DUKKI, Pakistan — Outside her small, mud-walled house in western Pakistan, Gul Saima is cajoling her 3-year-old son to take a few steps. He cries as he struggles to lift his right leg and arm, both stiff and unyielding.

Overhead is a banner featuring a photo of a smiling boy on crutches. Ms. Saima, 38, is illiterate and cannot read the words printed in Urdu: “Don’t let your child’s dreams go to waste.” But the connection between the smiling boy and her son, Sayyad Karam, is painfully clear: Both have the paralysis that often follows a polio infection.

The health authorities hung the banners throughout the area for a polio awareness campaign — and apparently put one on Ms. Saima’s house in a clumsy attempt to show officials, many of whom have visited since Sayyad’s polio was diagnosed last month — that they are committed to it.

Sayyad’s diagnosis was a significant event, and not only for his family. So far, his is the only new polio case of the year in Pakistan — a historical low, according to official figures in a country where eradication efforts have been repeatedly foiled by ignorance, mistrust and militant attacks on vaccination teams.