Donkeys are susceptible along with all other equines to Equine Flu. Ensure your donkeys’ inoculations are up to date, and if not we recommend you contact your vet and arrange for them to be inoculated. We also recommend that you do not move your donkeys during this outbreak nor allow new equines onto the premises, and also implement your biosecurity measures. The virus is very contagious and can be spread usually through inhalation of the virus from other infected equines, but can also be spread by people who have had contact with infected equines.
You might find this information on the Donkey Sanctuary website of use: