THE POTENTIAL LONG-TERM INFECTIVITY OF OXYSPIRURA PETROWI EGGS TO INSECT INTERMEDIATE HOSTS OVER DIFFERENT SEASONS

Area of Science:

• Veterinary Parasitology
• Avian Ecology
• Wildlife Disease Epidemiology

Background:

• Oxyspirura (O.) petrowi eyeworms infect numerous North American birds, including vulnerable species.
• The epidemiology and environmental survival of O. petrowi eggs are poorly understood.
• Understanding egg infectivity is crucial for managing O. petrowi impacts on avian populations.

Purpose of the Study:

• To assess the long-term infectivity of O. petrowi eggs under seasonal conditions.
• To identify environmental thresholds influencing larval survival and egg inactivation.
• To evaluate the persistence and transmission risk of O. petrowi eggs.

Main Methods:

• Larvated O. petrowi eggs were placed in soil-filled mesh bags in an outdoor plot.
• Bags were collected after 1, 3, and 6 months during winter and summer exposure periods.
• Recovered eggs were counted, and the proportion of larvated eggs was determined to calculate inactivation rates.

Main Results:

• Total egg recovery decreased over time in both seasons (winter: 69.7% inactivation; summer: 67.9% inactivation).
• A significant drop in larvated eggs during winter coincided with a cold snap, indicating cold sensitivity.
• Approximately one-third of eggs remained larvated after both seasonal exposures, demonstrating high resilience.

Conclusions:

• Oxyspirura petrowi eggs exhibit remarkable resilience to seasonal environmental conditions.
• Extreme temperatures, particularly cold snaps, can significantly reduce egg infectivity.
• Persistent transmission risk necessitates integrated management strategies to protect vulnerable avian populations.