Since the 50% of school funding comes from the local regions, 40% from the state, then 10% from the government, if a school is in a poor region they will not have money to fund their school. If people are poor that live in that region chances are they do not have health insurance. Schools that barely get by do not have the funding for education let alone the supplies or money to take care of the sick children that have all odds against them.
Poor urban children are coming to school with out treatment infecting the healthier children creating a continuous cycle.