Work with your vet to get an accurate diagnosis of your sick horse.
Related: Learn how your vet can test for Strangles.
Why is testing important?
The clinical signs of many respiratory diseases can look very similar to Strangles. Advanced tests, called PCR panels, allow vets to tell the difference between many respiratory diseases and Strangles. However, you won’t be able to make these distinctions from home.
Knowing what disease you are dealing with will help you and your vet make a plan for appropriate isolation, biosecurity, vaccination, and treatment.
It’s also important to remember that different diseases will be easier to pick up at different stages of infection.
In short: even if your horse has Strangles, his snot won’t have any bacteria in it until the lymph nodes start rupturing. But, because it’s possible he could have something other than Strangles, you should still get him tested right away!
Respiratory viruses, including EHV 1 and EHV 4, are more likely to be present in nasal secretions early in the course of the disease. This means that prompt collection of samples is important.
However, due to the behavior of the Strep. equi organism, sometimes testing early will result in negative results for Strangles even though the horse is actually infected.
The bacteria does not colonize the surfaces of the respiratory tract. Instead, it invades the lymph nodes within 3 hours of infection. This makes it undetectable by washes or swabs until the lymph nodes actually rupture and drain, which can occur 4-21 days after infection.
This means that you need to be patient in establishing a diagnosis. Even if the first test is negative, it may be necessary to test again at a later date.