Orbiviruses: A North American Perspective

Abstract

Orbiviruses are members of the Reoviridae family and include bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). These viruses are the cause of significant regional disease outbreaks among livestock and wildlife in the United States, some of which have been characterized by significant morbidity and mortality. Competent vectors are clearly present in most regions of the globe; therefore, all segments of production livestock are at risk for serious disease outbreaks. Animals with subclinical infections also serve as reservoirs of infection and often result in significant trade restrictions. The economic and explicit impacts of BTV and EHDV infections are difficult to measure, but infections are a cause of economic loss for producers and loss of natural resources (wildlife). In response to United States Animal Health Association (USAHA) Resolution 16, the US Department of Agriculture (USDA), in collaboration with the Department of the Interior (DOI), organized a gap analysis workshop composed of international experts on Orbiviruses. The workshop participants met at the Arthropod-Borne Animal Diseases Research Unit in Manhattan, KS, May 14-16, 2013, to assess the available scientific information and status of currently available countermeasures to effectively control and mitigate the impact of an outbreak of an emerging Orbivirus with epizootic potential, with special emphasis given to BTV and EHDV. In assessing the threats, workshop participants determined that available countermeasures are somewhat effective, but several weaknesses were identified that affect their ability to prevent and control disease outbreaks effectively.

Bluetongue and Epizootic Hemorrhagic Disease in the United States of America at the Wildlife–Livestock Interface

“…Both EHDV and BTV are members of the genus Orbivirus , family Reoviridae that affect domestic and wild ruminant species around the world [ 45 , 46 , 47 ]. They are linear double-stranded RNA (dsRNA) viruses with characteristic non-enveloped, icosahedral virion morphology, and structure [ 15 , 19 ]. While not all orbiviruses cause severe disease in animals, BTV and EHDV are the most responsible for outbreaks of economic and ecological impacts on domestic and wild ruminants.…”

“…By 1902, James Spreull had provided a description of bluetongue disease (also known at the time as Malarial Catarrhal Fever) affecting sheep in South Africa [ 11 ], and by 1905, Arnold Theiler demonstrated BT’s viral etiology [ 12 ]. By the end of the 1940s, epizootics of BT in sheep in western Texas were reported [ 13 ], and in 1952, the first isolation of BTV (serotype 10) was reported from sheep in California ( Figure 1 ) [ 14 , 15 ]. By 1955, the viral etiology of EHD was first shown and the first EHDV serotype was identified and categorized as EHDV-1 (New Jersey strain) [ 16 , 17 ].…”

First molecular and serological detection of Epizootic Hemorrhagic Disease virus in white tailed deer ( Odocoileus virginianus ) from Tamaulipas, Mexico

“…Mexico falls within the predicted global range of EHDV between latitudes 35°S and 49°N (McVey et al, 2015). But, Savini et al (2011) reported the infection status of Mexico as unknown.…”

“…There are seven EHDV serotypes recognized worldwide (Ruder et al, 2015a), and EHD is considered one of the most important infectious diseases of WTD (Stallknecht et al, 2015). However, recent epidemiological shifts have increased the concern of livestock producers in North America for EHD (Breard et al, 2013;McVey et al, 2015;Stevens et al, 2015).…”

Epizootic Hemorrhagic Disease in White-Tailed Deer, Canada

“…These viruses have a historical geographic range of 40°N–50°N and 35°S, following the distribution of the Culicoides vectors. However, the epidemiology of these pathogens is changing, with decades of northward expansion into areas of Europe and North America with immunologically naive hosts ( 1 – 3 ).…”