The new monitoring rules to be placed on travelers coming into the United States from three Ebola-affected countries in West Africa form a smart and workable response to a complex public health question. The measures should be more effective than a misguided ban on all travelers from Guinea, Liberia and Sierra Leone, which many in Congress have been demanding.

Starting Monday in six states, and rolled out in other states soon after, travelers who visited those countries will be required to report their temperature and any other symptoms to state or local health officials daily for 21 days, the maximum incubation period for the disease to develop. The officials will be responsible for finding and possibly detaining anyone violating these rules.

The domestic Ebola concerns began with the case of a Liberian man, Thomas Eric Duncan, who had no temperature or other symptoms when he passed through screening in his home country and only became visibly sick after arriving in Dallas, where he died in a major hospital and infected two nurses who cared for him.

The worries increased last week when an American doctor who had treated patients in Guinea and returned to New York tested positive for the virus.

Duncan's case led federal officials to add a layer of screening at this end, requiring travelers to have their temperature and symptoms checked and to be questioned about possible contacts with Ebola. Last week, the administration said all travelers who have been in the three African nations can enter the United States only through the five airports that have health screeners in place. But it is not clear that airport screening would have identified Duncan, since he was not yet ill and may not have realized he had contact with an Ebola victim. The tighter monitoring announced last week, however, probably would have identified him earlier and prompted treatment that might have saved his life and reduced possible exposure.

The new measures surely make unnecessary a harmful ban on all travelers who have been in the three countries. Federal health officials say most travelers returning from those countries are either American citizens or longtime legal residents. They include volunteers who have been battling the epidemic, journalists and federal health experts, among others. Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, who visited West Africa recently, would presumably have been prevented from returning if there had been a travel ban.

A ban would discourage volunteers from joining the fight against Ebola and make it harder to bring the epidemic under control, the surest way to protect this country from imported cases.