Spatial Clustering by Red Deer and Its Relevance for Management of Chronic Wasting Disease
by Atle Mysterud 1,*OrcID,Isa Nergård Skjelbostad 1,Inger Maren Rivrud 2,Øystein Brekkum 3 andErling L. Meisingset 3
1 Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
2 Norwegian Institute for Nature Research (NINA), Sognsveien 68, NO-0855 Oslo, Norway
3 Department of Forestry and Forestry Resources, Norwegian Institute of Bioeconomy Research, Tingvoll gard, NO-6630 Tingvoll, Norway
* Author to whom correspondence should be addressed. Academic Editor: Rita Tinoco Torres Animals 2021, 11(5), 1272; https://doi.org/10.3390/ani11051272 Received: 7 April 2021 / Revised: 23 April 2021 / Accepted: 26 April 2021 / Published: 28 April 2021
(This article belongs to the Special Issue Wildlife Diseases) View Full-Text Download PDF Browse Figures Citation Export
Simple Summary
Chronic Wasting Disease is a deadly infectious disease affecting cervids that was discovered in Norway in 2016. CWD can transmit through environmental reservoirs and aggregation and spatial clustering of animals may affect transmission. Deer usually forage on scattered forage, but anthropogenic food sources are often concentrated in space, leading to spatial aggregation. We determined what caused red deer to revisit the same locations in the environment, and the extent to which this was caused by anthropogenic food sources. We document that the most visited sites were indeed anthropogenic, which opens potential avenues to disease mitigation.
Abstract
Herbivores like cervids usually graze on widely scattered forage, but anthropogenic food sources may cause spatial revisitation and aggregation, posing a risk for transmission of infectious diseases. In 2016, chronic wasting disease (CWD) was first detected in Norway. A legal regulation to ban supplemental feeding of cervids and to fence stored hay bales was implemented to lower aggregation of cervids. Knowledge of further patterns and causes of spatial revisitation can inform disease management. We used a recently developed revisitation analysis on GPS-positions from 13 red deer (Cervus elaphus) to identify the pattern of spatial clustering, and we visited 185 spatial clusters during winter to identify the causes of clustering. Anthropogenic food sources were found in 11.9% of spatial clusters, which represented 31.0% of the clusters in agricultural fields. Dumping of silage and hay bales were the main anthropogenic food sources (apart from agricultural fields), and unfenced hay bales were available despite the regulation. The probability of the clusters being in agricultural fields was high during winter. It may be necessary to find other ways of disposing of silage and enforcing the requirement of fencing around hay bales to ensure compliance, in particular during winters with deep snow.
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5. Conclusions
Factors causing aggregation on agricultural fields will be easier to manage than those causing aggregation in forest. We found that anthropogenic food sources were linked to agricultural fields or close to forest edge. Knowing more about the cause of aggregation and its anthropogenic sources before a disease outbreak could lead to more rapid and effective mitigation. It is well-known that red deer forage on hay bales if they get access. Finding ways to dispose of silage from livestock farms making it inaccessible to red deer and other cervids appears as the most immediate suggestion from our work. It is also critical with compliance to the measures already implemented. The Norwegian Food Safety Authority required all hay bales in Lærdal to be fenced in from 31st of March 2017 as part of the measures implemented to reduce the risk of CWD transmission. We noted some lack of compliance to this regulation. Assumedly the fences were left open for farmers to get easy access to the hay bales during the day, and farmers informed us that fences were closed the previous winter (2017/18) when deep snow attracted deer to the hay bales. They hence seem to have taken a pragmatic approach using the fences only under conditions when red deer approach them. Therefore, this issue appears to be particularly important during years with a lot of snow. Enforcement of the fencing requirement may be necessary during such periods.
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Keywords: agriculture; chronic wasting disease; hay bales; GPS; Norway; red deer; spatial clustering; wildlife disease
FRIDAY, APRIL 30, 2021
Should Property Evaluations Contain Scrapie, CWD, TSE PRION Environmental Contamination of the land?
***> Confidential!!!!
***> As early as 1992-3 there had been long studies conducted on small pastures containing scrapie infected sheep at the sheep research station associated with the Neuropathogenesis Unit in Edinburgh, Scotland. Whether these are documented...I don't know. But personal recounts both heard and recorded in a daily journal indicate that leaving the pastures free and replacing the topsoil completely at least 2 feet of thickness each year for SEVEN years....and then when very clean (proven scrapie free) sheep were placed on these small pastures.... the new sheep also broke out with scrapie and passed it to offspring. I am not sure that TSE contaminated ground could ever be free of the agent!! A very frightening revelation!!!
---end personal email---end...tss
FRIDAY, APRIL 23, 2021
Consultation: Draft VKM order on zoonotic potential in scrapie Singeltary Submission
terry
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