Experimental Trichinella infection in seals

Area of Science:

• Veterinary Parasitology
• Marine Mammal Health
• Foodborne Pathogens

Background:

• Pinnipeds, including seals, are potential hosts for parasites.
• Trichinella nativa is a cold-tolerant parasite found in arctic wildlife.
• Understanding seal susceptibility is crucial for marine ecosystem health and food safety.

Purpose of the Study:

• To determine the susceptibility of grey seals (Halichoerus grypus) to Trichinella nativa infection.
• To evaluate the cold tolerance of Trichinella nativa muscle larvae in seal meat.
• To assess the potential for transmission of Trichinella nativa within marine mammal populations.

Main Methods:

• Grey seals were experimentally inoculated with varying doses of Trichinella nativa larvae.
• Muscle larval burden and distribution were analyzed at 5 and 10 weeks post-inoculation.
• Infected seal muscle was stored at different temperatures to assess larval freeze tolerance.
• Larval viability and infectivity were tested in mice.

Main Results:

• Seals exhibited susceptibility to Trichinella nativa infection, with dose-dependent larval burdens.
• Larval densities increased significantly from 5 to 10 weeks post-inoculation.
• Larval freeze tolerance improved with longer post-infection periods in the host.
• Trichinella-specific antibody levels rose during the experimental period.

Conclusions:

• Grey seals are susceptible to Trichinella nativa, with prolonged larval persistence.
• The increased freeze tolerance of larvae in older infections suggests a potential for transmission via scavenging.
• This study highlights the risk of Trichinella infection in marine mammals and potential zoonotic implications.