Reasons for performing study:To present the first report of a case series concerning equine idiopathic muscular hypertrophy of the oesophagus (IMHO). Objectives: To investigate the clinical and pathological features of the disorder. Methods: The medical records of 31 horses suffering from the disorder were reviewed retrospectively. In all these animals the diagnosis was confirmed at post mortem examination. Results: The median age of the affected horses was 12.5 ± 5.6 years (range 1-26) without sex or breed predilection. Only 2 out of 31 horses showed clinical signs associated with oesophageal dysfunction, indicating that the muscular hypertrophy was rather a coincidental post mortem finding. Histology revealed thickening of the distal portion of the oesophagus mainly involving the circular layer of the tunica muscularis without fibrosis or inflammation. In 8 cases, the disorder was seen in concurrence with idiopathic hypertrophy of the tunica muscularis of various other parts of the gastrointestinal tract. Conclusions: In the majority of patients, IMHO was a coincidental finding at post mortem examination usually confined to the smooth, circular muscle layer of the tunica muscularis externa. Potential relevance: Further research is necessary to study the precise effect of IMHO on oesophageal function.

Acinetobacter spp. are aerobic, rod-shaped Gram-negative bacteria belonging to the Moraxellaceae family of the class Gammaproteobacteria and are considered ubiquitous organisms. Among them, Acinetobacter baumannii is the most clinically significant species with an extraordinary ability to accumulate antimicrobial resistance and survive in the hospital environment. Recent reports indicate that A. baumannii has also evolved into a veterinary nosocomial pathogen. Although Acinetobacter spp. can be identified to species level by the use of the matrix-assisted laser ionization time-of-flight mass spectrometry (MALDI-TOF MS) coupled with an updated database, molecular techniques are still necessary for genotyping and determination of clonal lineages. It seems that the majority of infections due to A. baumannii in veterinary medicine are nosocomial. Such isolates have been associated with several type of infections such as canine pyoderma, feline necrotizing fasciitis, urinary tract infections, equine thrombophlebitis and lower respiratory tract infections, foal sepsis, pneumonia in mink and cutaneous lesions in hybrid falcon. Given the potential multidrug resistance of A. baumannii, treatment of diseased animals is often supportive and should be based preferably on in vitro antimicrobial susceptibility testing. It should be noted that animal isolates show a high genetic diversity and are in general distinct in their sequence types and resistance patterns from those found in humans. However, it cannot be excluded that animals may occasionally play a role as reservoir for A. baumannii. In line, it is of importance to implement infection control measures in veterinary hospitals to avoid nosocomial outbreaks with multidrug-resistant A. baumannii.

Summary This review discusses the literature on B. burgdorferi infections in view of the rising incidence of this infection in general and the increasing concerns of horse owners and equine practitioners. Lyme disease, the clinical expression of Borrelia infections in man is an important health problem. The geographic distribution of B. burgdorferi infections in equidae should resemble that of human cases because the vector tick involved, Ixodes ricinus, feeds on both species and, indeed, the infection has been established many times in horses. However, a definite diagnosis of the disease "Lyme borreliosis" in human beings as well as in horses and other animals is often difficult to accomplish. Although a broad spectrum of clinical signs has been attributed to B. burgdorferi infections in horses, indisputable cases of equine Lyme borreliosis are extremely rare so far, if they exist at all.