Bluetongue virus serotype 8-associated hydranencephaly in two calves in south-eastern England

Developmental lesions of the central nervous system (CNS) have been described associated with transplacental infection with bluetongue virus (BTV) in cattle (MacLachlan and others 1985) and sheep (Osburn 1972). In the past, the development of these deformations was mostly associated with laboratory-adapted BTV strains, in particular live attenuated vaccine virus strains (Schultz and Delay 1955, Kirkland and Hawkes 2004). However, in 2008, reports from northern European countries revealed an upsurge of similar CNS lesions in calves and lambs following the infection of pregnant cows and ewes with a field strain of BTV serotype 8 (Desmecht and others 2008, Vercauteren and others 2008, Wouda and others 2008). This short communication describes the clinical, virological and pathological findings in two calves born in England during 2008 to cows infected with BTV while pregnant in autumn 2007, and reports bluetongue-associated hydranencephaly, with an affected 'dummy' calf surviving until seven months old.