Possibilities and limitations of the prevention of strangles outbreaks on horse farms

Abstract

Strangles is a highly contagious equine disease caused by Streptococcus equi ssp. equi. Prophylactic hygiene meosures as well as the identification and treotment of dinicolly inconspicuous comer animals ore necessary to prevent outbreaks of strangles. In order to find out to what extent prophyloctic measures can be used to prevent on outbreok or to reduce spread of the disease respectively, (lie questionnaire study described in the following wos performed. Two different questionnaires were sent to 298 horse farms ond 50 veterinorions in Germany. In order to take part in the study, farms had to keep ot leosl three horses. The forms were asked to grade prevention and hygiene measures, as well os the possibility 10 provide information for form personnel ond horse owners before ond during o strangles outbreak occording to their prac-ticability from ∗1 ▪ not realizable" to "10 "very well realizable". Veterinarians were asked about tho epidemiology of the disease, treotment ond recommendotions for the prevention of strongles. Of the 298 horse forms that received the questionnaire, 40 replied ond 31 answered the questions. Reosons for not completing the questionnaire were no more or less thon 3 horses on the farm, no contoct points to strongles, no interest in portcipoting in the study, problems with opening the questionnaire, or being o horse sanctuary. Prophylactic treatments such os hand disinfection seem to be harder to realize as o prophylactic measure thon during an outbreok. Information events seem to be possible to organise. As o main reason veterinarians believed the fluctuation of the horse population on ihe forms. Holf of the participating veterinarians reported complication such as dysphagia and gutturol pouch empyemo during the discose. As diagnostic sample, most ve'erinorions chose o nosol swob which wos exomined by o combination of microbiological culture ond PCR. As important means for disease prevention, they mentioned the introduction of quarantine ond hygiene measures such os seporotion of horses newly introduced to the forms and regular hand disinfection, larger farms were more positivo obout the use of social media and the release of veterinory confidentiality. Obviously, effective disease control con only be achieved by identification and successful treatment of diseased horses and clinically inopparent corrier animals. In case of on outbreak, odequote quorontine measurements including the separation of diseased from contact/suspicious animals os well os the separation of clinically healthy animals without previous contoct to affected animals must be realised. A colour-coded system (red, amber, green) has been well described. Direct communication of the onset of on outbreak allows neighbour ond contoct forms to olso introduce quarantine measurements ond screen the horses for Str. equi ssp. equi. Infected and contact horses can then be immediately separated occording the red-omber-green system and prevent further spreoding of the disease. As sompling techniques, the nasal and nosophoryngcal swob, tho nasopharyngeal wosh ond o guttural pouch lovoge hove been described. Ail of these hove their pras and cons ond the best sample for the stage of the disease should be used. To identify inopparent carrier onimols, o gutturol pouch lovoge sample exomined by PCR is most sensitive. Beside microbiology ond PCR, ontibody assays hove been described. Overall, this questionnaire study clearly shows that the practicability of effective prophylactic measures against strangles is higher in the cose of on outbreok thon os o prophylaclicalfy.