By Maryn McKenna
Email Author
February 7, 2012 |
4:32 pm
A newly identified disease is moving rapidly through livestock in Europe and has authorities both worried and puzzled. The disease, dubbed Schmallenberg virus for a town in west-central Germany where one of the first outbreaks occurred, makes adult animals only mildly ill, but causes lambs, kids and calves to be born dead or deformed.
The United Kingdom’s Animal Health and Veterinary Laboratories Agency (AVHLA) said today that the virus has been found on 29 farms in England; in the past few weeks they found it in sheep, but today announced that they have identified it in cattle as well. In mainland Europe, it has been identified on several hundred farms in the Netherlands, Germany and Belgium, and most recently in France. The European Center for Disease Prevention and Control has said that the new virus’s closest relatives do not cause disease in humans — but that other more distantly related viruses do:
The new virus belongs to the Bunyaviridae family, genus Orthobunyavirus, Simbu serogroup (preliminary information, based solely on genetic information)… Genetic characterisation has shown that the new virus is closest to the following Simbu serogroup viruses: Shamonda-, Aino- and Akabane-viruses, which do not cause disease in humans.
However, at least 30 orthobunyaviruses are zoonotic and may cause disease in humans, with symptoms ranging from mild to severe — e.g. La Crosse encephalitis virus, California Encephalitis virus, Cache Valley virus, Batai virus, Tahyna virus, Inkoo virus, Snowshoe Hare virus, Iquitos virus and Oropouche virus.
The viral vector — the thing which spreads it — is believed to be midges, small flying biting insects (Culicoides) and maybe also mosquitoes (Culicidae). The disease doesn’t pass from adult animal to another animal, but apparently does from a mother animal to its offspring in utero, and that is why it is showing up now: It’s lambing season. With Europe enduring its coldest winter in decades, there are no virus-carrying insects flying around now. Instead, the animals that are giving birth to deformed and dead offspring were infected last summer and fall. No one has been able to say so far whether the organism can survive in insects over the winter (the way West Nile virus, for instance, may)
more
Source: http://www.wired.com/wiredscience/2012/02/schmallenberg-virus/
