Figure 3

Finnish reindeer herding area (black) divided in 56 reindeer herding cooperatives and two wild forest reindeer populations (shaded). The foci of S. tundra associated disease [1] and S. tundra microfilaremia in reindeer blood [2] was in 2003 in the area 1, and moved northwards during next two years into the area 3, while the area 4 remained free of infection.