Why are some kids sent to school so dirty/filthy?

This is a new one. Student had feces on their hands and forearms. This kid is 8 years old. Washes their hands often throughout the day but it stayed on their clothes. Some kids are so dirty and smelly some teachers move their desks away from the students. I have multiple kids with body odor, bad breath. I love kids but some are sent to school filthy. I’m assuming parents are neglectful. What do I do about an 8 year old with poop on their arms? They don’t know how to clean. I sent them to the nurse. Have you had kids this dirty? How did you handle it?