Yew (Taxus) intoxication in free-ranging cervids

Area of Science:

• Veterinary Toxicology
• Wildlife Pathology
• Plant Toxicity

Background:

• Wild ruminants, particularly deer species (cervids), have been anecdotally considered resistant to yew (Taxus) intoxication.
• This perception is challenged by emerging evidence and case reports of yew toxicosis in Norwegian wildlife.

Purpose of the Study:

• To investigate and document cases of yew toxicosis in Norwegian wild ruminants.
• To identify the presence of yew alkaloids in affected animals and explore potential interspecies differences in tolerance.

Main Methods:

• Case reporting and post-mortem examination of affected wild ruminants (moose, roe deer, reindeer).
• Gross pathology, histology, and qualitative high-performance liquid chromatography-ion trap mass spectrometry (HPLC-IM-MS) for alkaloid detection.
• Analysis of ruminal contents for yew plant remnants.

Main Results:

• Five moose, seven roe deer, and two reindeer were found dead near yew plants, exhibiting signs of yew toxicosis.
• Key findings included pulmonary congestion, edema, effusions, cardiac abnormalities, and splenic congestion.
• Yew alkaloids (taxines) were detected in tissue samples, with levels correlating to visible yew ingestion.

Conclusions:

• Yew (Taxus) intoxication is a significant threat to wild ruminants, including moose, roe deer, and reindeer.
• Detection of taxines in tissues confirms yew ingestion as the cause of death.
• Further research is needed to understand interspecies tolerance and adaptive mechanisms to taxines.