Septic peritonitis due to colonic perforation associated with aberrant migration of a Gasterophilus intestinalis larva in a horse.

The research is about an adult quarter horse mare that developed septic peritonitis due to the abnormal migration and deep penetration into the colon of a bot fly larva, leading to a colon perforation. This is the first known report of such a case.

Objective of the Research

• The main objective of the study was to investigate an unusual case of septic peritonitis in an adult horse. The cause of this condition was identified as a perforation in the colon due to an aberrant migration of a Gasterophilus intestinalis (bot fly larva).

Process of the Research

• The horse was presented with symptoms of acute colic and fever which led to further examination.
• A physical examination was conducted, including abdominocentesis (a procedure to remove fluid from the abdomen), which revealed septic peritonitis.
• Due to the gravity of the situation, the horse was euthanatized and a necropsy was performed to ascertain the cause of the ailment.
• The necropsy and subsequent histopathological examination uncovered a focal partial perforation in the right ventral colon. This perforation contained a single bot fly larva.
• The larva, later determined to be the third-instar larva of Gasterophilus intestinalis, was buried deep within the muscular layers and the submucosal regions of the colon.

Conclusion from the Research

• It was concluded that although bot fly larvae are known to attach to unusual sites within the digestive system of the host, this was the first known case of a larva penetrating so deep into the colon, resulting in a perforation.
• The perforation in the colon subsequently led to leakage of the intestinal content, which progressed to septic peritonitis.
• This research sheds new light on the disease-causing potential of the bot fly, specifically the larva, and opens up a new area of study regarding its management and impact on horses.