Do i have a right to say something?

i go to a play group with a woman and twice she has taken her son when he's been ill the first time he came with swine flu and ended up putting my 3 month old son in hospital. The second time he had a stomach bug and now both my kids have been violently throwing up all week. My husband has missed time at work to help look after the kids and me and he's had to take time off when he's been ill, so we've missed a wage for a few days. Do i have the right to tell this woman she should keep her kids at home when they're ill? What would you guys do?