Emergence of Bluetongue Serotypes in Europe, Part 2: The Occurrence of a BTV-11 Strain in Belgium

• Published in: Transboundary and emerging diseases Vol. 56; no. 9-10; pp. 355 - 361
• Main Authors: De Clercq, K, Mertens, P, De Leeuw, I, Oura, C, Houdart, P, Potgieter, A.C, Maan, S, Hooyberghs, J, Batten, C, Vandemeulebroucke, E, Wright, I.M, Maan, N, Riocreux, F, Sanders, A, Vanderstede, Y, Nomikou, K, Raemaekers, M, Bin-Tarif, A, Shaw, A, Henstock, M, Bréard, E, Dubois, E, Gastaldi-Thiéry, C, Zientara, S, Verheyden, B, Vandenbussche, F
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-12-2009; Blackwell Publishing Ltd; Hindawi Limited; Wiley-Blackwell
• Subjects: Animal diseases; Animals; Antibodies, Viral - blood; Belgium; Belgium - epidemiology; Blood tests; bluetongue; Bluetongue - blood; Bluetongue - epidemiology; Bluetongue - virology; Bluetongue virus; Bluetongue virus - classification; Bluetongue virus - genetics; BTV-11; Cattle; cattle diseases; Cattle Diseases - blood; Cattle Diseases - epidemiology; Cattle Diseases - virology; complementary DNA; Cross-Sectional Studies; Dairying; disease prevalence; emerging diseases; Female; Life Sciences; modified live vaccine strain; molecular sequence data; nucleotide sequences; Population Surveillance; Pregnancy; Pregnancy Complications; real-time RT-PCR; reverse transcriptase polymerase chain reaction; Ribonucleic acid; RNA; RNA, Viral; Seasons; serotypes; Sheep; Viruses; Belgium; REAL-TIME RT-PCR; MODIFIED LIVE VACCINE STRAIN; BLUETONGUE VIRUS; BTV-11
• ISSN: 1865-1674; 1865-1682
• DOI: 10.1111/j.1865-1682.2009.01092.x

An EDTA-blood sample from a cow without clinical signs, which gave early birth to a newborn calf that died soon after delivery, was shown to be positive for bluetongue virus (BTV)-RNA using a group-specific real-time RT-PCR (RT-qPCR). In-house serotype-specific RT-qPCR assays for bluetongue virus serotype 1 (BTV-1), -6 and -8 all gave negative results. Subsequent assays were carried out using conventional (gel-based) RT-PCR primers for all 25 BTV serotypes and only two primer sets, both specific for BTV-11, gave bands of the expected size. The cDNAs generated were sequenced and comparisons of the genome segment 2 sequence with that of the modified 'live' vaccine strain of BTV-11 from South Africa showed 100% identity. A survey of all ruminants in a 1-km area around the first positive farm using a BTV-11 serotype-specific RT-qPCR revealed five other holdings with in total nine BTV-11 positive animals. A cross-sectional monitoring of dairy cattle in Belgium showed an overall prevalence of 3.8% on herd level and 0.2% on animal level. A BTV-11 has been introduced into the Belgian cattle herd during the 2008 vector season. The source of the infection and the way by which the virus was introduced are unknown.