The virus is shed in the faeces and thus transmission is horizontal, via the direct faecal-oral route and also indirectly via fomites.

Clinical disease only occurs in young geese and ducks between birth and 4–5 weeks of age.

Some signs of Derzsy's disease in geese include prostration and death in acutely affected goslings, reduced feed intake, excessive water intake, swollen eyelids, eye and nasal discharge, white diarrhea, the presence of a membrane covering the tongue, loss of down, and reddening of the skin.

Older animals tend to show severe systemic and neurological signs and diarrhoea.

[3] Good biosecurity measures should be maintained including adequate quarantine, isolation, separation of different age groups and disinfection.