Sharp drop in African Swine Fever outbreaks in EU offers hope for pig sector recovery

EUROPE – African swine fever (ASF) outbreaks in domestic pigs across the European Union plummeted by 83% in 2024, marking the lowest figures recorded since 2017, according to the European Food Safety Authority’s (EFSA) latest annual epidemiological report.

The number of confirmed outbreaks in domestic pigs fell from 1,929 in 2023 to just 333 in 2024. This substantial decrease is largely attributed to fewer cases in Romania and Croatia. Romania, however, still accounted for a significant 66% of the total, reporting 220 outbreaks.

The drop in outbreaks also coincided with a milestone: for the first time since ASF genotype II entered the EU in 2014, the number of affected Member States declined. 

Fourteen countries reported ASF in 2023, but that number dropped to thirteen in 2024 after Sweden regained ASF-free status, and no new Member State reported infections.

“The decline is encouraging and reflects intensified surveillance and control measures, especially in high-risk areas,” the EFSA noted. “Most outbreaks (78%) occurred in establishments with fewer than 100 pigs.”

Despite the progress, the disease remains entrenched, particularly in Romania, where outbreaks occurred in both small farms and larger industrial operations. 

Notably, six outbreaks were recorded in establishments with over 10,000 pigs, including three in Romania, two in Italy, and one in Poland.

While domestic pig outbreaks declined, ASF remained persistent in wild boar populations. Between 7,000 and 8,000 outbreaks in wild boar were recorded in 2024, a number largely unchanged from previous years. Poland alone reported 30% of these cases.

A concerning development occurred in Germany in June 2024, when ASF was introduced into wild boar populations in the country’s southwest, a significant long-distance translocation event. The virus eventually spilt over into domestic pig populations. 

“Although the cause of this long-distance translocation event remains unknown, genetic analyses indicate an introduction from outside Germany,” the report stated.

Enhanced passive surveillance for early detection

Surveillance efforts have increasingly focused on passive methods, where suspected cases are tested. These accounted for nearly 80% of domestic pig outbreak detections and 70% of wild boar. 

Enhanced passive surveillance, systematic sampling of dead animals, proved especially effective in large farms. In establishments with more than 1,000 pigs, this method identified 68.4% of the outbreaks.

EFSA urged continued reliance on passive surveillance, especially enhanced approaches during high-risk periods.

“The systematic sampling of dead pigs should continue to ensure early detection of the disease,” EFSA scientists recommended.

Seasonal trends persisted. In domestic pigs, over half of all outbreaks were reported between July and September. In wild boar, higher positivity rates from PCR testing were noted during winter in Italy, Hungary, Poland, and Slovakia.

Wild boars continue to harbour disease 

In total, 91.5% of wild boar samples came from hunted animals, though only 0.4% tested positive. Meanwhile, samples from dead wild boar, just 5.2% of total samples, had a 29% positivity rate and were responsible for detecting over 70% of outbreaks in this group.

Despite the reduction in pig outbreaks, the size of restricted surveillance zones remained mostly stable, with a slight increase in the area covered (+1.9%). Italy stood out as the only Member State to experience an increase in outbreak incidence, linked to a cluster in its northern region.

Outside the EU, ASF made its first appearance in Albania and Montenegro. Still, the overall trend mirrored the EU’s: an 83% drop in domestic pig outbreaks and a 30% decline in wild boar cases.

As EFSA continues to collect and analyse ASF data under a mandate from the European Commission, the 2024 figures suggest a cautiously optimistic outlook.

Still, with wild boar acting as persistent reservoirs and occasional long-distance jumps occurring, experts caution that vigilance remains essential to preventing a resurgence.

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