The outbreak stretched over a long period of time, from 2007-2009, and involved a strain of Salmonella called Salmonella Java. During the course of the investigation, 75 people with S. Java infection were identified, although there were probably many more infected since diagnosed cases are usually the minority of the true total.
Individuals affected ranged in age from 1 month to 60 years, but the median age was only 2 years, which means the majority were very young children. The investigation started to focus on playgrounds and ultimately 207 sand samples were collected from 39 locations. Thirty-five isolates of S. Java were found, all from 6 playgrounds. These playgrounds had all received sand from the same depot over the preceding year, but Salmonella wasn’t found in samples from the depot.
To try to find a source, they started testing critters living in the area of parks, and found S. Java in 34 of 261 animals, mainly from long-nosed bandicoots (a marsupial indigenous to Australia).
It’s possible that this Salmonella strain is widely present in bandicoots (and other critters) in the area. I don’t know their defecation habits, but if they have a preference for pooping in sandboxes (like cats do), they could be contaminating play areas. The other possibility is that the sand was contaminated from some other source and the bandicoots were infected from the sand just like the people. There’s not really any easy way to figure that out.
Sandboxes have been associated with various disease outbreaks, but the overall risk is low and it’s certainly not a reason to keep kids away from them. Some things that can be done to reduce the risk of potential disease transmission from things in the sand include:
- Supervising kids to prevent them from sticking things in their mouths.
- Making sure they don’t eat or drink in the sandbox/playground.
- Making sure they wash their hands after playing in the sand.
- Covering the sandbox whenever it’s feasible (not always an option but good if it can be done) to help prevent animals from defecating in the sand.
More information about sandboxes and potential disease risks can be found on the Worms & Germs Resources – Pets page.
Image: Long-nosed bandicoot from Eastern Australia (Perameles nasuta)(click image for source)