Maine Education Commissioner Jim Rier published an open letter to school officials and parents Thursday to dispel fears about Ebola, after a western Maine school district put a teacher on leave last week because she had been to Dallas, where the nation’s first Ebola patient died.

Spokeswoman Samantha Warren said the Maine Department of Education has received numerous calls about Ebola since the virus killed a man in Texas and infected two nurses this month in a Dallas hospital.

The Ebola virus cannot be transmitted through the air; it can spread only through contact with bodily fluids that contain the virus, according to the U.S. Centers for Disease Control and Prevention.

Nevertheless, a teacher at Strong Elementary School was put on a 21-day paid leave last week after parents raised concerns that the teacher had attended an educational conference in Dallas, about 10 miles from Texas Health Presbyterian Hospital. About 30 Maine educators attended the Smarter Balanced Assessment Consortium in Dallas, according to conference organizers.

Maine public health experts told the Portland Press Herald last week that there was no risk of contracting Ebola from conference attendees.

Warren said no other teachers in Maine were placed on leave, but many school officials have called the department with questions and concerns.

“Enough districts have been calling that we thought this would be the most efficient and effective way to get the information out,” said Warren.

Rier, in his letter, reiterated that Ebola can be transmitted only through bodily fluids and that there are no Maine cases.

“While it is important (to) always take precautions to protect ourselves and our students from infectious diseases, it is also important to make sure communications by officials and the media increase awareness rather than anxiety,” Rier wrote.

Nearly 5,000 people have died from Ebola in West Africa, but the disease has not gained a foothold in the United States. Public health officials say Ebola is not likely to spread in the U.S. because of a stronger health infrastructure here than in West African countries.

But news coverage has raised concerns. In Mississippi, parents pulled middle school students from classes after learning that the school’s principal had attended a funeral in Zambia, thousands of miles from the Ebola outbreak.

Last week, Freeport Middle School temporarily isolated a student after she incorrectly told a classmate that her father was being tested for Ebola.

Also last week, someone was held for observation at Maine Medical Center in Portland because the person had a fever and had traveled to a “region of concern,” but the patient was found not to have the disease, according to the Maine CDC.