For example, horses may initially show signs of anorexia, excessive salivation, chewing and frequent yawning, followed by loss of control of body movements, such as involuntary eye movements, head-pressing, sleepiness, partial paralysis, and loss of balance. Those horses which recover may be suffer from effects such as loss of coordination, blindness or fluid on the brain. BDV is endemic in horse populations in Germany. It has also occurred in the Near East, other parts of Central Europe, the United States, Japan, Sweden, Israel and Syria. However, not all infected animals show clinical signs.
Some horses go through periods of apathy, energy loss and sleepiness before recovering completely.
Infected cats can stagger and act depressed and apathetic before recovering on their own. There are also indications that it may be spread in the animal's uterus to its offspring. The virus is not transmitted by eggs, meat and meat products. At this stage, there is no vaccine to prevent BDV, nor is there any effective treatment. However, the work carried out by AgResearch in isolating the WPD virus may assist in this if the two diseases are in fact related.