Bluetongue in the United States

Area of Science:

• Veterinary Virology
• Animal Disease Epidemiology

Background:

• Bluetongue virus (BT) was first isolated and identified in US sheep in California in 1952.
• A Texas sheep disease,
• soremuzzle,
• observed in 1947, showed similarities to BT, suggesting its earlier presence.
• There are 23 BT serotypes globally, with five recognized in the US (types 10, 11, 13, 17, and 2).

Purpose of the Study:

• To provide a historical overview of bluetongue virus identification and prevalence in the United States.
• To highlight the evolution of bluetongue virus recognition from a sheep-specific disease to one affecting cattle.
• To introduce the related Epizootic Hemorrhagic Disease (EHD) virus and its presence in the US.

Main Methods:

• Historical review of scientific literature and disease surveillance records.
• Serological classification of bluetongue virus serotypes.
• Documentation of disease recognition timelines and geographical spread.

Main Results:

• Bluetongue virus (BT) was first confirmed in the US in 1952, potentially present earlier in Texas.
• Five BT serotypes (10, 11, 13, 17, 2) are known in the US, with type 2 identified in Florida cattle in 1983.
• By the 1960s, BT was recognized in cattle, presenting symptoms that could be confused with other bovine diseases.
• Epizootic Hemorrhagic Disease (EHD) virus, serologically related to BT, was first identified in US deer in 1956, with two serotypes now known.

Conclusions:

• Bluetongue virus has a significant history in the US, affecting both sheep and cattle.
• The diversity of BT serotypes and its clinical presentation in cattle necessitate careful diagnosis.
• The relatedness of BT and EHD viruses underscores the importance of orbivirus surveillance in livestock and wildlife.