PSOROPTES INFESTATION AND TREATMENT IN AN ISOLATED POPULATION OF BIGHORN SHEEP (OVIS CANADENSIS)

Area of Science:

• Wildlife Ecology
• Veterinary Parasitology
• Conservation Medicine

Background:

• Bighorn sheep (Ovis canadensis) populations face threats from mite infestations, particularly Psoroptes mites.
• Small, isolated populations are highly vulnerable to disease impacts, necessitating effective treatment strategies.

Purpose of the Study:

• To evaluate the efficacy of novel treatments against Psoroptes mite infestations in a California bighorn sheep population.
• To assess the impact of amitraz-impregnated collars and cyfluthrin-impregnated ear tags on mite infestation severity.

Main Methods:

• Capture and individual mite infestation scoring of bighorn sheep (Ovis canadensis).
• Application of amitraz collars and cyfluthrin ear tags for treatment.
• Recapture and re-evaluation of infestation severity in subsequent years to assess treatment effects.

Main Results:

• No significant difference in infestation severity was found between amitraz and cyfluthrin treatments in the year following application.
• A significant decrease in mite infestation severity scores was observed from the beginning to the end of annual treatments.
• A notable reduction in median mite severity scores was detected between 2000 and 2006, potentially linked to cumulative treatment effects.

Conclusions:

• Annual treatments with amitraz or cyfluthrin may offer cumulative therapeutic benefits for Psoroptes mite infestations in bighorn sheep.
• Longer-acting avermectin drugs could be a more effective alternative for managing mite infestations in compromised bighorn sheep populations.
• Further research is needed to confirm the long-term efficacy of treatments and explore alternative drug formulations.