At a Memphis roundtable to discuss Shelby County's preparedness for infections diseases, Lamar Alexander expressed concern with President Barack Obama's plan to fight Ebola.

Alexander said the choice of a a former aide to Vice President Joe Biden as Ebola czar means that the national fight against the fearful disease won't be accountable to Congress, adding that a czar was "not what I had in mind."

Alexander prefers a cabinet member accountable to Congress, he said in a tweet.

When it comes to Tennessee's readiness to fight Ebola, Alexander said the state has "a terrific health department — one example is the heroic response to the recent fungal meningitis outbreak."

He also defended his remarks on Sept. 15 that Ebola was as serious as ISIS, the terrorist group, rebutting critics who said at the time that he had made an overstatement.

Alexander, a Republican, is locked in a heated election with Democrat Gordon Ball. The two have attacked each other repeatedly, upping the ante at a Thursday debate in which Alexander linked Ball to Obama, and Ball attacked Alexander as too moderate, and part of Washington's gridlock.