PERITONITIS IN HORSES ASSOCIATED WITH ACTINOBACILLUS EQUULI

Abstract

Actinobacillus equuli was the cause of peritonitis in 5 horses. In 3 the onset was sudden with intestinal stasis and acute abdominal pain as predominant findings. Two others presented with chronic disease and weight loss. Characteristically the peritoneal fluid had a high nucleated cell count with non-degenerate neutrophils as the predominant cell type. Four horses were treated and recovered.

Actinobacillus Pleuritis and Peritonitis in a Quarter Horse Mare

“…The combination of peritonitis and pleuritis in this mare was unusual, although in a study of 15 horses with A equuli peritonitis, two had concurrent A equuli pleuritis [3]. The cause of A equuli peritonitis is unknown, but larval migration of intestinal parasites has been suggested [3][4][5][6].…”

“…Actinobacillus peritonitis (with or without pleuritis) has a favorable longterm prognosis, with dramatic improvement evident usually within 24 to 48 hours of antibiotic commencement [3,4,6]. This may explain the low numbers of bacteria cultured in this case from the pleural fluid, as TMS had been administered 12 hours before admission.…”

“…Actinobacillus peritonitis is associated with larval Strongylus vulgarisinduced verminous aneurysms [6]. Examination per rectum in this case failed to detect lesions consistent with parasitic arteritis, but rectal impression of cranial mesenteric artery size correlates poorly with observed necropsy lesions [32].…”

“…Although only suggestive for parasitism, peripheral blood eosinophilia was absent and the mare had a good deworming history. A rotating larvicidal anthelmintic plan for horses with A equuli peritonitis seems advisable [6].…”

“…It seems that A equuli peritonitis (with and without concurrent pleuritis) has a good prognosis for recovery with appropriate antimicrobial therapy [3,4,6]. This is in contrast to other reports of peritonitis in horses, where mortality ranges from 30% to 67% [13,29,33].…”