Marburg: Continued linear growth?

According to the numbers released by the WHO on 18 May, the number of Marburg cases continues to grow linearily. The current rate is at around 3 new cases per day, and has been around that number since the beginning of April. On the one hand this means that the outbreak is not completely out of control since the numbers aren't growing exponentially, but on the other hand, the numbers continue to grow at a steady rate, meaning the outbreak isn't completely under control either. The minimal fatality rate is still above 90%.