Tenants let mice get out of hand...8 month old in home

[Bryan M.]

My tenants recently let me know they had seen some mice in their duplex unit. I went over to look at the situation and it seems like an issue that's been going on for much longer than they initially explained. Here are some quick facts - 

- Unit is cluttered with laundry, empty boxes, random crap, empty soda bottles ect. (It's bad but not as bad as you may be imagining.)

- Some food out but mostly covered, however, lots of crumbs - No vacuuming going on.

- Excessive mice droppings along walls.

- I was told they found a mouse in the couch.

- They have put traps out and caught some.

- Young mother (mentally disabled and daughter of tenant who pays the rent) has an 8 month old.

I went over and put multiple bait stations and traps on the advice of my pest control guy. He said he wouldn't do anything different. 

With an 8 month old in the home it's not sanitary. The baby is not crawling yet but it will soon no doubt. I have told them to clean up but I'm wondering what your opinion is on contacting a certain authority about the child's care. 

I try to be ethical and moral in everything I do, but when should a landlord step in?

Thanks BP!