New Hampshire Fish and Game (NHFG) has reported its first case of epizootic hemorrhagic disease (EHD) in state history. It was detected in a whitetail deer that was found dead in Merrimack County. The disease, which is caused by biting midges, had been found in nearby states such as Vermont, New York, and Connecticut, but never in the Granite State—until now.

“It’s part of a pattern we’ve been seeing over the last ten years or so of EHD and bluetongue, which is a related disease, showing up in more and more places further north,” National Deer Association Chief Communications Officer Lindsay Thomas tells Field & Stream. “The strongest theory for this spread is that it’s related to climate change. The insect vector that spreads the virus is finding more and more tolerable temperatures further north.”

EHD does not generally have a long-term impact on deer populations, though it can seriously knock down populations in the short term, especially in places like New Hampshire. “The further north you go, the less these deer populations have historical experience with the disease. This means they have less immunity and higher mortality rates,” says Thomas. “Over time, these deer populations can bounce back, but it does take a little longer in the north because you’ve got more deer dying.”

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Deer infected with EHD suffer from high fever, dehydration, and internal hemorrhaging. They often froth at the mouth, have swollen heads, necks, and tongues, and are reluctant to move. EHD-infected deer are often found dead near or in water sources. Both the NHFG and Thomas say reporting sick and dead deer is paramount. There is nothing game agencies can do to slow the spread of the disease, but they can alter regulations to minimize population-level impacts.

“Hunters are the eyes and the ears of wildlife agencies,” says Thomas. “If you see a sick deer, don’t just take a video for social media and go ‘look at this. Ain’t this weird?’ Your first action should be to call your state wildlife agency and let them know.”