Use of dogs trained to search for wild boar carcasses in passive surveillance as the most effective tool to control the spread of African swine fever in Poland

Abstract

The most effective proactive measures to combat the African swine fever virus (ASFV) and mitigate the financial losses associated with its spread to pig farms is to minimise its transmission within the wild boar population. The aim of the study was to compare traditional human ground search with alternative methods using specially trained detection dogs, hunting dogs and drones in locating and removing wild boar carcasses as the main source of ASFV infection. Most of wild boar carcasses 397 out of 400 (99.2 %) were found by the trained search dogs, while other 3 were located using hunting dogs. Also, the efficiency of carcass retrieval with hunting dogs was much lower than with trained dogs with 0.002 versus 2.08 ASFV RT-PCR positive WB carcasses found per search. Searches with drones, humans or mixed method were found unsuccessful. The search efficiency using dogs trained for this purpose was on average more than two and a half times higher than the values determined by the EFSA ASF exit strategy developed using the wild boar approach. The carcass retrieval by search dogs was associated with ASF seasonality in wild boar in the central Europe, however, was not affected by the harsher conditions of winter months. This is particularly important due to the ASFV ability to survive in low tempera- tures. The study revealed also local variation in the sampling efforts which could have affected effectivity of ASF passive surveillance. To our knowledge, the presented research is the first attempt to evaluate the use of dogs to locate wild boar carcasses as a key element of passive surveillance in ASF control.