In the month since a Liberian man infected with Ebola traveled to Dallas, where he later died, the nation has marinated in a murky soup of understandable concern, wild misinformation, political opportunism and garden-variety panic.

Within the escalating debate over how to manage potential threats to public health — muddled by what is widely viewed as a bungled effort by government officials and the Dallas hospital that managed the first case of Ebola diagnosed in the United States — the line between vigilance and hysteria can be as blurry as the edges of a watercolor painting.

A crowd of parents last week pulled their children out of a Mississippi middle school after learning that its principal had traveled to Zambia, an African nation untouched by the disease.

On the eve of midterm elections with control of the United States Senate at stake, politicians from both parties are calling for the end of commercial air traffic between the United States and some African countries, even though most public health experts and the Centers for Disease Control and Prevention said a shutdown would compound rather than alleviate the risks.