, one from Indiana and one from Virginia.

The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.

State and local public health officials are interviewing people about the animals they came into contact with the week before they got sick. Of the 527 people interviewed, 365 (69%) reported contact with backyard poultry before getting sick.

Laboratory Data

WGS was also used to identify any predicted antibiotic resistance for bacteria from 845 sick people’s samples, 4 animal samples, and 7 environmental samples. Of the 856 samples, 304 (36%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.7%), ampicillin (1.1%), chloramphenicol (0.4%), cefoxitin (0.7%), ceftriaxone (0.7%), ciprofloxacin (0.1%), gentamicin (2.1%), kanamycin (0.4%), streptomycin (33.6%), sulfamethoxazole (2.7%), tetracycline (32.1%), and trimethoprim-sulfamethoxazole (0.2%). Testing of five clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin and kanamycin were not tested by this method).

Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.