Hard to guess when you haven't seen the line and the way it lays out. The line is a flowage shaped like the outline of the state of Virginia, with the western and northern borders formed from CCC ditches dug in the early1900's. On the north is a single ditch that runs straight north into a bog and stops. On the interior are three flowages that drain to these ditches, the west side drains to the west and the north and center drain to the north. While running this and cutting trails, I noticed several smaller flowages with dead lodges/ houses. The nw corner of the flowage had a series of five in a row, pond to pond all dead. Interior ponds all active, two of which had two houses on them, which contained the numbers and age class beaver they should. In the ditch in that NW section, up and downstream from the stretch with the dead houses, all the houses just had pairs of two year old beaver in them, and several old lodges along the way dead. Farthest sw house in the ditch, almost to the river was a house with a huge 4 year old pair and a set of last years pups? In short, out of the 43 beaver I've taken out of there so far, there are only 3 that are in the 3 YO class (would be 4 this May). Two of those were taken out of the same pond, and one was taken out of that ditch running straight north about a mile away from the main ditch. There are plenty of beaver still in there, but what are the odds just that year age class avoided my sets? What it's looking like to me, is that this area had a disease wipe out that ditch area in the NW about three years ago, the area has been populated again, and the interior ponds, which all drain to the ditch system weren't affected. All the real big beaver were taken out of the interior ponds , except the two with pups down near the river/ first house upstream from river. I've seen this twice before, and it seems to kill all the small beaver of one year age class. I've heard the name of the disease, it's about twenty letters long. Anybody know the name of the disease?