A nurse quarantined on her return to the US from treating Ebola patients in Sierra Leone has criticised the way she was dealt with at Newark airport.
Kaci Hickox said the experience was frightening and could deter other health workers from travelling to West Africa to help tackle the Ebola virus.
Illinois has become the third state after New York and New Jersey to impose stricter quarantine rules.
Meanwhile the US ambassador to the United Nations is to visit West Africa.
Samantha Power will travel to Guinea on Sunday, continuing later to Liberia and Sierra Leone – the three worst-hit countries.
“For me the benefits of having first hand knowledge of what is happening in these countries gravely outweighs the almost nonexistent risk of actually travelling to these countries, provided I take the proper precautions,” she said on Saturday.
She said she hoped her trip would “draw attention to the need for increased support for the international response”.
The White House has expressed concern that strict quarantine restrictions such as those imposed by state governments in New York, New Jersey and Illinois could put off aid workers and others travelling to West Africa to help mitigate the crisis at its source.
More than 10,000 people have contracted the Ebola virus, with 4,922 deaths, according to the World Health Organization’s latest figures.
Only 27 of the cases have occurred outside Sierra Leone, Liberia and Guinea.
Ms Hickox, of medical charity Doctors Without Borders, described seeing a “frenzy of disorganisation, fear and most frightening, quarantine” on her return from Sierra Leone on Friday.
Writing for The Dallas Morning News, she asked whether fellow health workers would “face the same ordeal”.
“Will they be made to feel like criminals and prisoners?” she questioned.
She said she was kept in isolation at the airport terminal for seven hours and given only a cereal bar to eat.
She also denied that she had had a fever, saying she was merely flushed because of the upset caused by her treatment at the airport.
Though Ms Hickox tested negative in a preliminary test for the virus, she will remain under quarantine for three weeks and continue to be monitored by health officials.