A drop in egg production due to EDS in layer flocks is usually associated with the appearance of shell-less eggs. A drop in egg production without shell-less eggs can be due to a variety of causes. These include nutritional, management, environmental and disease factors. Many causes can be identified in the field and specimens should only be submitted to confirm the diagnosis of disease caused by infectious agents.

Diagnosis

Clinical signs, serology.

Specimens required

1. Fresh or frozen sera, collected early during the problem (within 7 days of onset of egg drop), and again during convalescence (3 to 4 weeks later). If the flock is not vaccinated, the range of titres in conjunction with clinical signs would lead to diagnosis, without the need for paired sera.