Monitoring of chronic wasting disease in deer in Poland between 2018 and 2020

Chronic wasting disease (CWD) is a lethal infectious neurodegenerative disease, the etiological factor of which is the infectious prion protein. Infections affect animals of the deer family (Cervidae). The aim of the study was to analyze the results of monitoring for the presence of CWD in the years 2018-2020 carried out by the Veterinary Inspectorate in Poland. The aim of the monitoring program in force in 2018-2020 was to assess the epizootic situation of CWD in Poland and other European countries, where no cases of the disease have been detected so far. Six species of deer were monitored: Eurasian tundra reindeer, Finnish forest reindeer, roe deer, elk, red deer, and white-tailed deer. Samples for the study were collected by veterinarians and trained persons and came from a latch within the medulla, retropharyngeal lymph nodes, tonsils, or other lymph nodes in the head. During the three-year CWD monitoring in Poland, a total of 3541 samples from animals from the deer family were examined. With regard to farmed and captive animals, the samples came from 225 red deer and 1 clump, and in the case of wild animals, the study included 192 elk, 2703 roe deer, and 420 red deer. In 2018, 1141 animals were tested: 23 farm-kept noble deer and 42 elk, 886 roe deer, and 190 wild-living noble deer. In 2019, the monitoring covered 1246 animals: 115 red deer and 1 female elk were farm animals, and the remaining 83 elk, 902 roe deer, and 145 red deer were free-living. In the last year of the program, 1154 animals were tested: 87 farmed red deer and 67 wild elk, 915 roe deer, and 85 wild deer. During the monitoring period, no cases of chronic wasting disease (CWD) of cervids were detected in Poland. The program officially ended at the end of December 2020 and was not extended because of the absence of CWD-positive results.