Embattled Center for Disease Control Director Dr. Thomas Frieden told lawmakers on Thursday that Ebola is not a significant threat to America. 

“We remain confident that Ebola is not a significant public health threat to the United States,” Frieden said in written testimony before his Thursday appearance before the House Energy and Commerce Subcommittee on Oversight and Investigations. “It is not transmitted easily, and it does not spread from people who are not ill, and cultural norms that contribute to the spread of the disease in Africa–such as burial customs and inadequate public health measures–are not a factor in the United States.” 

Despite Frieden’s assurance that Ebola remains an insignificant public health threat, the CDC director admitted he and the CDC “do not yet know exactly how these transmissions occurred.” 

Reps. Tom Marino (R-PA) and Pete Sessions (R-TX) have called on Frieden to resign in the wake of a second Ebola patient and the CDC’s decision to tell the victim she was fine to fly in an airplane despite having a mild fever.