"UnitedHealthcare Responds to Ebola Concerns ... The health and wellbeing of our members is a top priority ... Diagnostic testing and associated care will be covered in accordance with the terms of your health plan."
Notice that they're neither confirming nor denying that your plan will cover Ebola-related expenses. And of course, UHC offers many different plans - individual and group - so coverage is likely to differ among them. So some plans may include that endemic disease exclusion, some (most? all?) may not. The only way to know for sure is to check your SPD (Summary Plan Document) for the list of exclusions.
You might also call the customer service hotline, but be warned that you're then taking the word of an anonymous CSR who may (or may not) know what you're talking about.