Goose parvovirus infection occurs worldwide in all those countries where geese are kept in high numbers. The resistance of the virus is very high, it remains alive for months in the sorrounding. Only geese and Muscovy ducks are susceptible. The infection can by acquired via the eggs or in the hatchery especially if eggs of different origin are hatched together or during transport or later particularly if principles of large scale poultry keeping (all in-all out, cleaning, disinfection, isolated keeping of different age groups etc.) have not been observed. Derzsy's disease in clinical form usually appears in goslings between one to four weeks of age. The mortality rate may reach 30 to 60 per cent. In prevention of the disease, apart from good hygiene in the hatchery, proper keeping and feeding of geese flocks, vaccines and hyperimmune sera are also used. Attenuated vaccines are safe they do not cause any adverse effect neither in geese embryos nor in one day old goslings. Clinical appearance of the disease can be prevented by vaccination of the breeder flocks at an age of four weeks old and with administration of two further doses of vaccines immediately before beginning of the egg laying period. Maternal immunity, provided that at least 1 to 50 virus neutralising titre can be measured in the blood sera of one day old goslings, usually protect goslings but maternal antibodies often decline rapidly from the middle fo the egg laying period and in these cases hyperimmune serum (2 ml/goose with a titre of 1 in 800 or more) have to be administered on the day of hatching still before infection. As the goose parvovirus infection is very widespread, not the presence of the infection is important but the immunity of the one day old goslings. Liability of the owner of the breeder flocks or the owner of the hatchery for losses due to Derzsy's disease from an age of one to four weeks of age can be established only if breeder flocks have not been immunised properly or if despite immunisation titre of antibodies against goose parvovirus in the blood sera of one day old goslings were less than 1 in 50, no serum was administered and the purchaser did everything what can be expected in order to avoid infection and losses. Hyperimmune sera brought into circulation should have a titre of 1 in 800 at least. Based on practical experiences even a titre of 1 in 50 does not mean an absolute protection as after challenge losses ranging from 4.2 to 7.7 per cent may occur. But these losses and those occurring after an age of four weeks are the natural risks of goose keeping which can be prevented by proper hygiene and by immunisation of goslings at an age of four weeks. The immunisation of the breeder flocks, traceing the antibody level of the one day old goslings and serum treatment if necessary are the tasks of the egg producer. The hatchery has to prove the origin and proper identification of the breeder eggs and goslings and the observation of the hygienic rules in the hatchery. It is advisable to convince the purchaser to buy only goslings hatched from eggs of known origin and if Derzsy's disease has appeared to let succumbed goslings examined in diagnostic institutes.
|Translated title of the contribution||Remarks for forensic veterinary medical judgement of Derzsy's disease|
|Number of pages||5|
|Journal||Magyar Allatorvosok Lapja|
|Publication status||Published - Dec 1 1997|
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