TY - JOUR
KW - absorption
KW - carcass detection
KW - aircraft mounted thermal imagers
KW - drone
KW - infrared
AU - U Hohmann
AU - M Kronenberg
AU - M Scherschlicht
AU - F Schönfeld
AB - The removal of wild boar carcasses is one of the first important countermeasures after an ASF outbreak. Thermal imagers that visualise body temperature are already in use for selective carcass detection. In addition to carrion-specific infrared radiation (IR-radiation) derived from natural body temperature or decay heating, non-carrion specific heat sources such as the absorption of sunlight, limit detection selectivity. To understand the influence of different heat sources on the IR-radiation phenology of carcasses better, we monitored the internal temperature of nine culled wild boar (Sus scrofa) during decomposition using dummies as a control. Culling took place between June and November and the objects were placed in fenced-off areas. Some of them were exposed to direct sunlight throughout, while others remained in the shade. For detection, we used both stationary and helicopter mounted thermal imagers. As expected, all culled boar had cooled down approximately two days after death. In summer, in culled boar that were placed at ambient temperatures above 10 °C, decay-heating started after 3–7 days and lasted up to four weeks. In the carcasses that were exposed to direct sunlight, absorption had a similar effect on IR-radiation as is normally observed from internal heating. In boar culled during November–December at an ambient temperature below 10 °C, we found no signs of decomposition or decay-heating. Solar absorption was the main source of IR-radiation after algor mortis. We therefore conclude that thermal imaging will be less efficient for detecting carcasses during colder seasons (Ø <10 °C; November–March) and at other times of the year on sunny days and the subsequent nights following such days. Considering the highlighted challenges relating to the detection of wild boar carcasses using IR-radiation, and the fact that moribund boar prefer places with IR-shielding vegetation to die, the continued reliance on a ground search approach for detecting infected carrion is still inevitable at present.
BT - Berliner und Münchener Tierärztliche Wochenschrift
CY - Hannover
DA - 08/2021
DO - 10.2376/1439-0299-2020-46
LA - English
N2 - The removal of wild boar carcasses is one of the first important countermeasures after an ASF outbreak. Thermal imagers that visualise body temperature are already in use for selective carcass detection. In addition to carrion-specific infrared radiation (IR-radiation) derived from natural body temperature or decay heating, non-carrion specific heat sources such as the absorption of sunlight, limit detection selectivity. To understand the influence of different heat sources on the IR-radiation phenology of carcasses better, we monitored the internal temperature of nine culled wild boar (Sus scrofa) during decomposition using dummies as a control. Culling took place between June and November and the objects were placed in fenced-off areas. Some of them were exposed to direct sunlight throughout, while others remained in the shade. For detection, we used both stationary and helicopter mounted thermal imagers. As expected, all culled boar had cooled down approximately two days after death. In summer, in culled boar that were placed at ambient temperatures above 10 °C, decay-heating started after 3–7 days and lasted up to four weeks. In the carcasses that were exposed to direct sunlight, absorption had a similar effect on IR-radiation as is normally observed from internal heating. In boar culled during November–December at an ambient temperature below 10 °C, we found no signs of decomposition or decay-heating. Solar absorption was the main source of IR-radiation after algor mortis. We therefore conclude that thermal imaging will be less efficient for detecting carcasses during colder seasons (Ø <10 °C; November–March) and at other times of the year on sunny days and the subsequent nights following such days. Considering the highlighted challenges relating to the detection of wild boar carcasses using IR-radiation, and the fact that moribund boar prefer places with IR-shielding vegetation to die, the continued reliance on a ground search approach for detecting infected carrion is still inevitable at present.
PB - Schlütersche Fachmedien GmbH
PP - Hannover
PY - 2021
SP - 1
EP - 14
T1 - The possibilities and limitations of thermal imaging to detect wild boar (Sus scrofa) carcasses as a strategy for managing African Swine Fever (ASF) outbreaks
T2 - Berliner und Münchener Tierärztliche Wochenschrift
TI - The possibilities and limitations of thermal imaging to detect wild boar (Sus scrofa) carcasses as a strategy for managing African Swine Fever (ASF) outbreaks
TT - ASP-Bekämpfung: Kadaversuche aus der Luft – Möglichkeiten und Einschränkungen
VL - 134
SN - 1439-0299
ER -