Intestinal displacements in older harbour and grey seals

Area of Science:

• Veterinary Pathology
• Marine Mammal Health
• Gastrointestinal Diseases

Background:

• Intestinal displacements (volvulus, torsion, invagination) are documented in mammals.
• Seals, both terrestrial and marine, can experience these conditions.

Purpose of the Study:

• To investigate the prevalence and characteristics of intestinal displacements in seals.
• To identify potential risk factors and associated pathologies in affected seals.

Main Methods:

• Pathological examination of 157 stranded or captive seals (harbour and grey seals) between 1996 and 2015.
• Analysis of intestinal displacements, including volvulus and invagination, and associated pathological findings.
• Correlation of findings with seal species, age, sex, and season.

Main Results:

• Intestinal displacements occurred in 23% of free-living harbour seals, 5% of stranded grey seals, and 17% of captive harbour seals.
• Intestinal volvulus (twisting) was found in 24 cases, leading to infarction. Invagination occurred in 11 cases.
• Pregnant harbour seals showed a tendency towards increased risk of volvulus during April-June, suggesting periparturient vulnerability.

Conclusions:

• Intestinal displacements are a significant pathological finding in harbour and grey seals.
• Pregnant females may be more susceptible to intestinal volvulus around the birthing period.
• The etiology of these displacements is likely multifactorial, potentially involving enteritis, parasitic, and bacterial infections.