Alabama Deer Association Events

What is EHD and BTV?

Epizootic hemorrhagic disease (EHD) and bluetongue virus (BTV) are viral diseases, collectively called hemorrhagic diseases (HD), and are common in white-tailed deer. Both diseases are transmitted by biting midges often called “no-see-ums” or gnats. Neither disease is a human health issue, but they can cause significant mortality in white-tailed deer. Outbreaks of HD tend to impact deer populations locally, meaning an outbreak may occur in one part of a county but not in other parts.

When do EHD outbreaks occur?

EHD and BTV outbreaks often occur in late summer and early fall (August-September), especially in years with drought-like conditions. Drought causes water sources to shrink, which creates warm, shallow, and stagnant pockets of water creating ideal breeding habitat for the midges that transmit EHD. Deer also congregate in these areas to find water, which helps the midges pass the disease between infected and healthy deer. EHD outbreaks can last until a frost that kills the midges. Key to the midge’s existence is the presence of a mud substrate. One biologist said a stock pond was the ideal setting for midge reproduction. Living in the shallowest water where oxygen is scarce, midge larva has few predators.

What are the signs of a deer with EHD?

Deer with EHD often appear weak, lethargic, and disoriented. Other signs of EHD in deer are ulcers in the mouth or on the tongue, swollen face, neck, or eyelids, and a bluish color to the tongue. Deer with EHD often search for water to combat the fever caused by the disease. EHD can be confirmed by testing blood and tissue (i.e., spleen) samples, but samples must be collected shortly after death.

Need Help with Your Battle Against No-See-Ums?

CO2 Traps — Much like mosquitoes, no-see-ums are attracted to the CO2 emitted from these traps. DynaTrap has a wide selection of traps for indoor and outdoor use. CO2 attracts the insects close enough for them to be sucked into the trap by its quiet vacuum fan. Once trapped, the insects die from dehydration and will remain in the cage even when the trap is turned off.

Need Help with Your Herd Loss?

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