There are about 200,000 Africans from countries hosting the deadly Ebola virus who hold temporary visas to visit the United States, greatly raising the stakes it could spread to America, according to a group following the immigration issue.

“Based on State Department nonimmigrant visa issuance statistics, I estimate that there are about 5,000 people in Guinea, 5,000 people in Sierra Leone, and 3,500 people in Liberia who possess visas to come to the United States today,” said Jessica M. Vaughan, director of policy studies at the Center for Immigration Studies.