Gumboro disease in poultry is caused by the Gumboro virus. The highly virulent Gumboroveld strain has been present in the Netherlands since 1986. At the end of 2022 and early 2023, the occurrence of a recent Gumborostam was investigated in visibly healthy flocks, flocks with disappointing technical results and in flocks with visible problems. The research should provide a better picture of the prevalence of Gumboro disease and the role the virus plays in causing other problems. This prevalence study is currently ongoing.
The Gumborro disease strains found as of 2017 differ from the older strains. The recent strains also seem to dominate. The changed strains have been detected on dozens of farms with broilers and rearing laying hens since 2017. The affected companies are scattered all over the country. The flocks in which the altered strains were found showed varying images. The most common complaints were lingering increased mortality, wet stables, reduced growth and disappointing technical results.
The pathogenic potential of the virus for the chick was investigated in 2019. The virus did not cause any mortality in laying hens and broilers, but it did cause long-term and severe damage to the bursa. In 2020, practical research will determine the ability of the old field strain and the recent field strain to break through the maternal immunity generated using vaccinations. Both the classic Gumborostam and the recent Gumborostam were able to lead to an infection in all groups in this experiment. This was evidenced by the severe damage to the bursa and a PCR study showing Gumborovirus. As a result, the field virus is able to lead to an infection before a live vaccine is effective in the chicken.
The question about Gumboro from practice is whether the recent field strain is clinically relevant. The classic clinical picture and the typical peak in failure with muscle bleeding and swollen bursas are rarely observed anymore. However, it is unclear whether an infection from 2 weeks of age leads to a deterioration of the immune system. A possible effect of the recent field strain could be a reduced response to vaccinations or more problems from other pathogens. That is why a new prevalence study is now underway.
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2023-08-08 19:10:50
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