Initial genetic analyses of African swine fever viruses in Catalonia suggest that a laboratory leak is ‘highly unlikely’

What is clear is that the virus circulating is different from those generally circulating in other European Union countries, and it remains to be seen whether, as expected, this different virus also has different epidemiological characteristics. For example, if it has many modifications, many mutations, this may affect its transmissibility and, therefore, the length of time that infected wild boars can remain infectious. This may affect the dynamics of the outbreak in the sense that all European protocols for action against African swine fever are designed for the highly pathogenic variants that generally circulate in other affected countries in the Union.

In other words, if we have a different virus here, we may have to adapt to this new circumstance in some way. That is the most important thing, regardless of the origin of the virus.

Given the results of this sequencing, which still seems to be missing some other viruses to be analysed, and it is possible that more information will emerge over time, there is currently nothing conclusive about the origin. The possibility of an origin via the introduction of a contaminated product, food, or meat product remains open, and I would not completely rule out the possible origin of the laboratory either.

We will have to wait and see what conclusions other analyses that are being carried out reach. I insist, the origin is not as important as the fact that we are facing the problem and adapting to this somewhat novel situation of a different virus.

These studies would show that the outbreak found in wild boars does not come from any of the viruses handled at CReSA at the time when the infectious outbreak of African swine fever was detected and, therefore, can be completely ruled out.

The fact that the virus found in wild boars has not been described until now is not surprising, and we should not think that a new virus has emerged, but simply that there are many strains of African swine fever circulating around the world that are not included in the databases consulted because they have not actually been incorporated into those databases.

There are many strains circulating in Europe and Asia, and traces of these strains in food may have reached the place where these infected wild boars are found, because the world is global, people move around a lot and can transport contaminated food. For example, in Ukraine, the different viral strains that are currently evolving there freely are not being incorporated into the database. It is not so unusual to think that it may be a strain that is circulating but has not been included in the databases.

It should also be borne in mind that one of the things that the African swine fever virus tends to do is to evolve in wildlife to adapt to the host it is infecting at the time — in this case wild boars — and not to kill the animal. These are strains that attenuate their original virulence so that infected animals do not die. I am not at all surprised that the combination of these scenarios may have caused this outbreak. Unfortunately, none of the viruses we know of lately are immutable pathogens, but rather adapt their genetic material to the conditions that best suit them.

The result is good news for many reasons. A highly secure and trusted facility has been called into question, and, incidentally, so have the professionals. The Generalitat and the European Commission have all said that there was no breach in the security protocols that would justify an escape after inspecting the facility.