Extracting Protostrongylus spp. larvae from bighorn sheep feces

Area of Science:

• Veterinary Parasitology
• Wildlife Health
• Mammalian Ecology

Background:

• Accurate detection of parasitic larvae in wildlife feces is crucial for population health monitoring.
• Previous methods for Protostrongylus spp. (lungworm) larval detection in bighorn sheep (Ovis canadensis canadiensis) were inefficient.
• Larval distribution within fecal pellets impacts extraction success.

Purpose of the Study:

• To evaluate methods for improving the detection and quantification of first-stage Protostrongylus spp. larvae in bighorn sheep fecal samples.
• To compare larval distribution in bighorn sheep pellets versus white-tailed deer (Odocoileus virginianus) pellets.

Main Methods:

• Comparison of larval extraction from whole versus crushed semi-dried fecal pellets.
• Evaluation of a modified beaker extraction method using tissue and screen filters.
• Assessment of larval distribution within fecal pellets for two different host-parasite systems.

Main Results:

• First-stage Protostrongylus spp. larvae were concentrated in the core of bighorn sheep pellets, with only 22% extractable from whole pellets.
• Crushing semi-dried pellets increased larval yield sevenfold and correlated with total larval counts.
• First-stage Parelaphostrongylus tenuis larvae from white-tailed deer were predominantly near the pellet surface.

Conclusions:

• Crushing semi-dried fecal pellets is essential for accurate Protostrongylus spp. larval quantification in bighorn sheep.
• The modified beaker extraction method with tissue provides cleaner samples without compromising larval recovery.
• Larval location within fecal pellets differs significantly between bighorn sheep and white-tailed deer, influencing detection methods.