# Preemptive Wild Boar Reduction: A Bridge Not Too Far in Effective Response to ASF Threat in a Protected Area Under High Anthropogenic Pressure

## TL;DR

This paper shows how preemptively reducing wild boar populations helped control an African swine fever outbreak in a protected area near a large city.

## Contribution

The study demonstrates that early population reduction measures can effectively limit disease spread in high-risk, human-impacted natural areas.

## Key findings

- The wild boar population in Kampinoski National Park was reduced to its lowest level before the peak of the African swine fever outbreak.
- Early culling likely played a key role in limiting the spread of the disease despite controversy.
- The estimated mortality rate from the disease may have been up to 50% higher than recorded cases.

## Abstract

Protected natural areas near large cities face increasing challenges from human activity and emerging wildlife diseases. This study examines Kampinoski National Park in central Poland to illustrate how African swine fever spread in such an environment between 2017 and 2021. The virus most likely entered the area through wild boars migrating along ecological corridors or accidentally via visitors. Early and intensive efforts—monitoring and population reduction—helped contain the outbreak. In 2018, when ASF reached its peak and 375 infected wild boars were found dead, the wild boar population in the park was already at its lowest level in history due to earlier depopulation measures. Thus, the peak of the disease occurred when the population was at its minimum because of preventive culling. The actual mortality rate may have been even higher. The results highlight that effective action is possible when taken early. In this case, reducing the wild boar population likely helped significantly limit the spread of the disease. This study emphasizes the need for proactive and strong cooperation between different institutions to protect nature in areas exposed to high anthropogenic pressure and the risks of infectious diseases.

In Kampinoski National Park (KNP), located in central Poland near the Warsaw agglomeration, the ASF epidemic lasted five years (2017–2021). The virus likely entered the park via wild boar migrating along a natural ecological corridor or through unintentional transmission by residents and tourists. Between 2014 and 2021, intensive monitoring and wild boar population reduction were implemented. The wild boar population, estimated at 11 individuals/km2 in 2013, began to be reduced from 2014 onward, when ASF was first detected in Poland. In 2018, at the peak of the epidemic, the density of wild boar dropped to about 0.51 individuals/km2—the lowest in the park’s history. Between 2017 and 2021, 408 ASF cases were recorded, mainly in dead wild boar, although age and sex structure analysis suggests that the actual mortality rate could have been up to about 50% higher. The early intervention—culling—which was controversial from the National Park’s perspective, appears to have played a key role in controlling the situation and likely in limiting the epidemic. At the same time, the limited organizational resources of KNP highlighted the need for proactive management and close institutional cooperation in protected areas subject to high anthropogenic pressure.