Public sandboxes are bacteria breeding grounds.
Fact: If it's a public sandbox, or even your own sandbox left uncovered, there is no way to keep cats and critters out of it, and they will consider it a public litter box. Hear me now, believe me later.
Your child is at risk if they stick their fingers in their mouth after playing in sand soiled with animal feces. This can cause pinworms, roundworms, and hookworms, which can lead to fever, stomach pains, and intense itching of the bum-bum.
They are also contagious and are spread from person to person, or by touching bedding, food, or other items contaminated with the worm's eggs.
Children are especially vulnerable to hookworms, A hookworm infection occurs when larvae come into contact with human skin, through contaminated soil or feces (OR SANDBOXES). They penetrate the skin, making their way through the lungs to the small intestine, where they latch on and grow into adults, laying more eggs. They feed off the blood of the infected person, which can lead to anemia.
And also a serious gross-out effect.