Requiring quarantines for doctors and nurses returning to the United States from West Africa is having a "chilling effect" on the fight against Ebola, Doctors Without Borders/Médecins Sans Frontières (MSF) said on Thursday.

In an email exchange with Reuters, MSF executive director Sophie Delaunay said the forced isolation in health workers’ home countries has led the humanitarian aid group to discuss shortening assignments in West Africa so that workers can avoid "rising stigmatization at home and possible quarantine."

Widespread panic and misinformation about the spread of Ebola has gripped many lawmakers in the U.S.. In one high-profile case, MSF nurse Kaci Hickox was forced into quarantine over the weekend after landing in New Jersey from Sierra Leone, despite twice testing negative for the disease. After Hickox returned home to Fort Kent, Maine on Wednesday, Governor Paul LePage sought legal authority to impose a full 21-day quarantine on her.

These kinds of responses are causing "rising anxiety and confusion" among staff over what they may face when they leave the field, Delaunay told Reuters. Many have considered delaying their return home, she said, while others have been deterred from going back on assignment in West Africa, where Ebola has killed nearly 5,000 people in Guinea, Sierra Leone and Liberia.

MSF missions typically begin and end in Brussels, Belgium. Some MSF workers are opting to remain there after completing their assignments for 21 days—the incubation period for Ebola—so that they are not forced into quarantine when they return home, Delaunay said. She added that others "are being discouraged by their families from returning to the field."

New Jersey Governor Chris Christie and New York Governor Andrew Cuomo both announced strict screening regulations at airports last Friday, including mandatory quarantines for health care workers who had been treating Ebola patients in West Africa. MSF said the move was "not grounded on scientific evidence and could undermine efforts to curb the epidemic at its source." The aid group has an internal policy that requires workers not to return to their jobs for 21 days after finishing an assignment, and pays them wages to make up for that time.

Delaunay told Reuters that non-American workers on the ground in West Africa have also started to fear that other countries may take cues from the U.S. and impose their own mandatory quarantines on people returning from MSF assignments.

In the last week, three other MSF workers have returned to the U.S. from treating Ebola patients in West Africa and have not been forced into isolation, a spokesperson for the group said.

Armand Sprecher, an MSF doctor in Brussels who recently completed an assignment in Liberia, wrote in the New Republic that if workers are "discouraged by the prospect of three weeks of near total isolation on their return, we may lose the services of many good people."