Bluetongue virus in wild deer, Belgium, 2005-2008

Abstract

To investigate bluetongue virus serotype 8 infection in Belgium, we conducted a virologic and serologic survey on 2,416 free-ranging cervids during 2005-2008. Infection emerged in 2006 and spread over the study area in red deer, but not in roe deer.

Figure 1

Frequency distribution of results of a competitive ELISA for detecting antibodies against bluetongue virus in serum samples from roe deer (white columns) and red deer (black columns) during the hunting seasons of A) 2005, B) 2006, C) 2007, and D) 2008, Belgium. Hunting was conducted in 30 (area 12,851 km²) of 37 (area 16,844 km²) forest districts known to contain wild cervids. The study population of wild cervids in southern Belgium (49°30′N–50°48′N) is estimated to be ≈11,000 red deer (Cervus elaphus) and ≈33,000 roe deer (Capreolus capreolus). Serum samples with a percentage negativity value (relative to the negative control serum) <66 were considered positive.

Figure 2

Distribution of red deer samples obtained in Belgium (Wallonia) in A) 2005, B) 2006, C) 2007, and D) 2008, and location of forest districts. White circles indicate districts where only seronegative animals were detected, and black circles indicate districts where seropositive animals were detected. Scale bar indicates 100 km.