High temperatures over the summer are being blamed for the spread of bluetongue virus (BTV) into areas of northern Europe for the first time. BTV is a double-stranded RNA virus and a member of the Orbivirus genus. The disease, bluetongue, affects ruminants, with severe disease mainly occurring in sheep, and is transmitted by certain species of Culicoides biting midges. BTV was once confined to tropical and sub-tropical countries but was first reported in Europe in 1998 and since then outbreaks have been reported in many countries in southern Europe, including Greece and Italy. In August this year, the virus was detected in several regions of northern Europe, including areas in southeast Belgium, western Germany and the southern Netherlands. The European Commission has imposed a restriction zone in affected areas, which has been affecting trade. Testing at the UK's Institute of Animal Health (IAH) in Pirbright revealed that the serotype involved is BTV-8, a serotype that has not been seen before in Europe and which IAH experts think came from Africa. Science /BBC
The anti-tuberculosis drug isoniazid was discovered more than 50 years ago, but the determination of its precise mechanism of action has been a highly contentious area of Mycobacterium tuberculosis research. Now, reporting in Nature Medicine, Bill Jacobs and colleagues hope that they have finally pinpointed the mechanism involved. InhA, an NADH-specific enoyl–acyl carrier protein that is involved in mycolic acid biosynthesis is one of the proposed targets of isoniazid. The authors used a modified linkage-transduction method to introduce a version of inhA carrying an S94A point mutation into M. tuberculosis and found that this point mutation was sufficient to inhibit mycolic acid biosynthesis and confer clinically relevant resistance to isoniazid. The molecular mechanism of resistance conferred by the point mutation was determined by co-crystallizing InhA with a covalent isoniazid adduct, confirming InhA as the target. Nature Med.
