Outbreak of equine herpesvirus myeloencephalopathy in France: a clinical and molecular investigation

Equid herpesvirus 1 (EHV-1)-associated myeloencephalopathy (EHM) is a disease affecting the central nervous system of horses. Despite the constantly increasing interest about this syndrome, epidemiological data are limited especially when related to the description of large outbreaks. The aim of this article is to describe clinical, virological and molecular data obtained throughout a severe outbreak of EHM, with emphasis on laboratory diagnostic methods. The epidemic disease concerned a riding school in France where 7/66 horses aged 12-22 years developed signs of neurological disease in July 2009. Diagnosis of EHM was supported by EHV-1 detection using both real-time PCR and virus culture, and SNP-PCR test for viral strain characterization. EHM morbidity was 10.6% (7/66), mortality was 7.5% (5/66) and case fatality rate was 71.4% (5/7). Clinical presentation of the disease was characterized by the fact that fever was systematically present within 2 days before the severe neurological signs were noted. EHV-1 was detected by PCR in each available blood and nasal swab samples. Neuropathogenic strain only (G(2254) ) was isolated during the current outbreak; C(t) values, used as an indicative level of the viral load, ranged 26.0-37.0 among the six sampled horses. The amount of virus in biological samples was not systematically related to the intensity of the clinical signs being observed. In conclusion, this article described a severe outbreak of EHM while limited in time and restricted to one premise. Molecular data strongly suggested taking into account any low viral load as being a potential risk factor for neurological manifestations.

Expression of P-glycoprotein in the intestinal epithelium of dogs with lymphoplasmacytic enteritis

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory disease of the stomach, the small intestine and/or the large intestine. Loss of integrity of the intestinal barrier may be an important factor in the pathogenesis of IBD. In dogs, lymphoplasmacytic enteritis (LPE) is one of the recognized forms of IBD. P-glycoprotein (P-gp) is a membrane-bound efflux pump constituting an important component of the intestinal barrier. Changes in P-gp expression at the level of the intestinal barrier may be important in the pathogenesis of canine LPE, as this may lead to variable protection against xenobiotics and bacterial products in the intestine. The aim of the present study was to evaluate the expression of epithelial P-gp in the intestine in dogs with LPE compared with disease-free animals. Formalin-fixed intestinal biopsy samples from 57 dogs with histopathological evidence of LPE were immunolabelled with anti-P-gp antibodies (C494 and C219). Endoscopic biopsy samples of the duodenum and colon from 16 healthy beagles were used as controls. None of the control dogs had P-gp expression in the apical membrane of duodenal enterocytes, but all had P-gp labelling at the colonic epithelial surface. Twenty out of 57 dogs with LPE had P-gp expression at the apical surface membrane of villus epithelial cells in the duodenum, jejunum and/or ileum. Six out of 16 colonic samples from dogs with LPE had decreased P-gp expression at the epithelial surface compared with controls. It is unclear whether these changes in P-gp expression in dogs with LPE are a cause or a consequence of the inflammation. The observed changes could affect bioavailability of therapeutic drugs used in LPE.