10/05/2016 08:40 BST | Updated 09/05/2017 06:12 BST

Emerging Viruses: Preparing for the Unknown

It is now evident that a lethal combination of inaction and mistrust was the reason the first case in the West Africa Ebola epidemic sparked the largest outbreak ever recorded. The infection of a two year old boy in rural Guinea became the index case in what was described at the time by many healthcare professionals and politicians as the biggest public health emergency the world has faced since HIV first surfaced in the mid-1980s.

The outbreak of Ebola virus in West Africa, which claimed over seven times more lives than all previous outbreaks combined, is officially over. However, due to our better understanding of the virus, especially how it can persist in tucked away corners of the human's body, means that the countries at the epicentre of the outbreak are still in a state of heightened awareness. Routine testing for Ebola is ongoing with "flare-ups", caused by persistent carriers transmitting the virus to others, a real concern.

It is worth noting that the impact of the outbreak was not just restricted to public health consequences. There are also social and economic issues, such as stigma associated with surviving infection and an estimated USD$2.2 billion lost in economic growth during 2015 across the three countries where the virus took hold.

However, one of the most positive messages to take from the Ebola outbreak in West Africa is the dedication and courage of the staff who worked in the many Ebola treatment centres in Guinea, Sierra Leone and Liberia. At the end of 2014, when the number of cases was increasing almost exponentially, and some scientists were forecasting it could rise to over one million by 2015, staff on the front line worked tirelessly in challenging conditions to ensure only a fraction of the predicted number became infected. All of this was achieved using basic intervention strategies that had been employed to contain previous outbreaks of Ebola since the virus was first identified in the 1970s and with the knowledge that their work was putting them at great risk. Indeed, staff working in Ebola treatment centres were 20-30 times more likely to become infected than people in the general population.

While this highlights existing control strategies could still be effective, there are many lessons to be learnt and changes to be made that will hopefully stop an outbreak occurring on this scale again. These include:

1. Better integration of regional, national and international public health bodies that undertake surveillance for emerging virus threats.

2. The healthcare infrastructures in areas likely to be at the centre of future outbreaks must be improved to enable effective care, treatment and diagnosis.

3. It is crucial that leaders, healthcare professionals and whole communities are made aware of the risk that emerging infections pose.

4. The scientific and clinical communities need to be better prepared. Technology platforms for tests capable of diagnosing infected individuals faster, effective treatments for people unfortunate enough to become infected, and vaccines to prevent new cases need to be advanced to early stage clinical trials. It will then be possible to deploy them much earlier in an outbreak.

The funding to undertake this remedial work has previously been hard to come by but, given the impact of Ebola virus and now Zika virus in the Americas, there have been commitments by governments and funding agencies to address this shortfall. This will hopefully go some way towards the estimated USD$4.5 billion annual investment in research and development needed to mitigate the global threat posed by emerging infections.

This funding will help put in place a framework that would hopefully enable a more robust response. Further to the four points raised above, more development of networks is also needed to undertake active surveillance and monitoring. There is also a need to expand the number of clinicians and scientists with the skills to deal with emerging virus outbreaks. Finally, given we already know about some of the pathogens that pose a threat (MERS coronavirus, Marburg virus etc.), development of specific interventions to control these infections can and should be prioritised.

Despite all of this, it is important to understand that emerging viruses will be a constant threat of our time, as an expanding global population lives in closer proximity to the natural reservoirs of many of these viruses. Our society is also much more mobile, and this further contributes to the rapid spread of infections across the globe.

Unfortunately, the explosion in cases of Zika virus in Central and Southern America that started in 2015 followed too soon after Ebola. What's more, the framework to limit the global impact of emerging infections was not in place. We can hope that the basic interventions being employed by the staff working on the front line in the Americas to tackle Zika virus are as effective as those employed in West Africa. However, the fact that the virus is primarily spread by mosquitoes changes the game plan compared to the Ebola crisis.

We will always face the threat from emerging viruses as they cannot be eradicated from their natural reservoirs. They also readily mutate which can play a part in the rise of new infections and nullify the existing immune response in the host. As scientists and healthcare professionals, it is essential that we now take what we have learnt over the last 28 months and implement improvements to limit the impact of the next outbreak before it strikes and finds us unprepared.