Strangles is an upper respiratory infection. An infected horse show signs of fever, nasal discharge and typically have abscesses develop on the lymph nodes in the head and neck (Chhabra et al., 2023). However, some horses present with no symptoms acting more as carriers for the infection. When infected, horses will become lethargic, dull and will withdraw away from other horses. They may become reluctant to work and become difficult to handle (Scott, 2026). Horses with strangles will extend their neck and head to relief pressure on their throat and are less likely to graze due to pain. They will also display a loss of appetite and a reluctance to swallow (Boyle et al., 2018).

The first step for diagnosing strangles is to recognise the signs, symptoms and behavioural changes the horse is showing. The incubation period for the bacteria is 3-14 days with the usual first symptom being a high fever and a dullness in personality (Boyle, 2020). Examination and monitoring are important to track the fever and for any other symptoms that will start to develop, such as nasal discharge. The examination will focus on the jaw and throat to find abscesses and any swelling that may cause discomfort. There are two different methods of testing for S.equi. EIDS have a helpful guide to show how vets chose the best test for diagnosis (EIDS, 2026).

One method of testing is through PCR or culture testing. This process is done either by swabbing the abscesses or the nasal discharge or by a nasopharyngeal wash (Gronbaek et al., 2006). PCR testing is more sensitive than regular culture testing, with culture testing missing some early infections (Tran et al., 2024).

Second method of testing is a guttural pouch lavage. This is done by using an endoscope to access the guttural pouches, flushing the pouches with a saline solution and then collecting a sample of the fluid to then test through PCR testing (Barbazanges et al., 2026).

The first method of bacterial collection is an easier method of collection with less stress on the horse, however there are drawbacks to this method. Using samples from the nasal cavity can be contaminated with environmental bacteria which can impact the test results. Using samples from a nasal wash would be preferrable in the first method as it has been shown to have a more accurate test result.

The second method is a more complicated procedure with light sedation required to ease discomfort for the horse. This method has the most accurate testing results due to the samples coming straight from the source and having visual conformation of the abscesses and any additional swelling present (Rendle et al., 2021). However, this procedure would need to be preformed by a trained professional so will be a higher cost and will have a higher stress rate for the horse with extra people involved and additional medication needed.

Blood testing is also used in some cases to measure the antibodies present to fight against the infection. These tests include ELISA testing and serology testing. This line of testing has its drawbacks as it cannot be used to diagnose a current infection but is important in testing for past infections and levels of antibodies for future infections (Carpentier et al., 2024).

-Vaccination

Vaccination is the best prevention and most sustainable way to manage strangles. Vaccinating the horses limits the bacteria’s spread. It also helps prevent reliance on antibiotics once infected as the body will have a faster immune response limiting complications (Rendle et al., 2024).

-Quarantine

Quarantine and screen new arrivals to the yard. This limits the number of new pathogens being introduced to the herd (Boyle et al., 2018).

-Hygiene and husbandry

Strangles is spread through direct contact between fomites and infected horse. Its important to clean and sanitize shared areas and shared water buckets. Its also suggested to take temperatures twice a day to help monitor conditions (Fridberg et al., 2023).

-Biosecurity

Biosecurity is extremely important to limit the spread of the bacteria. One method for this a traffic light system. Red is for horses who have tested positive for strangles. Amber is for individuals who have come in contact with infected horses through direct or indirect contact. Green is for those who have no contact with any infected horses, they should still be monitored encase of any symptoms (Dechra, 2024).