[3] It has long been suspected that the disease is caused by a Sindbis-like virus, a positive-stranded RNA virus belonging to the Alphavirus genus and family Togaviridae.
[1] In 2002 a strain of Sindbis was isolated from patients during an outbreak of the Pogosta disease in Finland, confirming the hypothesis.
[4] A typical Pogosta disease patient is a middle-aged person who has been infected through a mosquito bite while picking berries in the autumn.
The prevalence of the disease is about 100 diagnosed cases every year, with larger outbreaks occurring in 7-year intervals.
The names are derived from the words Pogosta, Karelia and Ockelbo.