Last program I talked about preventing contagious equine diseases from spreading at boarding stables and horse farms by quarantining all new horses for 3 weeks.  Of course it is also important to make sure all horses have a current Coggins test before being allowed to enter the premises.  Another concern is strangles.  Strangles is a serious upper respiratory tract disease that is caused by the bacteria strep equi and is highly contagious.  The difficulty with strangles is that some horses can be chronic carriers and shed the organism while not showing any clinical signs; a horse could enter a stable and appear completely normal and yet be contagious.  Because of this, it is recommended to test all new arrivals for strangles.  Strangles testing is sort of involved as it requires flushing fluid up into the nasal cavity and collecting it for culture and another test called a PCR.  If a horse is determined to be a shedder, it must be isolated until they are no longer shedding.  Carrier horses can maintain the organism in two pouches in the back of their throats called guttural pouches.  Treating these pouches with penicillin can kill the organism and prevent the horse from being contagious.  Although this is a lot of trouble, it should be considered when a new horse is entering an established herd to prevent strangles infection. 

Influenza is another contagious disease but is a virus and because the incubation period is very short, the 3-week quarantine period for new horses recommended on our last program will catch any influenza-infected horses to prevent exposure to the entire herd.  Join us on our next program when we will continue to discuss methods of preventing contagious equine diseases.