Suppurative splenitis and peritonitis in a horse after gastric ulceration caused by larvae of Gasterophilus intestinalis.

The study details the case of a horse that developed severe inflammation of the spleen and abdominal lining following gastric ulcers caused by Gasterophilus intestinalis larvae, demonstrating a rare instance where these stomach-dwelling larvae led to significant systemic illness.

Case Presentation and Diagnosis

• The horse, a 12-year-old Thoroughbred mare, showed signs of being seriously ill, including lack of appetite, substantial weight loss, fluctuating fever, intermittent diarrhoea, depression, extreme thinness, and loss of coordination. All these symptoms began to appear after the horse suffered from colic, a common digestive disorder in horses.
• The horse was found to have an enlarged spleen by rectal palpation – a physical examination in which a vet uses their hands to feel for abnormalities in an animal’s internal organs.
• Laboratory tests on blood samples revealed significant changes, including severe leucocytosis (a high white cell count, which typically indicates an immune response to infection), and hyperproteinaemia characterised by hypoalbuminaemia and hypergammaglobulinaemia (indicating changes in protein levels, again suggesting infection or inflammation).

Post Mortem Examination

• Following the horse’s death, an autopsy revealed several key abnormalities. These included low-grade pleurisy (inflammation of the tissues that line the lungs and chest cavity) and peritonitis (inflammation of the membrane lining the abdominal wall and covering the abdominal organs) with fluid accumulation in both these cavities.
• Most critically, the examination found severe gastritis (inflammation of the lining of the stomach) with full-thickness perforations (holes) in the stomach wall. These were associated with larvae of Gasterophilus intestinalis. These larvae had moved to the adjacent spleen from the stomach, causing a massive inflammatory, or suppurative, response in the spleen (suppurative splenitis).
• In addition, Streptococcus zooepidemicus, a bacterium often associated with infections in horses, was cultured.

Significance of Findings

• These findings indicate a rare, but severe, systemic disease progression – from gastric ulceration caused by Gasterophilus intestinalis larvae towards severe inflammation of the spleen and the lining of the abdomen. It demonstrates the potential of stomach-dwelling larvae, commonly found in horses, to lead to serious infections if they breach the stomach wall.
• Furthermore, it underscores the importance of early detection and treatment of gastric ulcers and infestations in horses, to prevent potential catastrophic complications.