Causes: Avian adenovirus.

Effects: Incubation period is 7-9 days. Loss of colour in pigmented eggs, thin-shelled, soft-shelled or shell-less eggs and a reduction in production up to 40%. Watery albumin and reduction in egg size. Inappetence, dullness and diarrhoea may occur.

Egg drop syndrome is an acute to chronic disease affecting laying birds, ie. laying chickens, ducks and guinea fowl. It is caused by the avian adenovirus, which is 70-75 nm in length. All chickens are susceptible, but brown layers are most susceptible.

It can spread vertically through the embryonated egg, by faecal-oral routes, and by contaminated water.

It occurs worldwide, however, the disease has not been reported in chicks in the US. The virus has been isolated from migratory ducks in the US.

(There is a 7-9 day incubation period)

Signs include loss of colour in pigmented eggs, thin-shelled, soft-shelled or shell-less eggs and a reduction in production up to 40%. Watery albumin and reduction in size of the egg, inappetence, dullness and diarrhoea may occur.

Lesions include inactive ovaries and atrophied oviducts, uterine oedema, exudates in the shell gland, flaccid ovules and a mild splenomegaly (enlarged spleen).

Clinical signs, gross lesions, and inclusion bodies in the epithelial cells of the shell gland are diagnostic.

Isolation and identification of the virus in embryonated duck eggs from a flock free of EDS is the most sensitive test for EDS.

Immunofluorescent staining of fluids with specific conjugated antisera, and the Haemagglutination-inhibition test and ELISA to check for antibody in blood are also helpful.

It simulates IB.

Biosecurity is important. An inactivated vaccine can be given during the pullet-rearing phase to help prevent the disease.

None.