B- and T-cell lymphocytes and other immune cell infiltration in the duodenal and rectal mucosa of severe asthmatic horses.

OBJECTIVE: The objectives of this study were to quantify lymphocytes and eosinophils in the mucosa of the duodenum and rectum in asthmatic horses. ANIMALS: 8 healthy and 10 asthmatic horses. PROCEDURES: Asthmatic horses were evaluated in a symptomatic (after 6 weeks of exposure to moldy hay) and asymptomatic status (3 and 7 months after being fed alfalfa pellets [n = 4] or treated with inhaled fluticasone [6]). Duodenal and rectal biopsies were endoscopically (n = 4 to 6) taken in each horse. Eosinophils were counted on slides stained with hematoxylin, eosin, phloxine, and saffron, and immunohistochemistry was used to evaluate T and B lymphocytes using CD3 and CD20, respectively. RESULTS: The duodenal and rectal epithelium of asthmatic and control horses contained exclusively T lymphocytes (CD3). Symptomatic asthmatic horses, compared to controls, had a significantly higher number of T lymphocytes (CD3) in the duodenal epithelium (P = .016) and the adjacent lamina propria of the villi (P = .04). Compared to symptomatic asthmatic horses, the fluticasone-treated group had significantly fewer T lymphocytes in the total lamina propria of the rectal mucosa (P < .01). CLINICAL RELEVANCE: Taken together, these results suggest that asthmatic horses have greater infiltration of T lymphocytes in the duodenal and rectal mucosa, indicating a certain degree of inflammation, which could be due to a systemic inflammatory effect and/or a local effect of ingested hay allergens in asthmatic horses. Systemic markers of inflammation have not been investigated to better qualify if the infiltration noted is due to a local and/or systemic effect.

Molecular Surveillance of EHV-1 Strains Circulating in France during and after the Major 2009 Outbreak in Normandy Involving Respiratory Infection, Neurological Disorder, and Abortion.

Equine herpesvirus 1 (EHV-1) is an Alphaherpesvirus infecting not only horses but also other equid and non-equid mammals. It can cause respiratory distress, stillbirth and neonatal death, abortion, and neurological disease. The different forms of disease induced by EHV-1 infection can have dramatic consequences on the equine industry, and thus the virus represents a great challenge for the equine and scientific community. This report describes the progress of a major EHV-1 outbreak that took place in Normandy in 2009, during which the three forms of disease were observed. A collection of EHV-1 strains isolated in France and Belgium from 2012 to 2018 were subsequently genetically analysed in order to characterise EHV-1 strain circulation. The open reading frame 30 (ORF30) non-neuropathogenic associated mutation A2254 was the most represented among 148 samples analysed in this study. ORF30 was also sequenced for 14 strains and compared to previously published sequences. Finally, a more global phylogenetic approach was performed based on a recently described Multilocus Sequence Typing (MLST) method. French and Belgian strains were clustered with known strains isolated in United Kingdom and Ireland, with no correlation between the phylogeny and the time of collection or location. This new MLST approach could be a tool to help understand epidemics in stud farms.

Evaluation of athletic performance in horses with jugular vein thrombophlebitis: 91 cases (1988-2005).

OBJECTIVE: To evaluate effects of thrombophlebitis of 1 or both jugular veins on athletic performance of horses. DESIGN: Retrospective case series. ANIMALS: 91 horses with jugular vein thrombophlebitis. PROCEDURES: Medical records of horses with jugular vein thrombophlebitis examined between 1988 and 2005 were reviewed for signalment, history, clinical signs, diagnosis, and treatment. Performance was evaluated in 2 ways. A questionnaire was used to obtain a subjective assessment from the owner or trainer of the horse's performance after thrombophlebitis, compared with the performance before thrombophlebitis. Racing records from before and after thrombophlebitis were also evaluated. RESULTS: Thrombophlebitis was diagnosed in 37 horses at the time of admission (group 1), and 54 horses developed thrombophlebitis during hospitalization for an unrelated medical condition (group 2). Twenty-seven of 81 (33%) owners answered the questionnaire, and racing records were available for 31 horses. Performance data were available for 48 horses. Owners reported that all nonracing horses, except 1, had equivalent or better performances after discharge. Twenty-six of 31 (84%) Standardbreds resumed racing; in these horses, there was no significant difference between racing times before and after thrombophlebitis. No significant difference in performance was detected regardless of the primary disease, whether a horse had unilateral or bilateral thrombophlebitis, or the treatment administered. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the athletic performance of horses used for nonracing events was not affected by thrombophlebitis. Thrombophlebitis in racing Standardbreds was associated with a decreased chance of return to racing; however, performance was not impaired in those that resumed racing.