The majority of cases have been reported in Västra Götaland, Halland, and Skåne counties, and a few isolated cases have been found in Blekinge and Kronoberg counties. Usually, a small number of animals have been affected in each herd.
The infection affects both sheep and cattle, but the greatest impact on general health has been seen in sheep.
The disease is spread through blood-sucking midges. They become inactive and stop biting when the temperature drops to around five-six degrees and die when it reaches zero degrees.
"With falling temperatures, we now see that the spread of the infection is decreasing and expect it to completely cease within the next few weeks," says state epizootologist Karl Ståhl in a press release from the National Veterinary Institute.
He believes that the spread of the infection will pick up again next year. It will likely start earlier and be more extensive then, since the infection is now more widespread.