At this moment, in addition to combating Zika in the United States and polio in Nigeria and Pakistan, we're putting out the last embers of Ebola in West Africa, stomping out cholera in Tanzania and Kenya, and fighting yellow fever in Angola. We're keeping vigilant for the re-emergence of H5N1 influenza and Middle East respiratory syndrome, and monitoring chikungunya, dengue, monkeypox, Lassa fever, measles…the list goes on.

It's a lot to do. And these are just the diseases we know about. The brutal fact is that there are diseases we haven't discovered yet. They're out there, waiting to expose the cracks in our systems – to find the places where we aren't watching, the areas where we aren't prepared. And we can't know the potential danger.

Finding – and filling – the gaps

The fact is, if you leave an opening – any opening – disease will find it. This is why it's critical to have strong public health systems in place before emergencies happen. We can do more to recognize what causes outbreaks, respond to them faster, and bring them under control more effectively.