Are you tired of losing mature bucks year after year to EHD? Well, you are not alone! EHD (Epizootic Hemorrhagic Disease) is rapidly becoming an epidemic amongst white-tailed deer with more hunters and property owners finding dead deer, and more specifically mature bucks, succumbing to the disease. With this issue on a rise, we must turn to aquatic biology and Mother Nature for ways we can defend and reduce the EHD possibility.
What is EHD?
Epizootic Hemorrhagic Disease, otherwise known by its abbreviation EHD, is a viral disease that primarily affects white-tailed deer but can also infect other wild ruminants, such as mule deer, elk, and pronghorn. EHD is spread by biting midges (no-see-ums), primarily from the genus Culicoides. These insects thrive in low-quality, warm, wet environments, so outbreaks are more common in late summer and early fall and more so during drought conditions. The Culicoides midge reproduces in the shallow regions of water sources, tree holes, and rotting vegetation. As the eggs hatch and larvae mature, they leave the water and morph into winged adults. Once an adult, the females feed on blood of nearby mammals to prepare for another round of egg production. Given that mature bucks have a steady flow of blood on top of their heads, they make for a perfect blood supply for the female midge.
Why do deer seem to be the number one food source? Other than the fact that velvet is the fastest growing bone structure in the world, the female Culicoides midges are also crepuscular. This means that the female midge that is biting your mature bucks is most active at dawn and dusk the same as that buck is. The virus enters the bloodstream and replicates in endothelial cells, which line the deer’s blood vessels. This leads to widespread vascular damage, internal bleeding (hemorrhage), and fluid leakage. This vascular damage leads to high fevers, excessive salivation, respiratory distress, and ultimately death.
History of EHD
EHD was first reported in 1955 in New Jersey, where 700 whitetails succumbed to the disease. The disease was once again reported in Alberta in 1962, where another 440 whitetails, 18 mule deer, and 13 pronghorn died. Fourteen years later in 1976 another large epidemic outbreak occurred where thousands of whitetails died from EHD in Nebraska, Wyoming, Kansas, New Jersey, and the Dakotas, and 4,000 antelope died in Wyoming. (Matschke, G.H., Trainer, D.O., et. al. “Population Influences” chapter, p. 174, in White-tailed Deer: Ecology and Management, Edited by Lowell K. Halls, Stackpole Books, 1984, ISBN 0-8117-0486-6). In 2007, the Southeastern Cooperative Wildlife Disease Study (SCWDS) reports indicated 65,000+ whitetails died of this disease in a total of 31 states. Only a short five (5) years later in 2012, the herd was once again impacted in a total of 30 states with a total of 14,032 wild deer reported dead from EHD in Michigan alone!
Though these noted outbreaks are dated, the most recent severe cases were in the years 2019 and 2024. So with all of these outbreaks, what was the leading cause of them?
Drought and Dead Water = Dead Deer
During times of drought or dry seasons, clean, flowing water sources dry up, and deer congregate at what remains for water sources which many times have poor water quality. Culicoides midges breed in these moist, muddy, organic-rich environments, especially around the edges of stagnant or polluted water sources. Therefore, when deer congregate around these water sources disease transmission becomes more likely.
Poor water quality is caused by things like animal waste runoff, decaying vegetation, fertilizer runoff, and/or algal blooms. As organic matter and nutrient loads increase, the beneficial biota within the water reduces which decreases internal food web competition and allows for the midge to reproduce more rapidly and increase disease possibility amongst deer herds.
As indicated in Thomas Lindsay Jr.’s article “Can We Prevent EHD?” (Thomas Lindsay Jr. “Can We Prevent EHD?” Web blog post. National Deer Association. N.p., 30 Mar. 2013. Web) this genus of insects has one flaw that overlaps with the expertise of an aquatic biologist. This overlap is that of water quality. Ed Schmidtmann, a researcher with the Arthropod-Borne Animal Diseases Research Unit, part of the USDA Agricultural Research Service, noted in his research and teachings that Culicoides is a creature that thrives in degraded water sources. Taking Ed’s teachings, Lindsay Jr.’s article, and my years of experience and research in the aquatic management industry, it is safe to say we must target poor water quality to give our deer herds a fighting chance.
Water sources are constantly going through a process called eutrophication which is when a body of water increases in nutrients, especially nitrogen and phosphorus. These nutrients often come from fertilizer runoff, sewage, or animal waste. The simplicity of this is that as water quality decreases so does competition within the food chain. This allows the Culicoides midge to thrive and create more of an issue in drought years. However, if we can improve water quality thus increasing internal food chain competition, we find that the midge is unable to thrive.
The goal of aquatic management is to slow down and even reverse the eutrophication process. This can be achieved by creating and maintaining balance within the aquatic ecosystem. This balance is created by ensuring the correct amount of beneficial biota is present throughout the water source. When creating this balance in a water body we must first start at the microscopic level. The food chain is broken if the first level of that chain is non-existent. What is this first layer? The presence of beneficial microbial bacteria.
At the sediment or “muck” interface of a pond we can observe many species of bacteria working on nitrification, ammonification, oxidation, and decomposition. If beneficial, aerobic bacteria do not exist at this interface we find that these natural processes that ensure water quality and health fail to exist as well. This paves the path for the midge to once again thrive and wreak havoc on deer populations.
Healthier Water, Healthier Deer
To achieve the high water quality needed to reduce EHD possibilities, we need to give Mother Nature a helping hand. This is achieved by adding beneficial bacteria and enzymes to the water and sediment (muck). EHD-fenseTM is a water treatment kit that does just that. The kit provides the helping hand we have been longing for. EHD-fenseTM is a three-step prevention system consisting of CatapultTM (biocatalyst enzymes), LiveWaterTM (dry probiotic beneficial bacteria formulation), and D-MuckTM (pelletized muck reducing probiotic beneficial bacteria). This simple and convenient three-step process focuses on the root cause of the poor water quality that the EHD midge prefers.
To begin the transformation of the water source we begin with CatapultTM, which is a blend of biocatalyst enzymes that focus on speeding up biological processes within the aquatic ecosystem. In this case, we are focused on muck and nutrient remediation processes. What do the enzymes within CatapultTM provide? The enzymes expedite the decomposition of organic materials and set the table for beneficial bacteria to go to work. The organic materials that reside in these systems may be dead organisms, leaves, feces, or even decaying algae. CatapultTM targets these organics and begins breaking them down into simple sugars. These simple sugars are what the beneficial bacteria in LiveWaterTM and D-MuckTM need to thrive, reproduce, and grow. The more of these simple sugars present in the ecosystem, the more efficient the beneficial bacteria will work.
Now that the table is set, we focus on the next steps of the EHD-fenseTM treatment kit. This is the addition of two unique and equally powerful probiotics, LiveWaterTM and D-MuckTM. What will the beneficial bacteria in LiveWaterTM and D-MuckTM be working on? Organics! The bacteria will begin to remediate the organics by converting these once unhealthy substances into a combination of oxygen (O2), carbon dioxide (CO2), water (H20), and non-usable forms of nutrients thus eliminating the potentially harmful organics from the ecosystem. With these organics being remediated out of the environment the main breeding and living space of the midge is removed.
In Summary
EHD has been on the forefront of whitetail health issues, but by using aquatic biology we can finally provide a solution to the problem. With the knowledge that the aquatic midge (Culicoides) responsible for EHD prefers degraded water sources with no competition from other aquatic life we finally have a way to take the fight to the midge. By applying beneficial bacteria and enzymes found in the EHD-fenseTM water treatment kit the midge’s breeding areas can be removed. You will now be able to reduce the population potential that the midge could achieve, thus decreasing the midge population threshold and increasing the survival of your whitetail deer. Year after year your water sources will show improved ecosystem health which makes way for more beneficial invertebrates (both macro and micro), aquatic insects, and amphibians that outcompete the EHD carrying midge. Your deer herd will be thanking you as they will be able to go to water sources without worrying about being bit by the EHD midge and give you more opportunities to put bucks on your wall rather than finding them dead before your deer season even starts. Let’s face it, we spend a lot of time and money managing properties for big whitetail bucks and we can look at the EHD-fenseTM water treatment system as an insurance policy on our deer. With the EHD-fense system in place the sky is the limit with increasing the water quality of your water sources and increasing the competition that the midge fly will have. As we would like to say, No Dead Water, No Dead Deer!
— By Zach Haas, Senior Aquatic Biologist & Owner CreekBottom Land Management
