Strangles is a disease of the lymph nodes of the upper respiratory tract in horses. It is endemic within the horse population of the UK. Affected horses typically have a high temperature, cough, poor appetite, nasal discharge and swollen or abscessed lymph nodes of the head which can appear as open sores. The disease may become fatal if the bacteria spread to other parts of the body or the respiratory tract is blocked by swollen lymph nodes (hence the term ‘Strangles’). However, in some horses, a nasal discharge without swelling of the glands is all that can be seen.
Direct contact between infected horses is the most obvious means of transmitting the infection but the hands and equipment of staff, vets or farriers can spread it indirectly. The bacteria are discharged from draining abscesses and the nose, and may survive the environment, particularly in water troughs. The incubation period is usually around 1 week but can be longer. A small proportion of horses that have recovered become persistently infected for months or even years. They are less susceptible to reinfection but can intermittently spread the disease to other horses.
Veterinary advice should be sought to determine whether the vaccine is available and whether its use may be appropriate on the basis of specific risk assessment.
When away from home, maintain good hygiene, avoid sharing equipment and drinking troughs and avoid direct contact between horses. Ideally, all horses entering any premises should be quarantined for a period of at least 2 weeks and monitored closely, particularly in the period immediately after arrival. Any horse that develops a nasal discharge or other signs of Strangles should be isolated and tested.. The Strangles blood test can be used to identify horses that been exposed to this disease in the recent past.
Call your vet immediately to reduce risk of further spread. Strangles is diagnosed either directly by detection of the bacteria, or indirectly by detection of rising levels of antibodies against the bacteria in blood samples.
All infected horses should remain in strict isolation, under the direction of a vet and with the highest possible standards of hygiene. Regular disinfection of water troughs should be performed in order to minimise the risk of spread. Horses should not enter affected premises unless they can be kept in strict isolation from all possible sources of infection. No infected or in-contact animal should be released from isolation or veterinary supervision until they have been tested negative for the disease.