Cisse and Tiote have been representing Ivory Coast and Senegal respectively during Africa Cup of Nations qualifiers this week.
"We'd be naive not to have concerns," he said.
"We have a strategy for when they return and making sure they and their families are taken care of.
"They're essential to us and our doctor has looked into the problems that might arise and also protection for them and to make sure we do our very best to help them."
There has been a suggestion that January's finals in Morocco could be postponed should the virus not be contained.
And Pardew added: "That's something that will play out as we go along. That kind of decision is a big, big one and I'm sure the countries will make that rather than club managers.
"It's something to be concerned about and we have to be on our guard."
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