Epizootic Hemorrhagic Disease

By Dr. Susan Muller Esneault

Filed Under: Cows, Diseases

The weather is so beautiful that you decide to take a hike along a stream or small river and you come across a deceased white-tailed deer in or around the water.  Unfortunately, it is not an uncommon scenario.  Epizootic hemorrhagic disease or EHD is a viral disease of white-tailed and mule deer that is spread by biting gnats.  Domestic ruminants such as cattle and sheep are typically asymptomatic carriers of the virus but occasionally cattle will exhibit clinical disease.  
 
In warm dry weather gnats and deer congregate near watering holes.  These gnats are actually of the Culicoides species, which are biting flies, or midges.  The virus is not transmitted directly between deer but rather through the Culicoides species which pick up the virus from one deer and inoculates the virus into another.   
 
The spread of the disease can be stopped by the first frost which will kill the disease-carrying gnats.  It also tends to spread the deer over a wider geographical area, thereby limiting their exposure to the virus. 
 
The incubation period for the virus is five to ten days.  The first signs of disease may include disorientation, lameness or unresponsive behavior to the presence of humans.  These animals are lethargic and may have a bloody discharge from their nose; they often develop lesions or sores on the mouth, salivate excessively, and may develop a swollen, blue tongue.  The deer may appear emaciated because they will stop eating and even drinking, although they congregate near water.  Eight to 36 hours following the onset of clinical signs, deer pass into a shock-like state, become prostrate, and die.
 
The morbidity of EHD can reach a 90% level with a mortality rate of around 60%. making this Orbivirus one of the most important viral diseases of deer.
 
The disease may be confirmed through viral isolation or serologic monitoring.   
 
 
References. 
 
http://wdfw.wa.gov/factshts/ehd.htm
 
http://www.michigan.gov/dnr/
 
http://www.vet.ohio-state.edu/3160.htm
 
Radostits, Otto, and Clive Gay.  Veterinary Medicine.  10th Edition. P. 1305.

Topics: viruses

»

Similar entries

  • Bovine Viral Diarrhea Virus, or BVDV

    Did you know that “Bovine Viral Diarrhea” is actually an all-inclusive term for a clinical disease manifestation that potentially involves one or two distinct viruses? Two distinct biotypes of the virus, two viral states of infection and five distinct clinical forms of acute disease are seen with the Bovine Viral Diarrhea Virus (BVDV). This complex is also known as “Bovine Virus Diarrhea”, “Mucosal Disease”, or “Bovine Pestivirus Disease Complex”.

  • Chronic Wasting Disease of Elk and Deer

    First reported in the late 1960’s in captive mule deer found in Colorado, Chronic Wasting Disease (CWD) has now been found in cervids (hoofed ruminant mammals whose males of the species have horns) in much of the northwestern United States and several Canadian provinces.  Surveillance studies in hunter-harvested animals from 1996-1999 found that CWD infected approximately 5% of the mule deer, 2% of the white-tailed deer, and <1% of the elk in the Colorado and Wyoming areas of the United States.  The geographical area and number of animals infected continues to grow. 

  • Malignant Catarrhal Fever or Bovine Malignant Catarrh

    Malignant Catarrhal Fever (MCF) or Bovine Malignant Catarrh are actually two diseases caused by separate herpes viruses that are almost always fatal to cattle, deer, bison, occasionally pigs, rabbits, and certain exotic ruminants. Neither virus causes disease in their principal hosts, either the wildebeest or the sheep.

  • Rift Valley Fever

    Endemic to Madagascar, eastern, and southern Africa is an RNA disease causing virus named for the area in which it was first reported in 1930 called Rift Valley Fever (RVF). The virus has since been detected as far north as Egypt and over to the Arabian Peninsula countries of Saudi Arabia and Yemen. Although an important pathogen in its native area affecting domestic ruminants and people, RVF is feared as a potential biological weapon capable of spreading the globe by the movement of infected people, animals, and insects.

  • Canine Flu or Canine Influenza Virus (CIV)

    Think your dog may have a bad case of Infectious Tracheobronchitis? You may not be dealing with a run-of-the-mill kennel cough. Canine Influenza 1 virus, or CIV, has become an important emerging infectious disease in dogs. The virus responsible for the condition is H3N8 influenza A virus.