A retrospective study of equine actinobacillosis cases

Abstract

Abstract. Several Actinobacillus spp. are common commensal bacteria of the oral cavity, gastrointestinal tract, and reproductive tract of horses and can cause disease in both foals and adults. The current retrospective study was designed to review Actinobacillus spp. isolated from clinical samples or necropsies of 99 horses during 1999-2011. The cases consisted of 43 foals (<6 months of age), 4 young adults (6 months-2 years), 39 adults (>2 years of age), 2 aborted fetuses, and 11 with unspecified ages. Clinical history, signs, bacterial species isolated, and associated lesions were documented. Actinobacillus spp. were isolated 111 times. The most common isolates were Actinobacillus equuli subsp. equuli (38.7%) and hemolytic Actinobacillus spp. (24.3%). Other isolates were Actinobacillus lignieresii (5.4%), Actinobacillus pleuropneumoniae (1.8%), and unclassified Actinobacillus spp. (28.8%). Actinobacillus equuli subsp. equuli was most commonly isolated from clinical and necropsy cases of septicemia and respiratory disease in both foals and adults. Embolic nephritis, the classical septicemic lesion of equine neonatal actinobacillosis, was also present in several adult septicemic actinobacillosis cases. Predisposing factors such as failure of passive transfer of colostral antibodies as well as concurrent pathogenic bacterial or viral infections were present in numerous actinobacillosis cases. There were many cases, however, for which a predisposing factor or concurrent infection was not documented or apparent, suggesting that Actinobacillus spp. can be primary pathogens under the right circumstances and in the right location.

Characterization and comparison of the bacterial microbiota in different gastrointestinal tract compartments of Mongolian horses

“…The Proteobacteria Actinobacillus of the family Pasteurellaceae was also abundant in the UG and forms part of the normal microbiota of the anterior intestine of ruminants. However, Actinobacillus is a conditional pathogen that can cause diarrhea, meningitis, pneumonia, pyogenic nephritis or septic polyarthritis (snoring or joint disease), and sepsis, indicating that its balance is critical to the health of the animal (Layman, Rezabek, Ramachandran, Love, & Confer, 2014). In the hind or lower gut, Firmicutes and Bacteroidetes were predominant, which demonstrated that the LG is the main region for fermentation of plant fiber.…”

Diseases of the Equine Urinary System

“…1 Actinobacillus equuli subspecies equuli is most commonly encountered with equine septicemia, embolic pneumonia, and nephritis due to Actinobacillosis. 44 Sporozoan Klossiella equi is typically nonpathogenic in horses, but with high parasitic load, tubular degeneration and interstitial nephritis have been reported. 1,45 The life cycle involves glomerular endothelial cells, proximal convoluted tubules, and the loop of Henle before release of sporocysts into the urine.…”

“…42 Septicemia from Actinobacillus species in adult horses and foals will disseminate and shower the kidney, resulting in embolic nephritis. 1,44 Emboli histologically consist of multiple cortical abscesses that grossly appear as pinpoint, slightly raised, tan-gray foci. 1 Actinobacillus equuli subspecies equuli is most commonly encountered with equine septicemia, embolic pneumonia, and nephritis due to Actinobacillosis.…”

Nachweis von Actinobacillus equuli ssp. equuli bei Saugferkeln mit eitriger Polyarthritis und Tendovaginitis

“…Eine Erkrankung kann sowohl bei Fohlen als auch bei adulten Tieren auftreten. Als prädisponierende Faktoren werden neben einer ungenügenden Übertragung kolostraler Antikörper gleichzeitig auftretende Infektionskrankheiten genannt, die die Immunität der Tiere schwächen [9]. Untersuchungen zu spezifischen Antikörpern gegen A. equuli beim Schwein sind den Autoren nicht bekannt.…”

“…Beim Fohlen wird eine antibiotische Therapie in Kombination mit unterstützenden Maßnahmen (z. B. Antiphlogistikagabe) empfohlen [9] [21]. Dennoch sind trotz individueller Behandlungsmöglichkeiten die Therapieaussichten ungünstig.…”