Wild boar visits to commercial pig farms in southwest England: implications for disease transmission

Abstract

Contact between wild animals and farmed livestock may result in disease transmission with huge financial, welfare and ethical consequences. Conflicts between people and wildlife can also arise when species such as wild boar (Sus scrofa) consume crops or dig up pasture. This is a relatively recent problem in England where wild boar populations have become re-established in the last 20 years following a 500-year absence. The aim of this pilot study was to determine if and how often free-living wild boar visited two commercial pig farms near the Forest of Dean in southwest England. We placed 20 motion-sensitive camera traps at potential entry points to, and trails surrounding, the perimeter of two farmyards housing domestic pigs between August 2019 and February 2021, covering a total of 6030 trap nights. Forty wild boar detections were recorded on one farm spread across 27 nights, with a median (range) of 1 (0 to 7) night of wild boar activity per calendar month. Most of these wild boar detections occurred between ten and twenty metres of housed domestic pigs. No wild boar was detected at the other farm. These results confirm wild boar do visit commercial pig farms, and therefore, there is potential for contact and pathogen exchange between wild boar and domestic pigs. The visitation rates derived from this study could be used to parameterise disease transmission models of pathogens common to domestic pigs and wild boars, such as the African swine fever virus, and subsequently to develop mitigation strategies to reduce unwanted contacts.

Characterizing the domestic-wild bird interface through camera traps in an area at risk for avian influenza introduction in Northern Italy

“…Primarily, the camera-trap monitoring encompassed a limited number of poultry farms and sites, possibly limiting the generalizability of the conclusions to other farm settings. Additionally, the placement of cameras in areas of heightened human activity (e.g., feed silos; chicken manure collection points) resulted in numerous non-relevant triggers, contributing to battery depletion and camera trap failures, thereby reducing the camera trap effort over the study period, a phenomenon documented in other studies as well ( Bacigalupo et al, 2022 ; Engeman et al, 2011 ). Lastly, for a comprehensive grasp of the factors influencing wild bird activity on poultry farms, future research should encompass additional variables such as habitat characteristics and environmental factors, aspects that were not considered in the models presented within this study.…”

A multi-host mechanistic model of African swine fever emergence and control in Romania

“…A transmission rate from wild boar to domestic pigs has been previously estimated for the ASF situation in Poland (21), but it was derived from estimated contact rates between wild boar and domestic pig on free- roaming pig farms in savannah-like habitat in Spain (24). Conversely, contact patterns in England between wild boar and domestic pig farms were estimated at upwards of 7–14 contacts per month (25). Assuming a transmission probability from wild boar to domestic pigs of 0.167 (26), this equates to an expected transmission rate of 1 case every 1.7 to 3.4 weeks, in-line with our own estimates of two villages infected every three weeks by infectious wild boar cells.…”

Evaluation of Antibody Tests for Mycobacterium bovis Infection in Pigs and Deer

“…If, like deer tests, the sensitivity is significantly lower without a skin test, then the ~15% seroprevalence in FoD will be an underestimate of the actual prevalence of infection. Wild boars constitute a potential TB risk for domestic pig herds in endemic areas of England where both co-exist—this is underscored by a recent study [ 21 ] near the Forest of Dean that described the visitations of wild boar to two commercial pig farms. Elsewhere in Europe wild boar are considered to be significant maintenance hosts of M. bovis and a source of infection for cattle [ 12 , 22 , 23 , 24 , 25 ], while in South Africa M. bovis infection in warthogs risks disease spread within and between national parks and wildlife reserves [ 13 ].…”