Epizootic Hemhorragic Diseasein Wild White-tailed Deer

www.michigan.gov/wdm -EHD

Hemorrhagic disease is an insect transmitted viral disease of wild ruminants. It is caused by two closely related orbiviruses, the bluetongue viruses (BTV) and the epizootic hemorrhagic disease viruses (EHDV). Disease caused by these two viruses is indistinguishable and is collectively referred to as hemorrhagic disease (HD). HD has been associated with significant mortality only in North American ungulate populations.

• ETIOLOGYThe bluetongue viruses (BTV) and the epizootic hemorrhagic disease viruses (EHDV) are closely related serogroups of orbiviruses. Worldwide there are at least 24 serotypes of BTV and 10 serotypes of EHDV. Fifteen serotypes of BTV exist in the US; 2, 10, 11, 13 and 17 are considered enzootic. BTV 10, 11, 13, and 17 are known to cause disease and it is likely 1 does also. Three serotypes of EHDV (1, 2, and 6) exist in the US; all three are known to cause disease.

EHD

SUSCEPTIBLE WILDLIFE SPECIES IN U.S.

EHD

Although these viruses can infect a wide variety of ruminants, susceptibility varies among species. HD principally affects white-tailed deer and mule deer, but disease has been reported in other North American ungulates.

EHD

EPIDEMIOLOGY

EHD

HD generally occurs in late summer and early fall, probably relating to the seasonal patterns of vector activity.  This is illustrated in the graph on the left which demonstrates virus isolations made from white-tailed deer and the graph on the right which depicts the seasonal distribution of acute and chronic HD cases.

GROSS LESIONS

EHD

As the disease progresses endothelial damage and the development of disseminated intravascular coagulation lead to the development of hemorrhages. Petechial and ecchymotic (left) to suffusive hemorrhages (right) may be seen on serosal surfaces.

• GROSS LESIONS

EHD

Typical lesions are hemorrhages on the serosal surface of the pylorus and at the base of the pulmonary artery (above).

 

Severe hyperemia to hemorrhage is seen in the fore-stomachs.

EHD Die-Offs in Michigan

1955Manistee

Lake

MuskegonSaginaw

Estimate: 100 deer

Lake ManisteeMuskegonSaginaw

Estimate: 100 deer

ArenacIngham IoscoGratiotMecosta

Iosco

Arenac

Mecosta

Gratiot

Ingham

1974

EHD Die-Offs in Michigan

2006

Estimate: 50-75 deer

Allegan

Allegan

EHD Die-Offs in Michigan

2008

Estimate: 150-200 deer

Macomb Oakland

Oakland

Macomb

EHD Die-Offs in Michigan

2009

Estimate: 300-400 deer

Livingston

Livingston

EHD Die-Offs in Michigan

2010

Estimate: 1,025 deer

AlleganBerrienCassOttawaSt. JosephVan Buren

Ottawa

Allegan

Van Buren

BerrienCass St. Joseph

EHD Die-Offs in Michigan

EHD Die-Offs in Michigan

2011

Estimate: 300 deer

CassSt. Joseph

CassSt. Joseph

EHD Die-Offs in Michigan

2011

Iosco

Arenac

Mecosta

Gratiot

Ingham Oakland

MacombLivingston

Ottawa

Allegan

Van Buren

BerrienCassCass

St. Joseph

19551974

20062008

2009

2010

Manistee

Lake

MuskegonSaginaw

www.michigan.gov/dnr