Managing African Swine Fever: Assessing the Potential of Camera Traps in Monitoring Wild Boar Occupancy Trends in Infected and Non-infected Zones, Using Spatio-Temporal Statistical Models

Abstract

The recent spreading of African swine fever (ASF) over the Eurasian continent has been acknowledged as a serious economic threat for the pork industry. Consequently, an extensive body of research focuses on the epidemiology and control of ASF. Nevertheless, little information is available on the combined effect of ASF and ASF-related control measures on wild boar (Sus scrofa) population abundances. This is crucial information given the role of the remaining wild boar that act as an important reservoir of the disease. Given the high potential of camera traps as a non-invasive method for ungulate trend estimation, we assess the effectiveness of ASF control measures using a camera trap network. In this study, we focus on a major ASF outbreak in 2018–2020 in the South of Belgium. This outbreak elicited a strong management response, both in terms of fencing off a large infected zone as well as an intensive culling regime. We apply a Bayesian multi-season site-occupancy model to wild boar detection/non-detection data. Our results show that (1) occupancy rates at the onset of our monitoring period reflect the ASF infection status; (2) ASF-induced mortality and culling efforts jointly lead to decreased occupancy over time; and (3) the estimated mean total extinction rate ranges between 22.44 and 91.35%, depending on the ASF infection status. Together, these results confirm the effectiveness of ASF control measures implemented in Wallonia (Belgium), which has regained its disease-free status in December 2020, as well as the usefulness of a camera trap network to monitor these effects.

Management of a Focal Introduction of ASF Virus in Wild Boar: The Belgian Experience

“…Both fencing and depopulating have played a significant role in the extinction rate of wild boar according to a contemporary camera trap-based study aiming to compare the occupancy of wild boar in time and space in a representative part of the ASF management zone from March 2019 till June 2020 [ 32 ].…”

Examining the International Bushmeat Traffic in Belgium: A Threat to Conservation and Public Health

“…Diseases of concern carried by these products may include foot and mouth disease, African swine fever, classical swine fever and swine vesicular disease [26,32]. The major African swine fever outbreak in Belgium between 2018 and 2020 highlights the severity of such an incursion [5]. Bushmeat could potentially also be the source of new pathogens different from those already known in livestock.…”

Automated Detection and Counting of Wild Boar in Camera Trap Images

“…Morelle et al [16] used camera trap data to study wild boar density and abundance following an ASF outbreak in Poland. Bollen et al [17] investigated the use of camera traps to monitor wild boar densities in ASF-affected and non-affected areas in Belgium.…”