Polio — Acute Flaccid Asymmetric Paralysis

A 4-year-old child from rural Maharashtra presents with a 2-week history of fever, headache, and neck stiffness followed by acute onset of weakness in the left lower limb. On examination, the left leg shows flaccidity, absent knee and ankle reflexes, and muscle atrophy. Sensation is intact throughout. The structure marked **A** in the diagram represents the clinical hallmark of this presentation. Which of the following is the MOST LIKELY causative organism and the PRIMARY public health intervention required in India?