Avian adenovirus II spleenomegaly (AAS) (Haemorrhagic enteritis (HE)-related infections)

Occurrence: Worldwide.
Species affected: Chickens.
Age affected: All ages.
Causes: Adenovirus is a DNA virus with a diameter of 70-90mm.
Effects: Paleness, depression, bloody diarrhoea, asphyxia with mortality up to 60%.

Detailed causes:
ASS is caused by a nonenveloped, DNA Adenovirus with icosohedral symmetry of diameter 70-80 mm. there are three serologically distinct avian adenoviruses, which can be differentiated by the AGP test. Serotype I viruses cause IBHV, quail bronchitis, HE and MSDV. Serotype I produces AAS and serotype III virus produces egg drop syndrome. AAS affects chickens of all ages. AAS is spread laterally by the oral route or vertically through the cloaca.

Clinical signs:
Signs include paleness, depression, mortality (to 60%), bloody diarrhoea, and asphyxia (can’t breathe) in AAS.

Postmortem lesions
Lesions include haemorrhages in the gut, liver, proentriculus and gizzard and anaemia. An enlarged mottled spleen and free blood in the intestines can be seen and with MSD oedema and congestion of lungs are also evident.

Agar gel precipitin (AGP) test and ELISA can be used to measure antibodies to AAS. Intranuclear inclusion bodies occur in the reticuloendothelial (RE) cells of the spleen. It simulates coccidiosis, VVND, bacteria and fungi.

Treatment and control:

Commercial vaccines are available for use at 4 weeks in the water for HE and MSD.