Salmonella Outbreak Linked to Bearded Dragons

Research in Action

5 March 2024

A joint Canada-U.S. investigation, between Public Health Ontario, the Public Health Agency of Canada and the U.S. Centers for Disease Control and Prevention, uncovered a link in a 2021-2022 Salmonella outbreak that disproportionately sickened many infants in North America.

Fourteen cases in total – 12 in the U.S. and 2 in Ontario – were reported of Salmonella Vitkin. While cases of Salmonella in people are fairly common, some strains, including those found in reptiles such as lizards, snakes and turtles, are rare. 

Dr. Katherine Paphitis, Enteric Zoonotic Specialist at Public Health Ontario, and other public health partners used whole-genome sequencing data to identify the outbreak strain and linked it to households that had bearded dragons as pets. Their research article about the outbreak, which highlighted its investigation and epidemiology results, was featured in the CDC’s Emerging Infectious Diseases journal last month.

We spoke with Dr. Paphitis to learn more about the key findings and unique discoveries emerging from the study:

Why is this study important?

Since the Salmonella serotype implicated in this investigation is rare in North America, there was not a lot of information available regarding potentially causative exposures.

Given our finding that bearded dragons were the source of this outbreak, we thought it was important to share this information with the scientific community, both to contribute to the body of published literature on salmonellosis and source attribution, and to provide a resource for individuals involved in human case investigation and outbreak management who may encounter this serotype.

Additionally, I think this outbreak highlighted the importance and benefit of cross-border collaboration with our United States public health partners, which was vital to this particular investigation.

What are main takeaways from the study?

Our main takeaways were twofold, first that this outbreak really showcased how cross-border and agency collaboration and communication can help to identify and investigate outbreaks that may not be detected through routine surveillance methods.

Second, it reinforced the importance of educating pet owners so they can make an informed choice regarding the type of pet they choose to bring into their household and are aware of things they can do at home to minimize the risk of infection.

What unique discoveries emerged from the study, if any?

I’m particularly interested in potentially overlooked pathways of zoonotic disease transmission. I think this outbreak highlighted the importance of providing bearded dragon owners with information on how Salmonella can be spread from reptiles to people, so that they can take measures to prevent transmission of the bacteria from their pets to those in their household.

In this outbreak, we suspected that some indirect transmission of infection may have occurred through contact between infants and the contaminated clothing of caregivers, or through contact with contaminated environmental surfaces within the home. If bearded dragon owners aren’t aware of this risk, they may not think to change their clothing after holding their reptile and before holding a child, or they may allow their bearded dragon to roam on kitchen counters or other surfaces that may be harder to clean.

What advice would you give pet owners who are thinking of adopting bearded dragons as pets?

Pets are important members of many households and some reptiles, including bearded dragons are becoming more popular as pets. I’d encourage potential and current pet owners to do their homework before bringing a new pet into their household.

It’s also important to learn about the potential risks that are inherent to a particular animal, and to make an informed choice regarding the type of pet that is right for you and your household, including things you can do to minimize the risk of disease transmission from pets to people and vice versa, so that everyone remains healthy.

How can pet owners who have exotic pets prevent infection?

First it’s important to be aware that some exotic pets, such as reptiles may be carrying Salmonella and other bacteria, and that pet owners and other household members may be exposed through direct or indirect contact.

To minimize the risk of exposure:

  • Anyone handling reptiles, their bedding, feed or environment should wash their hands with soap and water afterwards;
  • Have dedicated food and water dishes for your pet and wash them separately from those used by people in the household; and
  • Avoid letting them free roam on surfaces that can’t be cleaned and disinfected, and ideally never on kitchen or bathroom countertops to avoid potential cross-contamination.

I think sometimes what we see is that people typically consider their pets to be members of their family, so they may relax some of the boundaries you might have with a wild animal for example, so they may be more likely to let their pet lick their face, eat off of their plate, or sleep in their bed, all of which can increase the potential risk of exposure.

Learn more about Dr. Paphitis’ research in the Emerging Infectious Diseases Journal article and explore coverage in notable media outlets below:

For more information, please visit PHO’s Salmonella and News pages.

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Published 5 March 2024