Risk-based surveillance of chronic wasting disease in semi-domestic reindeer

Viljugrein, Hildegunn; Hopp, Petter; Benestad, Sylvie L.; Våge, Jørn; Mysterud, Atle

doi:10.1016/j.prevetmed.2021.105497

Cited by 5 publications

(10 citation statements)

References 73 publications

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Section: Assessment/resultsmentioning

confidence: 99%

“…Nordfjella is bordered in the north‐east by the semi‐domestic reindeer population of Filefjell with about 3,000 individuals (Viljugrein et al., 2021 ). A (scenario tree) model for this specific management system was developed using three risk categories: sample target group, demographic group, and deviations in behaviour or physical appearance (Viljugrein et al., 2021 ). The model makes the assumption that since herders stress the animals in penned areas during slaughtering in late fall, animals with deviant behaviour or physical appearance will be removed.…”

Section: Assessment/resultsmentioning

confidence: 99%

“…This difference should be taken into account both when designing the surveillance and when assessing the results, through assigning different weights to samples from different target groups. This approach, assigning different values to different surveillance streams has been used for TSE surveillance in bovines both at EU‐ and WOAH‐level (Prattley et al., 2007 ) as well as for CWD in North America (Cullingham et al., 2011 ; Jennelle et al., 2018 ; Smolko et al., 2021 ) and Norway (Viljugrein et al., 2021 ). Based on available data, a 1:10 weight should be used, assigning 1 to HSHC and 10 to high‐risk animals (animals with clinical signs of CWD, fallen or otherwise diseased).…”

Section: Assessment/resultsmentioning

confidence: 99%

See 2 more Smart Citations

Monitoring of chronic wasting disease (CWD) (IV)

Koutsoumanis¹,

Allende²,

Álvarez‐Ordóñez³

et al. 2023

EFS2

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The European Commission requested an analysis of the Chronic Wasting Disease (CWD) monitoring programme in Norway, Sweden, Finland, Iceland, Estonia, Latvia, Lithuania and Poland (9 January 2017–28 February 2022). Thirteen cases were detected in reindeer, 15 in moose and 3 in red deer. They showed two phenotypes, distinguished by the presence or absence of detectable disease‐associated normal cellular prion protein (PrP) in lymphoreticular tissues. CWD was detected for the first time in Finland, Sweden and in other areas of Norway. In countries where the disease was not detected, the evidence was insufficient to rule out its presence altogether. Where cases were detected, the prevalence was below 1%. The data also suggest that the high‐risk target groups for surveillance should be revised, and ‘road kill’ removed. Data show that, in addition to differences in age and sex, there are differences in the prion protein gene (PRNP) genotypes between positive and negative wild reindeer. A stepwise framework has been proposed with expanded minimum background surveillance to be implemented in European countries with relevant cervid species. Additional surveillance may include ad hoc surveys for four different objectives, specific to countries with/without cases, focusing on parallel testing of obex and lymph nodes from adult cervids in high‐risk target groups, sustained over time, using sampling units and a data‐driven design prevalence. Criteria for assessing the probability of CWD presence have been outlined, based on the definition of the geographical area, an annual assessment of risk of introduction, sustained minimum background surveillance, training and engagement of stakeholders and a surveillance programme based on data‐driven parameters. All positive cases should be genotyped. Sample sizes for negative samples have been proposed to detect and estimate the frequency of PRNP polymorphisms. Double‐strand sequencing of the entire PRNP open reading frame should be undertaken for all selected samples, with data collated in a centralised collection system at EU level.

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Section: Assessment/resultsmentioning

confidence: 99%

Section: Assessment/resultsmentioning

confidence: 99%

Section: Assessment/resultsmentioning

confidence: 99%

See 1 more Smart Citation

Monitoring of chronic wasting disease (CWD) (IV)

Koutsoumanis¹,

Allende²,

Álvarez‐Ordóñez³

et al. 2023

EFS2

Self Cite

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“…In reindeer populations without information about sex and age composition, we assumed a demographic composition similar to that of the population surveillance areas. Future developments may also include the genetic composition of populations linked to the prion protein gene, PRNP , affecting susceptibility to CWD among reindeer (Viljugrein et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

“…For the smaller populations, only rough population estimates were available (VKM et al, 2021). We assumed a similar demographic composition to the areas surveyed.…”

Section: After Cwd Detectionmentioning

confidence: 99%

Challenges and opportunities using hunters to monitor chronic wasting disease among wild reindeer in the digital era

Mysterud

Viljugrein

Hopp

et al. 2023

Ecol Sol and Evidence

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1. Surveillance of wildlife diseases poses considerable logistical challenges compared to that of humans or livestock. Citizen science can enable broader coverage, but building an efficient disease monitoring system that relies on hunters is challenging. Chronic wasting disease (CWD) is a lethal and infectious prion disease of cervids. Improving surveillance is important with the detection of CWD in wild reindeer (Rangifer tarandus) in Norway.2. This study describes the components of an efficient CWD monitoring system utilizing recreational hunters. We report the success of data capture after 6 years of surveillance. We provide an overview of CWD occurrence among the 24 wild reindeer areas and quantify the likelihood of disease absence in areas without detection.3. Surveillance aimed to test hunted reindeer aged ≥1 year. With higher quotas and extended hunting seasons, proactive surveillance was implemented in atrisk areas. There were several challenges of population demarcation and the lack of surveys required for risk-based sampling. Several specific tools for hunters have been developed, including digital apps for rapid reporting and feedback.Laboratory capacity was expanded, and novel statistical tools were developed for the specifics of the sampled tissues.4. The surveillance (2016-2021) achieved a sample return rate of 61.5% from a maximum of 22,123 harvested reindeer aged ≥1 year. Among these, 64.1% included both relevant tissues (retropharyngeal lymph nodes and brain), yielding 9412 (42.5%) complete samples of harvested reindeer. Samples originating from harvest constituted ~84% of total wild reindeer samples.

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