An Outbreak of Strangles in Arabian Horses in Saudi Arabia: Epidemiology, Clinical Signs and Treatment Outcomes

Abstract

This study was carried out to investigate an outbreak of strangles in horses at the Qassim Region, Central Saudi Arabia. From 29 horses included in this study, the disease was observed in 13, five of them were died: representing a morbidity rate of 44.8% and a mortality rate of 17.24%. The morbidity and mortality rates significantly (P≤0.05) differed among different age groups. In contrast, the case fatality rate was not significantly different among different ages. Gender has no significant effect on disease occurrence. Clinically, signs observed in infected horses were high fever, anorexia, soft non-productive cough, muco-purulent bilateral nasal discharge, enlargement and abscessation of submandibular lymph nodes. Metastatic infection, including abdominal abscessation, was observed in 5 of the infected cases where signs of acute abdominal pain were recorded. Streptococcus equi subspecies equi was the only organism isolated from the lesions. Significant increases in the total white blood cells and neutrophils were detected in the diseased horses compared to healthy ones. Penicillin therapy, surgical intervention of the ripened sub-mandibular abscesses, isolation of healthy horses away from infected ones and thorough disinfection of the contaminated environment were the control measures that were applied to manage this outbreak. Treatment was very effective in the typical form of the disease whereas it had no value in the bastard form. Finally, it can be concluded that strangles in horses in the Qassim Region represents a great risk due to the high case fatality rate, and therefore using a protective vaccine is essential.