Modelling the Effect of Genotype (PRNP) Linked to Susceptibility, Infection Duration and Prion Shedding on Chronic Wasting Disease Dynamics of Cervids

In 2016, classical contagious Chronic Wasting Disease (CWD) was detected for the first time in Europe in wild reindeer (Rangifer tarandus) in Norway. One reindeer population of around 2,000 animals was culled, but the disease later reappeared in another, larger and less confined population, where two cases have been detected so far.

Host factors such as genetic susceptibility can strongly influence how epidemics develop. In this study, Mysterud and Osnes with a team involving UIO, NMBU, and our partners SVA and NVI, explored epidemic trajectories using a digital twin of the Norwegian reindeer population where CWD is assumed to persist. They tested different assumptions about how host genetics affect disease dynamics—looking at differences in susceptibility, disease duration, and the level of prion shedding during infection.

The findings show that genetic effects can lead to qualitatively different epidemic outcomes. For example, when susceptibility is genetically modulated, the epidemic shows a sharp peak followed by a decline. But when genetics also increase disease duration, the peak occurs at a similar time, yet prevalence stabilizes instead of declining. Sensitivity analyses suggest that the results depend strongly on parameter assumptions, highlighting the need for empirical studies to better predict the trajectory of CWD.

You can read the full article here.

Mysterud, A., Osnes, M. N., Dean, K. R. et al. Modelling the effect of genotype (PRNP) linked to susceptibility, infection duration and prion shedding on chronic wasting disease dynamics of cervids. Ecological Modelling 509, Article 111253 (2025). https://doi.org/10.1016/j.ecolmodel.2025.111253 

October 2025

Poultry farm density and proximity drive highly pathogenic avian influenza spread

Highly pathogenic avian influenza (HPAI) H5N8 viruses (clade 2.3.4.4b) have caused significant socioeconomic and ecological impacts worldwide, with France among the most affected countries. Effectively controlling future outbreaks requires a thorough understanding of how the virus spreads between farms, and the identification of the main risk factors.

In this study, Guinat et al., from our partners INRAE, ENVT, and ANSES, analysed the spread of HPAI H5N8 in south-western France during 2020–2021. They applied phylogeographic and phylodynamic tools to investigate virus transmission, and to pinpoint the main drivers of spread.

The findings indicated that a single introduction led to regional spread, mainly in duck farms. Duck farm density and poultry farm proximity were the main factors driving spread. Required density and proximity thresholds were identified to maintain effective control.

You can read the full article here.

Guinat, C., Valenzuela Agüí, C., Briand, FX. et al. Poultry farm density and proximity drive highly pathogenic avian influenza spread. Commun Biol 8, 1306 (2025). https://doi.org/10.1038/s42003-025-08687-4 

August 2025

Dominant HPAIV H5N1 Genotypes of Germany 2021/2022 are Linked to High Virulence in Pekin Ducklings

Highly pathogenic avian influenza viruses (HPAIV) of H5 clade 2.3.4.4b pose an ongoing threat worldwide.

Assessing virulence in Pekin ducklings in an intramuscular infection model revealed that the two genotypes that dominated the epidemiological situation in Germany during the period 2021 and 2022 were of high virulence. In contrast, rare genotypes were of intermediate virulence.

The genetic constellation of these reassortants pointed to an important role of the viral polymerase complex (RdRP), particularly the PB1 genome segment, in shaping virulence in ducklings.

In this article, scientists from the Friedrich-Loeffler-Institute conclude that viruses with high duckling virulence were the most successful in terms of geographical spread and duration of circulation, while genotypes with lower virulence remained in the minority during outbreaks and were detected in very limited geographical areas only. 

You can read the full article here.

Piesche, R., Breithaupt, A., Pohlmann, A. et al. Dominant HPAIV H5N1 genotypes of Germany 2021/2022 are linked to high virulence in Pekin ducklings. npj Viruses 2, 53 (2024). https://doi.org/10.1038/s44298-024-00062-0 

November 2024

A Spatially-heterogeneous Impact of Fencing on the African Swine Fever Wavefront in the Korean Wild Boar Population

In October 2019, South Korea’s first case of African swine fever (ASF) was reported in wild boar in the north of the country, leading to the implementation of a 2300 km-long fencing strategy, which, however, failed to stop the ASF wavefront from moving southward.

To understand this outcome, our partners from INRAE, ENVT and ANSES investigated the wavefront dynamics in different regions of South Korea and assessed the effectiveness of the fencing measures on ASF dispersal and wavefront velocity.

Their results suggest that the location of fencing and the ASF wavefront dynamics intertwined with the effectiveness of fencing, emphasizing the need to better understand the latent spread of disease diffusion.

You can read the full article here.

Lim, JS., Vergne, T., Kim, E. et al. A spatially-heterogeneous impact of fencing on the African swine fever wavefront in the Korean wild boar population. Vet Res 55, 163 (2024). https://doi.org/10.1186/s13567-024-01422-7

December 2024

Development of an Experimental Model Using Cold Stress to Assess the Pathogenicity of Two Moroccan AI H9N2 Isolates from 2016 and 2022 in Commercial Broiler Chickens

Since 2016, low pathogenic avian influenza virus (LPAIV) H9N2 became a major issue for poultry production in Morocco, especially during co-infections.

This study tested an experimental infection model using cold stress and without other pathogens. Broilers were infected with H9N2 strains isolated in 2016 and 2022. Results showed that the 2022 strain had higher virulence and viral shedding than the 2016 strain. Cold stress worsened clinical symptoms, allowing researchers to create a scoring system and validate the model.

With this new model, our partners from The IAV Hassan II , INRAE and ENVT are helping to improve our understanding of the pathogenesis of H9N2 and to support future research.

You can read the full article here.

Arbani O, Ducatez MF, Kadja-Wonou M, Salamat F, Kichou F, et al. (2025) Development of an experimental model using cold stress to assess the pathogenicity of two Moroccan AI H9N2 isolates from 2016 and 2022 in commercial broiler chickens. PLOS ONE 20(4): e0320666. https://doi.org/10.1371/journal.pone.0320666 

April 2025

First Outbreak of African Swine Fever in Sweden: Local Epidemiology, Surveillance, and Eradication Strategies

In September 2023, African swine fever (ASF) was confirmed in wild boar in Sweden, making the country part of the current global ASF epidemic that started in Georgia in 2007. This article describes the local epidemiology, including the spatiotemporal dynamics of the outbreak and some of the factors that may have contributed to its apparently successful eradication. Through their research, our partners from the Swedish Veterinary Agency (SVA) provided key datas for our Integrative and Interdisciplinary Approach .

You can read the full article here.

Chenais E, Ahlberg V, Andersson K, Banihashem F, Björk L, Cedersmyg M, Ernholm L, Frössling J, Gustafsson W, Hellqvist Björnerot L, Hultén C, Kim H, Leijon M, Lindström A, Liu L, Nilsson A, Nöremark M, Olofsson KM, Pettersson E, Rosendal T, Sjölund M, Thurfjell H, Widgren S, Wikström-Lassa E, Zohari S, Ågren E, Ågren E, Ståhl K, First Outbreak of African Swine Fever in Sweden: Local Epidemiology, Surveillance, and Eradication Strategies, Transboundary and Emerging Diseases, 2024, 6071781, 15 pages, 2024. https://doi.org/10.1155/2024/6071781

June 2024

Zoonotic Potential of Chronic Wasting Disease after Adaptation in Intermediate Species

Chronic wasting disease (CWD) is a highly contagious prion disease affecting members of the Cervidae family (e.g. reindeer, red deer, and moose). In this research letter, the team discusses the potential capacity of CWD to transmit to sheep or other farmed animals, which could have significant implications for animal and public health.

You can read the full article here.

Barrio T, Benestad SL, Douet J, Huor A, Lugan S, Aron N, et al. Zoonotic Potential of Chronic Wasting Disease after Adaptation in Intermediate Species. Emerg Infect Dis. 2024;30(12):2691-2694. https://doi.org/10.3201/eid3012.240536

December 2024