Clinical Signs, Morbidity And Mortality Rates Of Ibd
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2.12. Diagnosis of IBDV
2.12.1. Field diagnosis:
188.8.131.52. Clinical signs, morbidity and mortality rates of "IBD" infection:
The incubation period of IBD varies from 2 to 4 days and the infected chicks characterized by acute onset of depression, disinclined to move and peck at their vents (Cosgrove., 1962).
The feed intake is depressed while water consumption may be elevated at IBD infection. And at the end of the course of the disease, birds may show sternal or later at recumbency with coarse tremor (Hitchner., 1963).
The short duration of the chemical signs, morbidity and morbidity rates are considered a diagnostic for IBD, therefore, the affected flocks show depression for 5-7 days during which mortality rises rapidly for the first two days then declines sharply as clinical normally returns(Parkhurst., 1964).
The pericoloacal feathers are stained with urates (Landgraf et al., 1967).
The variety of field infections especially of the respiratory system may follow immunosppression caused by IBD (Faragher et al., 1974).
Clinical IBD has been described in 15 weeks old leghorn strain pullets which showed high morbidity and moderate mortality(Ley et al., 1979).
The variants of IBD type I identified from the Delmarva Peninsula do not produce any characteristic clinical changes during the 7 days period following exposure (Rosenberger and Cloud., 1986).
Very virulent IBDV strains have been isolated in the late 1980 's that became a problem in Europe, several of these isolates