Schmallenberg virus is a big issue in part because it is so new. In the summer of 2011, German dairy farmers reported an illness that made their cows develop fevers and diarrhea, which affected milk production. Then in late 2011, several sheep farms in the Netherlands reported the delivery of a number of lambs with a variety of serious congenital malformations. Researchers eventually concluded that the cows and the mother sheep had been infected with a new virus of the Orthobunyavirus genus.
Subsequently the new virus has been confirmed in a number of western European countries. The schmallenberg virus, like others of its genus, is transmitted by mosquitoes and biting midges. It has traveled quickly, and control measures are being planned. Meanwhile, countries in eastern Europe as well as Russia, Mexico, Egypt, and the US have temporarily banned importation of animals and/or germplasm from the affected areas. This has been somewhat controversial, but caution is considered necessary at this point.
A second looming concern is whether this virus, which has already affected several species, can make the jump to infecting humans. Although no human cases have been reported, the Orthobunyavirus group has several other members that have been shown to be capable of infecting humans. Since the virus can cause birth defects, this is a matter of great concern at the moment.