EHD in deer is a potential hazard in late summer and more so during a drought. Take steps to reduce the disease on your property.
The National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center released its 2017 Summer Outlook. Good news is virtually all of the lower 48 will see little to no drought through September. That’s a much-needed sigh of relief for farmers, wilderness firefighters and whitetail hunters.
The last few years have been hard on the southeast, Midwest and Pacific states, due to a drought that seemed as if it would never end. Wildfires ravaged large swaths of Appalachia and the high country of the Cascade Mountains. If NOAA’s prediction holds true, we’ll likely see much less destruction to our forests this year – and hopefully reduce the number of epizootic hemorrhagic disease (EHD) cases among our whitetail herds.
What is EHD
EHD is a strain of virus that closely resembles bluetongue, and can infect ruminants like cattle and deer. It’s spread by gnats, also known as a midge or no-see-um. The main vector of the hemorrhagic disease virus is Culicoides sonorensis. These gnats live around shallow ponds that cattle and deer frequent that are eutrophic, which means the quality of the water is low. The bugs lay eggs in the mud not far from the water and the larvae thrive, especially when the surrounding area is routinely disturbed, which disrupts vegetation growth. Feces from deer and cattle in an already muddy, shallow pond, increases eutrophication and midge reproduction.
When the larvae hatch, they feast at dawn and dusk, when whitetails are most active. The first week after a deer is infected, it will start to show signs of illness such as fever, swelling in the head, tongue, neck and eyelids; loss of appetite and difficulty breathing. Some have even observed whitetails seemingly lose their fear of humans. As the virus takes hold, ulcers show up on the tongue, fluid builds in their lungs and a high fever takes hold. Within 10 days or so, many infected deer will die. Not every whitetail will die from an infection, which is good news. After surviving a milder case of EHD, the deer will produce antibodies that could help it further down the line.
During hot summers, especially when there’s a drought, water holes start to disappear, further concentrating the midge larvae. The warmer and saltier the watering hole, the better the conditions for them to thrive. Then, due to the hotter weather, deer will drink more throughout the day, thus increasing their odds of coming into contact with EHD.
To make matters worse, longer periods of warm weather extends the breeding season for midges. Extended periods of hot weather can also increase the rate of virus growth in the insects. Females can lay eggs multiple times throughout the summer. As the eggs hatch, they’ll continue the cycle until the start of colder weather.
How to Curb the Spread of EHD
If hunters have any hope of preventing EHD, they need to supply water sources that are clean and unfavorable to midge reproduction. Our Wild Water systems offer a fresh, clean source of water because it’s covered until it flows from the tank. While some mud near any water source is inevitable, there will be much less while using a trough compared to a stagnant pond. That means less midges and spread of disease. Our Wild Water Supplement, which can be added to our troughs or any container, provides minerals and works as an attractant.
For natural watering holes, you can take steps to make them less attractive to midge reproduction. If you’ve got a shallow, warm and muddy pond that deer use regularly, consider placing rocks along the edge of it or planting vegetation along the perimeter. Midge reproduction tends to be less in clear, deep bodies of water with rocky or steep banks.
It’s impossible to manage every water source on your property. Smaller streams may dry up, creating shallow pools that are ideal for the insects to thrive. But any small effort by you can help to reduce infection rates. While it appears we’ll be free from a long-lasting, harsh drought this summer, we still need to be diligent about reducing the risk of EHD spreading to whitetails on our property.