Foreign aid, effectively targeted, is no bad thing and indeed has the potential to save, or even make, money in the long-term.
This particular story shows why it was, and still is, so important to tackle Ebola at the source -- Sierra Leone's own health system was woefully inadequate to deal with the outbreak, meaning that it grew far larger than it might have in a country such as, say, Nigeria, where the health system was able to swing into action and restrict the number of cases to 20 or so, as opposed to 10,000 and growing.
If we're going to give money out in foreign aid we should be careful to ensure that it actually goes to the places it's meant to go rather than being lost due to corruption, but equally we shouldn't let the risks of corruption discourage us from giving aid either. It is vital, not just for the people it's meant to help directly, but also for the country through a whole range of knock-on effects.