Since the corona crisis, there has been a real fear of crazy viruses. Rightly so. According to new research, there are four types of viruses that are becoming more dangerous at “an exponential rate.” If things continue at this rate, these diseases will together kill twelve times as many people by 2050 as they do now.
In general, epidemics due to viruses originating from animals are now much more common and serious than before. Researchers saw a rapid increase of four types of infections that have jumped from animals to humans: the filoviruses, such as the life-threatening Ebola and Marburg, SARS coronavirus 1, the Nipah virus and the Machupo virus. Overall, there was a pattern of larger and more frequent epidemics, according to an analysis of sixty years of virus outbreak data. And those outbreaks are also much more deadly, the scientists warn.
Dispersal over greater distances
The problem is that the viruses spread more easily over large distances. This is partly due to climate change and changed land use, which results from greater population density and increased mobility, the researchers explain. An epidemic is usually caused by a virus that has jumped from an animal to a human, a so-called zoonosis.
It is clear that zoonotic diseases are becoming more common, but it has been difficult to assess what this means for the future of public health worldwide, as there is little historical data on the annual frequency and severity of such outbreaks, the researchers said. To solve this, they looked at their own extensive epidemiological database, hoping to discover trends in zoonotic virus outbreaks that might reveal what we can expect in the coming decades.
Major danger to health and society
The database used included a wide range of official sources, including World Health Organization (WHO) reports on viruses, outbreaks caused by a virus that killed more than 50 people, and historically significant virus outbreaks such as the 1918 and 1957 flu pandemics.
The researchers focused on the filoviruses, coronaviruses, Nipah virus and Machupo virus that cause severe acute viral hemorrhagic fever. They chose these viruses precisely because they can pose such a great threat to public health, but also to economic and political stability. All told, they looked at 3,150 virus outbreaks and epidemics between 1963 and 2019. In doing so, they hoped to discover trends in the number of outbreaks and associated deaths caused by these viruses.
More and more deaths
Ultimately, they found 75 outbreaks of a virus originating from animals in 24 countries during this period. More than 17,230 people were killed, of whom more than 15,700 died during 40 outbreaks of filoviruses, mainly in Africa. And the worst: the number of zoonoses and the number of deaths resulting from the diseases increased annually by 5 and 9 percent respectively between 1963 and 2019, which does not include the corona pandemic.
“If this annual increase continues, we expect the analyzed viruses to cause four times as many outbreaks and twelve times as many deaths in 2050, compared to 2020,” the researchers estimate.
Tip of the iceberg
And that’s just the tip of the iceberg. After all, only four types of viruses were looked at and extremely strict criteria were used for what counted as an outbreak. Moreover, the worst of all, Covid-19, is not even included.
Yet this was enough to show that we have a lot to fear from those zoonoses. “Our review of the historical evidence shows that the series of recent epidemics caused by zoonoses is not an anomaly or a random cluster, but a multi-decade trend in which such epidemics are not only larger but also more common,” the researchers said .
Action needed
“The perfect package of measures to be better prepared and more resistant to epidemics worldwide is not yet known. However, what is clear from the historical trends is that immediate action is needed to address a greater and growing risk to public health,” it concludes.
