December 01, 2012Most Michigan deer hunters are well aware that epizootic hemorrhagic disease (EHD) has reared its ugly head at historic levels in Michigan this year.
A viral disease that it transmitted by the bite of a fly called a midge, EHD causes deer to die from internal bleeding. It has been found in 30 counties in Michigan this year, mostly in the southern third of the state, though it has been documented in Clare and Osceola counties and is suspected as far north as Presque Isle and Benzie counties. This is the largest, most widespread outbreak of the disease in Michigan history.
First described in Michigan in 1955, EHD wasn't seen again until 1974 and then not again until after the turn of the century. Since 2006, however, it has occurred at some level every year except 2007.
Deer with epizootic hemorrhagic disease (EHD), now reported in 30 counties throughout Michigan, develop weakness, excessive salivation, rapid pulse and respiration rate, fever and eventual unconsciousness. Most deer seek out a body of water to try to cool themselves. Michigan's deer population is experiencing its widest outbreak ever of epizootic hemorrhagic disease (EHD).
EHD is widespread across the Midwest this year, something that is thought to have been caused by last winter's unusually mild weather as well as this year's drought. The tiny flies (about one-tenth of an inch in length) that carry EHD typically breed in mud flats, and this summer's drought has expanded areas where midges of the genus Culicoides can reproduce. In most years, those mud flats would be underwater.
"Other states around us – Indiana, Illinois and Ohio – have seen this more frequently, and some of them have it from one end of the state to the other," explained Brent Rudolph, the deer and elk program leader for the Department of Natural Resources. "In Michigan, it's been mostly restricted to the southern third of the state, though we've had a couple of cases that bounced up above the line."
Rudolph said that states from South Dakota to Kansas have reported more widespread mortality this year than ever before. Deer with EHD suffer from high fevers and head toward water to seek relief. Their bodies are often found in or near ponds, rivers or creeks.
EHD tends to be highly localized; in some cases the disease causes large die-offs in part of a township while areas just a few miles away show no sign of the disease.
Often referred to by hunters as "blue tongue" – a similar, though different disease – EHD shows up in the herd in the summer months, after regulations have been developed for the upcoming hunting season.
The DNR has no estimate of total EHD mortality, though it has had more than 13,000 dead deer reported.
Rudolph said that EHD has never caused widespread or long-term impacts to deer populations, though local effects can be significant and can last for a few years.
"Until this year, we've never seen enough EHD in Michigan to cause population declines at a broad scale, but the southwestern corner of the state – Cass and St. Joseph counties – has had EHD a couple of years in a row, in 2010 and 2011, and now again this year," he said.
Because of this trend, DNR Director Keith Creagh today signed an emergency order that decreases antlerless license purchase limits for deer management units (DMUs) where the most EHD-related die-offs have occurred. Director Creagh signed the order at the regular monthly meeting of the Natural Resources Commission.
Effective immediately, the purchase limit for DMU 486 is five private land antlerless deer hunting licenses per hunter. Also effective immediately, the public antlerless license purchase limit per hunter is two for each of the following DMUs: 012 (Branch), 034 (Ionia), 039 (Kalamazoo), 041 (Kent), 044 (Lapeer), 076 (Sanilac), 078 (Shiawassee), 079 (Tuscola) and 080 (Van Buren).
Individuals who purchased antlerless licenses prior to this emergency order are not required to return licenses. This order only applies to antlerless licenses purchased on or after Nov. 8, 2012.
"We're encouraging hunters to use their best judgment," Rudolph said. "If a hunter is in an area of an outbreak, backing off – or not taking an antlerless deer at all – is an appropriate thing to do."
From the information that was received from numerous volunteers, a weekly EHD map has been compiled, which may help aid hunters with their harvest decisions. The map and other EHD information including how hunters can report sighting of deer can be found at www.michigan.gov/wildlifedisease (under Current Issues).