Onchocerca lesions in moose (Alces alces L.)

Area of Science:

• Veterinary Pathology
• Parasitology
• Wildlife Health

Background:

• Onchocerca worms are known filarial nematodes that can infect various animal hosts.
• Previous studies have documented Onchocerca infections in cervids, but specific data on moose are limited.
• Understanding the prevalence and impact of parasites in wildlife populations is crucial for conservation and management.

Purpose of the Study:

• To investigate the prevalence and characteristics of Onchocerca-induced lesions in moose.
• To determine the potential impact of these lesions on moose health and meat hygiene.
• To identify the Onchocerca species or strain responsible for the observed lesions.

Main Methods:

• Necropsy and histopathological examination of moose tissues.
• Macroscopic identification of inflammatory granulomas.
• Microscopic analysis of granuloma composition and associated parasites.
• Morphological comparison of recovered worms with known Onchocerca species.

Main Results:

• Inflammatory granulomas were present in 98% of moose aged 1.5 years or older; no lesions were observed in calves.
• Lesions were predominantly located in tendinous tissues, particularly at the insertions of the M. sartorius and M. semitendinosus at the tibia.
• The inflammatory reaction was benign, with lesions deemed of minor importance for animal health, mobility, and meat hygiene.
• Recovered worms exhibited similarities to Onchocerca tarsicola, but a moose-specific species or strain could not be ruled out due to high prevalence and adaptation.

Conclusions:

• Onchocerca infections are highly prevalent in adult moose, manifesting as benign granulomas in tendinous tissues.
• These lesions have minimal negative impact on moose health, mobility, and meat safety.
• Further research is needed to definitively identify the Onchocerca species or strain affecting moose populations.