The authors review their diagnostic and experimental experiences obtained in 2003 about diseases caused by parvo-, circo-, reo- and polyomavirus in young geese. During that period they diagnosed the most frequently the typical form and the form mainly with enteric signs and changes of Derzsy disease. Frequency of occurrence of diseases caused by circo-, reo- and polyomavirus increased, compared to previous years. From epidemiological and diagnostic point of view they found those frequent cases significant when Derzsy disease occurred later (at the age of 6-8 weeks) in immunosuppressed goose flocks infected with circovirus. In the organs of infected animals pathological and histopathological changes typical to Derzsy disease and parvovirus were detectable. In goose flocks infected with circovirus co-infections with other pathogens (viruses, bacteria, fungi) were more frequent and the losses caused by them were more severe than in flocks having adequate general resistance. By experimental challenge it was proven that due to a circovirus infection at the age of 2 weeks, at the age of 6 weeks severe lymphocyte depletion, vaculoic degeneration and cytoplasmatic inclusion bodies developed in the lymphoid organs, especially in bursa Fabricii. In the inclusion bodies virus particles of 12-14 nm, organised in paracrystals were detectable by electron microscope. At the age of 7-8 weeks follicle atrophy and fibrosis were observable in the damaged bursa, which explains immuno-suppression state. During experimental challenge of day-old and 3 weeks old geese and mulard ducks with parvovirus strains of different (goose and duck) origin, it was proven that parvovirus of mulard duck origin does not cause disease in goose, but virus strains of both species origin (the strain causing Derzsy disease in goose and strain of duck origin) may cause disease in mulard duck. It was also demonstrated that degenerative and inflammatory changes of the musculatory and nervous system caused by strain of duck origin are in the background of severe motor disorders and paralysis. In the liver and spleen of day-old goslings challenged experimentally with reovirus, inflammatory-necrotic foci were detectable from the 4th day following infection (in connection with viraemia) and motor disorder, lameness and inflammation of the joint and sheaths developed by the 2nd week after the infection. It was frequently found in the practice that in flock infected by polyomavirus deaths occurred continuously during the 6-8 th weeks or after a break of some weeks a newer wave of deaths occurred. In experimentally challenged day-old or 10-day-old animals 7-8 weeks elapsed between serological response and infection, which explains long lasting deaths observed in the practice.
|Number of pages||8|
|Journal||Magyar Allatorvosok Lapja|
|Publication status||Published - Jan 1 2005|
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