This should not be confused with primary central nervous system disease described in rock rattlesnakes. These are agonal signs and are rather non-specific. Snakes may twist around, become flaccid and quiet for a period of time, and initiate these death-throws all over again. Often snakes will be found dead in their cage early in the morning, having died the night before. Many of thse snakes appear to be in good health with good weight and normal behavior prior to death.
Clinical signs can be subtle or non-specific such as off feed for one to two weeks.
Although clinical signs in the earlier stages of the disease are often subtle, abnormal respiratory sounds are audible when ill snakes are manually restrained. If the oral cavity is examined, exudate may be seen within the glottal opeing. Other organs which may be involved on a gross level are the pancreas and liver. Pancreatic hyperplasia is not uncommonly encountered in infected crotalid snakes. The authors have seen this quite commonly in timber rattlesnakes, Crotalus horridus .