Francesco Feliziani: "The presence of African swine fever in imported meat products is a ticking time bomb."

BarcelonaItaly has been battling African swine fever (ASF) since January 2022. There, the pathogen is active in wild boar and has affected several domestic farms. To understand how the virus spreads, a group of Italian researchers from the Experimental Zooprophylactic Institute of Umbria and Marche (IZSUM) analyzed the illegal domestic trade in wild boar and meat products seized during inspections for lack of labeling or import irregularities. The report, published at the end of November, made a surprising finding: the virus was detected in one out of every four samples analyzed among the illegally imported products. We spoke with Francesco Feliziani, co-author of the report and director of IZUM.

The report concludes that one in four samples obtained through irregular markets tested positive for ASF. These are very high results. How can this be explained?

— Yes, undoubtedly, these are very high results. However, it's important to clarify that we detected the DNA, but without finding the active virus; therefore, it's not infectious.

What is the most important conclusion that can be drawn?

— The presence of the virus in imported meat products is a ticking time bomb. These products can end up coming into contact with wild boar or pigs, and from there the virus can be reintroduced into livestock farms. Wild boar act as a reservoir for the virus, capable of transmitting it over very long distances.

Is this how the virus entered Italy?

— We don't know for sure, but the human factor was key. It entered actively, probably through waste, garbage, or contaminated food.

What kind of food are we talking about?

— It's difficult to answer this question because we don't have definitive proof. But we can consider processed meats, meat scraps brought in by tourists or foreign workers, or food from infected areas that enters the country informally.

According to reports published by theEuropean Veterinary Emergency Team (EUVET)In Catalonia, a new variant of the virus has been detected and described as variant 29. Its distinguishing feature is a 9.8 kB deletion in the MGF505 gene. How does this type of mutation occur?

— This virus has a very large and stable genome, so mutations are usually small and infrequent. They occur during viral replication—the pathogen multiplies, making copies of itself—but not as frequently as in other RNA viruses, such as COVID-19. This is a transcription error, but not a common one; it's a very slow and exceptional process.

This would suggest that it's been circulating for some time. Does this rule out the possibility that it came from a laboratory?

— It is virtually impossible that this mutation occurred in a laboratory. We only have a limited number of sequences, so it likely derives from a natural mutation, although we don't know when or where it occurred. We are not well acquainted with the sequences circulating in Ukraine, Belarus, Russia, Romania, and Poland, which makes a natural origin more probable than laboratory manipulation.

Could the virus variant detected in Catalonia match the DNA identified in any of its samples?

— It's possible, but not certain. It could be a mutation not yet described. It could be compared with our samples because we have published our sequences. However, we don't foresee this at the moment because we have other priorities. And comparing the genetic code is very complicated because it's so large. The ASF virus has the largest DNA genome of any virus infecting animals, with more than 150 genes, many of them unknown. Its genetic complexity, with repeated regions, duplicated genes, and structural variations, makes accurate sequencing difficult.

How did this variant arrive in Catalonia?

— The entry routes are always the same and are linked to human activity: contaminated food, waste, and refuse. Transmission through a live animal cannot be completely ruled out, but it is not the most likely scenario.

Italy has been living with swine fever for many years. What lessons can Catalonia learn?

— We have been fighting this disease for many years. We have had good results, but we still have a large cluster in the north of the country. It requires significant resources, but eradicating the virus is essential, because otherwise, the pig industry cannot survive. The key is to apply the measures stipulated by European regulations with great precision. It is crucial to act quickly: the sooner the population of sick animals is isolated, the greater the chances of eliminating the virus. The basis of control is separating infected animals from healthy ones with an effective barrier. If the virus persists for too long, the entire pig production sector will face a crisis.

How to combat the illegal domestic trade in wild boar meat within the EU?

— Europe classifies the risk of virus spread based on the presence of infected animals, and containment measures are applied accordingly. But infection can also easily spread through everyday objects, such as a sandwich brought from Eastern Europe, which is more likely than a laboratory leak. It's important to note that in some areas, when an infected pig dies, it is consumed out of economic necessity, facilitating the virus's spread. Since there is no cure or vaccine, prevention is essential. We must implement a scorched-earth policy around the virus and disinfect any trace of it until it is gone.