What is EHD/Blue Tongue?

Last fall I returned from a deer hunt in SW North Dakota where we were filming for Bucks of Tecomate. The location I was hunting had been hit the year before by Epizootic Hemorrhagic Disease (EHD) and unknown to me I was going to be in for a crash course in what this fatal disease is. Although many people refer to EHD as Blue Tongue, it’s important to realize these two diseases are anti-genetically different. Very similar clinical signs but truly classified differently.

Let’s start with how this EHD impacted our hunt. When we arrived we were informed that this area had been hit 100 miles by 100 miles with the disease. Although it had minimal impact on the does and fawns last year, it practically wiped out the mature bucks. Even as we walked the fields during this hunt, we often found remains from the previous year near water sources. When we film for Bucks of Tecomate we are pursuing mature bucks, which is hard enough on its own. I realized I was in for a massive challenge on this hunt, now knowing as much as 75 percent of their mature bucks had likely been stricken by EHD the year before.

Despite the results of this hunting trip, I thought it would be beneficial to explain what is EHD. This disease has picked up traction over the years and more states are being hit with it. EHD occurs when the deer have a lack of oxygen in the blood, causing hemorrhaging. It happens in almost an epidemic nature, so if you find a deer that has fallen victim to this, there will be more. It is a disease that tends to on-set in mid to late summer and it’s most common transmission and development is from biting flies or midge. Once this disease has attacked the herd, usually a hard freeze is required to stop the damage and eliminate the transmission through flies. It does have other avenues of transmission but the biting flies tend to cause the most damage.

So how do you know if this disease has hit your area? The most common signs are when you see deer losing their appetite and possibly fear for man. They will grow progressively weaker and salivate excessively. Deer will run a substantially high fever, which forces them to water, usually lying in the water to try and bring their temperature down. Deer susceptible to EHD will develop signs within 7 days of exposure and it becomes fatal in many cases within 36 hours from that point.

So what can you do if you witness the signs? Unfortunately, there is no effective treatment for EHD or Blue Tongue. Although a vaccine could be created, it becomes very impractical to try and administer. It is always important to get your Department of Natural Resources (DNR) involved if you identify the symptoms or find a deceased deer in or near water ways. This allows the DNR to track the disease and depending on the impact may allow them to account for this when they conduct their census, which affects deer tags. If the deer herd is hit significantly, it is very important the DNR is allowed to manage this in the years to come, and keep the overall herd healthy.

My hope with this article is to create awareness for this disease and share some knowledge on it without getting too scientific as I know that can get boring. Don’t forget to keep an eye out for this and keep your DNR aware if you see signs.

Posted by Terry Sedivec