EN
Derzsy’s disease is a common disease of waterfowl poultry. The etiological agent of the disease is the goose parvovirus (GPV), also called Derzsy’s disease virus (DDV), that belongs to Parvoviridae family. The genome of the virus is represented by single stranded DNA about 5106 nt long with a molecular density of 1.38 g/ml. The disease occurs among domestic and wild geese as well as Mullard and Barbarie ducks. The GPV infection is spread horizontally through feces excreted by infected birds. There are no reliable data about transmission through the respiratory and conjunctiva route. The disease’s progress and symptoms depend on the age of birds and their immunological status. The incubation period of the disease is approximately 5 days in the case of fully susceptible 1-7-day-old goslings and the course of the disease is acute. Among older goslings the incubation period is prolonged to about 10 days and the disease course is chronic. Presently, Derzy’s disease is diagnosed among goslings older then 3-weeks-of-age with low levels of maternal antibodies. The most obvious symptoms are retarded growth and incomplete feathering. During post mortem examination the anatomopathological changes characteristic for Derzsy’s disease are found in the liver and cardiac muscle. The laboratory diagnostics of Derzsy’s disease is mainly focused on clinical and anatomopathological examinations as well as on serologic, virologic, and histopathologic examinations, together with the application of molecular biology methods. The only method of Derzsy’s disease control is vaccination with living vaccine based on goose parvovirus strain and with bivalent inactivated vaccine containing goose parvovirus strain and Muscovy duck parvovirus strain. Laying geese are vaccinated before and during the middle of the laying season, and the immunity persists during whole laying season.