Epizootic hemorrhagic disease

Last updated

Epizootic hemorrhagic disease (EHD) is a hemorrhagic disease of white-tailed deer (Odocoileus virginianus) caused by an infection of a virus from the genus Orbivirus subsequently called Epizootic hemorrhagic disease virus (EHDV). [1] [2] It is an infectious, and sometimes fatal, virus that is characterized by extensive hemorrhages, and is found throughout the United States. Large-scale outbreaks in wild ruminants affect livestock and the production industry. [3] EHD has been found in some domestic ruminants and many species of deer including white-tailed deer, mule deer, elk, and pronghorn antelope. [4] Seropositive black-tailed deer, fallow deer, red deer, wapiti, and roe deer have also been found, which essentially means that they were exposed to the disease at some time in the past but may not be involved in transmission. Outbreaks of EHD have been reported in cattle, although they rarely develop disease or die. Sheep may develop clinical signs, but this is also rare. [2] EHD is often called bluetongue, but this is incorrect. Bluetongue virus is closely related to EHDV, and has similar clinical signs, but it is a different disease. Bluetongue is a serious disease in cattle, as well as other ruminants, and can have a significant effect on international trade. Testing at animal health laboratories is necessary to distinguish between the viruses that cause bluetongue and EHD.

Contents

Geographic distribution

The distribution of EHD depends greatly on the distribution and abundance of the biting midge ( Culicoides variipennis ), the level of existing immunity in deer, and the genetic variations in susceptibility. [5] EHD is found in North America, Australia, Asia, the Middle East and Africa. [6] Seropositive animals have also been found in South America. It occurs most often in the Southern United States, although its distribution is not uniform. [7] In the south, the disease is characterized as frequent and mild, whereas in the north, the disease is characterized as infrequent, severe, and capable of high mortality. [5] Researchers in 2003 found that fawns of northern subspecies of white-tailed deer infected with EHDV developed severe clinical symptoms while southern subspecies had mild or nondetectable disease suggesting geographic differences in innate resistance or maternal antibodies. [7] Researchers also found that maternal antibodies against EHDV could be detected in Georgia deer up to 18 weeks, and seropositive fawns showed minimal clinical evidence of disease while seronegative fawns exhibited mild to moderate clinical signs of disease. [8] EHD can occur throughout Indiana and other parts of the midwestern United States where the disease can be characterized by both significant outbreaks that occur on a 5- to 10-year cycle that affect the entire state and smaller outbreaks that may only involve a few counties.

Transmission

Transmission of EHD occurs by a host being bitten by a virus-carrying fly or midge. Many different species of culicoides can carry this virus, but the most common carrier is thought to be Culicoides variipennis. EHD can only be transmitted by a vector, meaning it cannot be transmitted from animal to animal, but only through the initial bite by a vector. Ordinarily, EHD outbreaks reoccur within an area primarily during seasonal dry spells. Outbreaks typically result in large die-offs, and smaller and more isolated outbreaks can be common. [9]

The midge larvae hatch and live near the water's edge in the bank. They grow and typically remain in the submerged mud in water that is less than 2 inches deep. They continue to live in eutrophic areas, as these areas provide the highest likelihood of survival for the larvae and the midge as it matures. The midges do not survive long after the first seasonal frost. [9]

Clinical signs

Deer may become infected with peracute, acute, or chronic EHD infections. They can develop clinical signs in as few as 7 days after exposure, and this is most constantly characterized by sudden onset of the disease. In general, deer infected with EHD lose their appetite, lose their fear of people, grow weak, show excessive salivation, develop a rapid pulse, have a rapid respiration rate, show signs of a fever, which includes lying in bodies of water to reduce their body temperature, become unconscious, and have a blue tongue from the lack of oxygen in the blood. [2] The heads and necks of infected deer may swell. One of the most common characteristics of deer with the chronic form of EHD is the sloughing or breaking of the hooves caused by growth interruptions. Deer with chronic EHD often become lame due to these hoof problems. [4] Although they are ill for several weeks, they can eventually recover. Deer with the peracute form of the disease may go into shock 8–36 hours after the onset of symptoms, and are found lying dead. [2] Death is also common in deer with acute EHD, which is generally comparable to peracute EHD and is characterized by excessive salivation, nasal discharge, and hemorrhaging of the skin. [4] Cattle that develop EHD typically have subclinical signs. These infections are less severe than the infections in deer, but they may still exhibit fever, oral ulcers, excessive salivation, lameness, and coronitis (inflammation of the coronary band in hoofed animal). Sheep rarely develop clinical signs, and experimentally infected goats have never been shown to exhibit any signs of EHD. [4] Typically, EHD does not kill livestock, but it may affect the production industry negatively because of effects from the disease such as cattle weight loss and lameness.

Prevention and control

Protection of livestock stables

Reducing midges around livestock stables is a good way of reducing the likelihood of disease transmission. To “midge-proof” a stable, several precautions must be taken. One way to reduce entry of midges into the stable is to add screens with very fine mesh. Although mesh significantly reduces the entrance of midges, it is not 100% “midge-proof” on its own. [10] In addition to the mesh screen, fans can be placed strategically in the stable. Fans are effective in reducing midges because of their small size and poor flying capabilities. [11] Removing breeding pools around livestock is also essential. Midges can breed in pools as small as a hoofprint. Providing a substrate that is well-drained and resists the formation of pools can prevent midges from breeding.

Consumption of Infected Animals

EHD has been shown to not affect humans, and no evidence has been found that the epizootic hemorrhagic disease can be contracted through midge bites or by consuming venison that has been infected with the virus. EHD is exclusive to ruminants, and no cases have been reported of nonruminants exhibiting signs or symptoms that are linked to EHD. [12] Once EHD is contracted, the likelihood of other diseases being contracted increases. As a result of the additional exposure to other infections, consuming venison from animals that are visibly sick is not recommended. Animals that are sick may show obvious signs of extreme fatigue and illness, such as rapid weight loss or lesions or abscesses across the body. Other signs include foaming or frothing of the nose and mouth (similar to rabies), as well as the decay of walls of their hooves. [13]

Farmed or captive deer

Currently, no vaccines for EHD are available. Spraying land with insecticides or larvicides could also decrease the risk of transmission.[ citation needed ]

Management of breeding sites

Because midges breed in water, management of breeding sites is the best way to reduce their numbers, though this may not be practical in areas with lakes or ponds. However, preventive actions include stopping troughs from overflowing, making sure pipes are not leaking, and removing any standing pools of water. [10] Reducing standing water greatly reduces midge populations in a given area.

History

Epizootic hemorrhagic disease has been around for many years. EHD is thought to have been first found and tracked back to around 1890, and has been responsible for die-offs of many different species across North America. Diseases such as blackleg, blacktongue, bluetongue, mycotic stomatitis, or hemorrhagic septicemia were thought to have been the cause of many of these die-offs. After further analysis, the true causative agent was never confirmed. After further review of the case history and other telltale signs and lesions, seasonal occurrence, and lack of a bacterial agent suggest that they might have been EHD. [14] Current research is focused on the elucidation of mechanisms governing differences in response to EHDV among populations of white-tailed deer. Direct experiments have suggested that regional differences in response to EHDV may be tied to differences in maternal antibodies and innate resistance to EHDV between northern and southern subspecies of deer. [8] [7] Researchers in 2023 found that two single nucleotide polymorphisms had significant differences in frequency between EHD-positive and EHD-negative deer, suggesting a genetic component in susceptibility to EHDV. [15]

Related Research Articles

<span class="mw-page-title-main">Bluetongue disease</span> Viral disease in animals

Bluetongue disease is a noncontagious, insect-borne, viral disease of ruminants, mainly sheep and less frequently cattle, yaks, goats, buffalo, deer, dromedaries, and antelope. It is caused by Bluetongue virus (BTV). The virus is transmitted by the midges Culicoides imicola, Culicoides variipennis, and other culicoids.

<span class="mw-page-title-main">Q fever</span> Coxiella burnetii infection

Q fever or query fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including cats and dogs. The infection results from inhalation of a spore-like small-cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick-borne. The incubation period can range from 9 to 40 days. Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite.

<span class="mw-page-title-main">Chronic wasting disease</span> Prion disease affecting the deer family

Chronic wasting disease (CWD), sometimes called zombie deer disease, is a transmissible spongiform encephalopathy (TSE) affecting deer. TSEs are a family of diseases thought to be caused by misfolded proteins called prions and include similar diseases such as BSE in cattle, Creutzfeldt–Jakob disease (CJD) in humans and scrapie in sheep. Natural infection causing CWD affects members of the deer family. In the United States, CWD affects mule deer, white-tailed deer, red deer, sika deer, elk, caribou, and moose. Experimental transmission of CWD to other species such as squirrel monkeys and genetically modified mice has been shown.

Classical swine fever (CSF) or hog cholera is a highly contagious disease of swine. It has been mentioned as a potential bioweapon.

<span class="mw-page-title-main">White-tailed deer</span> Species of hooved mammal

The white-tailed deer, also known commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, Central America, and South America as far south as Peru and Bolivia, where it predominately inhabits high mountain terrains of the Andes. It has also been introduced to New Zealand, all the Greater Antilles in the Caribbean, and some countries in Europe, such as the Czech Republic, Finland, France, Germany, Romania and Serbia. In the Americas, it is the most widely distributed wild ungulate.

<span class="mw-page-title-main">Mule deer</span> Deer indigenous to western North America

The mule deer is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer.

Parelaphostrongylus tenuis is a neurotropic nematode parasite common to white-tailed deer, Odocoileus virginianus, which causes damage to the central nervous system. Moose, elk, caribou, mule deer, and others are also susceptible to the parasite, but are aberrant hosts and are infected in neurological instead of meningeal tissue. The frequency of infection in these species increases dramatically when their ranges overlap high densities of white-tailed deer.

<span class="mw-page-title-main">Oropouche fever</span> Medical condition

Oropouche fever is a tropical viral infection transmitted by biting midges and mosquitoes from the blood of sloths to humans. This disease is named after the region where it was first discovered and isolated at the Trinidad Regional Virus Laboratory in 1955 by the Oropouche River in Trinidad and Tobago. Oropouche fever is caused by a specific arbovirus, the Oropouche virus (OROV), of the Bunyaviridae family.

<i>Orbivirus</i> Genus of viruses

Orbivirus is a genus of double-stranded RNA viruses in the family Reoviridae and subfamily Sedoreovirinae. Unlike other reoviruses, orbiviruses are arboviruses. They can infect and replicate within a wide range of arthropod and vertebrate hosts. Orbiviruses are named after their characteristic doughnut-shaped capsomers.

African horse sickness (AHS) is a highly infectious and often fatal disease caused by African horse sickness virus. It commonly affects horses, mules, and donkeys. It is caused by a virus of the genus Orbivirus belonging to the family Reoviridae. This disease can be caused by any of the nine serotypes of this virus. AHS is not directly contagious, but is known to be spread by insect vectors.

<span class="mw-page-title-main">Bovine malignant catarrhal fever</span> Species of virus

Bovine malignant catarrhal fever (BMCF) is a fatal lymphoproliferative disease caused by a group of ruminant gamma herpes viruses including Alcelaphine gammaherpesvirus 1 (AlHV-1) and Ovine gammaherpesvirus 2 (OvHV-2) These viruses cause unapparent infection in their reservoir hosts, but are usually fatal in cattle and other ungulates such as deer, antelope, and buffalo. In Southern Africa the disease is known as snotsiekte, from the Afrikaans.

<span class="mw-page-title-main">Rabbit hemorrhagic disease</span> Disease that affects wild and domestic rabbits

Rabbit hemorrhagic disease (RHD), also known as viral hemorrhagic disease (VHD), is a highly infectious and lethal form of viral hepatitis that affects European rabbits. Some viral strains also affect hares and cottontail rabbits. Mortality rates generally range from 70 to 100 percent. The disease is caused by strains of rabbit hemorrhagic disease virus (RHDV), a lagovirus in the family Caliciviridae.

Mycoplasma ovipneumoniae is a species of Mycoplasma bacteria that most commonly inhabits and affects ovine animals, first described in 1972. M. ovipneumoniae contributes to harmful pneumonia in sheep and goats. The duration and severity of M. ovipneumoniae varies from region to region.

<i>Culicoides</i> Genus of biting midges

Culicoides is a genus of biting midges in the family Ceratopogonidae. There are over 1000 species in the genus, which is divided into many subgenera. Several species are known to be vectors of various diseases and parasites which can affect animals. The genus has a long fossil record, with earliest known fossils being from Burmese amber, around 99 million years old.

Dr. Simon Carpenter, Head of the Entomology and Modelling Group in the Vector-borne Diseases Programme at the UK Biotechnology and Biological Sciences Research Council Institute for Animal Health’s Pirbright Laboratory in Woking, Surrey, is an entomologist who was awarded the first Rooker Prize in 2009 in recognition of his research on biting midges that transmit bluetongue virus (BTV), the causative agent of bluetongue disease, an important orbivirus disease of ruminants.

<i>Equine encephalosis virus</i> Species of virus

Equine encephalosis virus (EEV) is a species of virus the Orbivirus genus, and a member of the Reoviridae family, related to African horse sickness virus (AHSV) and Bluetongue virus (BTV).

Culicoides variipennis is a 1 millimetre (0.039 in) long biting midge. It is a part of the subgenus Monoculicoides and has many subspecies. Found in North America, C. variipennis transmits Bluetongue virus, African horse sickness virus, akabane virus, and epizootic hemorrhagic disease.

<span class="mw-page-title-main">Deer cutaneous fibroma</span> Disease of deer

Cutaneous fibromas are common neoplasms occurring in wild and domestic deer of many species and are caused by host-specific viral infections. The fibromas occur most frequently in animals under 2 years of age, with cases in older deer reported occasionally or rarely.

Cache Valley orthobunyavirus (CVV) is a member of the order Bunyavirales, genus Orthobunyavirus, and serogroup Bunyamwera, which was first isolated in 1956 from Culiseta inornata mosquitos collected in Utah's Cache Valley. CVV is an enveloped arbovirus, nominally 80–120 nm in diameter, whose genome is composed of three single-stranded, negative-sense RNA segments. The large segment of related bunyaviruses is approximately 6800 bases in length and encodes a probable viral polymerase. The middle CVV segment has a 4463-nucleotide sequence and the smallest segment encodes for the nucleocapsid, and a second non-structural protein. CVV has been known to cause outbreaks of spontaneous abortion and congenital malformations in ruminants such as sheep and cattle. CVV rarely infects humans, but when they are infected it has caused encephalitis and multiorgan failure.

Epizootic hemorrhagic disease virus, often abbreviated to EHDV, is a species of the genus Orbivirus, a member of the family Reoviridae. It is the causative agent of epizootic hemorrhagic disease, an acute, infectious, and often fatal disease of wild ruminants. In North America, the most severely affected ruminant is the white-tailed deer, although it may also infect mule deer, black-tailed deer, elk, bighorn sheep, and pronghorn antelope. It is often mistakenly referred to as “bluetongue virus” (BTV), another Orbivirus that like EHDV causes the host to develop a characteristic blue tongue due to systemic hemorrhaging and lack of oxygen in the blood. Despite showing clinical similarities, these two viruses are genetically distinct.

References

  1. ↑ Shope RE, Macnamara LG, Mangold R (January 1960). "A virus-induced epizootic hemorrhagic disease of the Virginal white-tailed deer (Odocoileus virginianus)". The Journal of Experimental Medicine. 111 (2): 155–170. doi:10.1084/jem.111.2.155. PMC   2137250 . PMID   19867168.
  2. 1 2 3 4 Howarth EW, Stalknecht DE, Kirkland PD (2001). "Bluetongue, Epizootic Hemorrhagic Disease, and other Orbivirus-related diseases.". In Williams ES, Baker IK (eds.). Infectious Diseases of Wild Mammals (third ed.). Ames, Iowa, USA: Iowa State University Press. pp. 77–97.
  3. ↑ "Epizootic Hemorrhagic Disease (EHD) in White-tailed Deer from the On-line Michigan Wildlife Disease Manual". Michigan Department of Natural Resources. Retrieved 2013-07-19.
  4. 1 2 3 4 "Diseases Caused by the Epizootic Hemorrhagic Disease Virus Serogroup" (PDF). Center for Food Security and Public Health. Institute for International Cooperation in Animal Biologics. 2006.
  5. 1 2 Gaydos JK, Crum JM, Davidson WR, Cross SS, Owen SF, Stallknecht DE (July 2004). "Epizootiology of an epizootic hemorrhagic disease outbreak in West Virginia". Journal of Wildlife Diseases. 40 (3): 383–393. doi: 10.7589/0090-3558-40.3.383 . PMID   15465704.
  6. ↑ "Diseases Caused by the Epizootic Hemorrhagic Disease Virus Serogroup" (PDF). Center for Food Security and Public Health. Iowa State. Retrieved 23 October 2022.
  7. 1 2 3 Gaydos JK, Davidson WR, Elvinger F, Mead DG, Howerth EW, Stallknecht DE (October 2002). "Innate resistance to epizootic hemorrhagic disease in white-tailed deer". Journal of Wildlife Diseases. 38 (4): 713–719. doi: 10.7589/0090-3558-38.4.713 . PMID   12528437. S2CID   20621327.
  8. 1 2 Stilwell NK, Clarke LL, Howerth EW, Kienzle-Dean C, Fojtik A, Hollander LP, et al. (January 2021). "The Effect of Maternal Antibodies on Clinical Response to Infection with Epizootic Hemorrhagic Disease Virus in White-Tailed Deer (Odocoileus virginianus) Fawns". Journal of Wildlife Diseases. 57 (1): 189–193. doi:10.7589/jwd-d-20-00001. PMID   33635998. S2CID   231578950.
  9. 1 2 Thomas Jr L (20 March 2013). "Can We Prevent EHD?". Quality Deer Management Association (QDMA). Archived from the original on 8 February 2018. Retrieved 22 August 2017.
  10. 1 2 Carpenter S, Mellor PS, Torr SJ (September 2008). "Control techniques for Culicoides biting midges and their application in the U.K. and northwestern Palaearctic". Medical and Veterinary Entomology. 22 (3): 175–187. doi:10.1111/j.1365-2915.2008.00743.x. PMID   18816267. S2CID   23623615. Open Access logo PLoS transparent.svg
  11. ↑ Hendrix CM. "Biting Midges - Integumentary System - Merck Veterinary Manual". Merck Veterinary Manual. Retrieved 2017-11-05.
  12. ↑ Durkin P (18 December 2014). "Facts About Bluetongue and EHD". Grand View Outdoors. Archived from the original on 6 September 2015.
  13. ↑ Adams K (2 July 2012). "Know the Signs of HD: Hemorrhagic Disease". Quality Deer Management Association (QDMA). Archived from [httep://www.qdma.com/know-signs-hd-hemorrhagic-disease/ the original] on 6 March 2018.
  14. ↑ "Epizootic Hemorrhagic Disease (EHD) in White-Tailed Deer". DNR Wildlife & Habitat Wildlife Disease. Michigan Department of Natural Resources. Archived from the original on 27 January 2012.
  15. ↑ Wessels JE, Ishida Y, Rivera NA, Stirewalt SL, Brown WM, Novakofski JE, et al. (February 2023). "The Impact of Variation in the Toll-like Receptor 3 Gene on Epizootic Hemorrhagic Disease in Illinois Wild White-Tailed Deer (Odocoileus virginianus)". Genes. 14 (2): 426. doi: 10.3390/genes14020426 . PMC   9956177 . PMID   36833353.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.