This is highlighted in the report "Wildlife Health Monitoring Program (ViltHOP) 2024", which has now been published. The purpose of the health monitoring program is to systematically collect and update data on the health status of Norwegian wildlife populations, with a primary focus on cervids, muskox, hare, and Arctic fox. In addition to monitoring diseases affecting wildlife, the program emphasizes infectious diseases that can be transmitted between wildlife and livestock, as well as from wildlife to humans (zoonoses).
Moose Calf Health in Focus in 2024
–The collection of samples and/or carcasses from 64 calves has provided us with valuable information on why moose calves die. This is an important supplement in understanding why moose populations are declining in some regions, says veterinarian and researcher Bjørnar Ytrehus at the Norwegian Veterinary Institute.
–Our investigations showed that the calves were small compared to expected size, emaciated, and weak. The preliminary conclusion is that the calves suffered from malnutrition, he explains.
At the same time, findings showed that the calves died of or with various infections. One of the conclusions in the report is that the causes of death are complex and multifaceted. Researchers are working with several key hypotheses in their continued investigations to further explain the widespread moose calf mortality.
Diarrhea in Roe Deer
Roe deer diarrhea is a chronic disease that is well-known in several areas of the country.
–As of today, we do not know the cause of this condition, says veterinarian and researcher Malin Reiten at the Norwegian Veterinary Institute.
–The disease is widespread in several European countries, including our neighboring countries Sweden and Denmark. However, research institutions in these countries have also not been able to identify the cause of the diarrhea. We have speculated whether roe deer diarrhea might be due to an imbalance in the gut microbiota, she explains.
One theory is that the roe deer consume food that is not well suited to their digestion. In recent years, there has been an increasing understanding of how crucial the gut microbiota (single-celled organisms, bacteria, and fungi) are for digestion and overall health.
–Small changes in diet can alter the gut flora. As a result, the animals may develop diarrhea. It is also possible that as-yet-undiscovered pathogens initiate or contribute to worsening the condition, Reiten continues.
To address the knowledge gap about roe deer diarrhea, sample collection from roe deer is currently ongoing. The project was still in the collection phase at the end of 2024.
Seeking More Information on Moose Diarrhea
Throughout 2024, several moose with diarrhea have been submitted to the Norwegian Veterinary Institute. The moose were autopsied and sampled, but it has not been possible to determine the cause of the diarrhea. All the cases came from the eastern part of the country. Researchers are highly interested in obtaining more information about moose diarrhea, particularly whether it occurs in other parts of Norway as well.
–We do not know whether moose diarrhea has any commonalities with chronic diarrhea in roe deer. It may also be caused by pathogens that we have yet to detect. This is why it is particularly important to obtain samples from animals in the early stages of illness, as chronic cases are less likely to reveal potential pathogens, says Malin.
The ViltHOP 2024 report also discusses relevant diseases in red deer, wild reindeer, hare, and muskox.
About ViltHOP
ViltHOP is a nationwide program aimed at collecting health data to support the sustainable management of wildlife populations.
The program places particular emphasis on diseases affecting cervids, hare, and muskox, as well as infectious diseases that can be transmitted between wildlife and livestock and from wildlife to humans (zoonoses). Additionally, the program focuses on how environmental and climate changes impact the health of wild ruminants. ViltHOP is also responsible for maintaining biological materials related to wildlife health monitoring in the ViltHOP biobank.
