Bluetongue: Vector surveillance in Austria in 2007

Area of Science:

• Veterinary Entomology
• Arthropod-borne Diseases
• Public Health Surveillance

Background:

• Bluetongue disease (BTD), caused by bluetongue virus (BTV), is an infectious disease affecting livestock and wild ruminants, originating in South Africa.
• BTV is transmitted by biting midges of the genus Culicoides, with several species implicated in European transmission.
• Austria has historically been free of BTD, but recent outbreaks in neighboring countries necessitate surveillance.

Purpose of the Study:

• To conduct vector surveillance for potential bluetongue virus (BTV) transmitters in Austria.
• To identify the predominant Culicoides species present in Austria and assess their potential role in BTV transmission.
• To establish baseline data for future BTD risk assessment and management in Austria.

Main Methods:

• Deployment of 50 blacklight traps across Austria from June to December 2007.
• Weekly collection and identification of Culicoides specimens.
• Assignment of collected specimens to species complexes (Obsoletus, Pulicaris, Nubeculosus) or other categories.

Main Results:

• Over 1.5 million Culicoides specimens were collected.
• The Obsoletus complex constituted the vast majority (87.3%) of collected specimens.
• The Pulicaris complex (6.7%) and Nubeculosus complex (0.1%) were also identified.
• Peak Culicoides populations were observed in July and August, with a decline in October.

Conclusions:

• The Obsoletus complex represents the most abundant potential vector for bluetongue virus (BTV) in Austria.
• Seasonal abundance of Culicoides suggests higher transmission risk during summer months.
• Ongoing vector surveillance is crucial for monitoring BTV introduction and spread in Austria.