Avian adenovirus alone or followed by infectious bronchitis virus in laying hens

Necrotizing Salpingitis by Fowl Adenovirus in a Backyard Hen

A 3-yr-old Ameraucana hen was received for postmortem examination following a 1-day history of lethargy and death. Gross lesions observed during necropsy were limited to pulmonary congestion and a small clump of egg yolk material in the oviductal lumen. On histopathology, there was a necrotizing salpingitis of the infundibular and isthmus mucosa with amphophilic, intranuclear inclusion bodies in superficial epithelial cells. Transmission electron microscopy identified the intranuclear inclusions as aggregates of adenovirus virions. Fowl adenovirus (FAdV) type A was identified with PCR and sequencing. Although the cause of death was not determined in this case, this is the first report of FAdV type A-associated salpingitis in a hen.

Avian adenoviruses--a review

The literature on avian adenoviruses is reviewed with particular reference to the virion, number of serotypes, epidemiology, diagnosis and association with disease. Using the serum neutralisation test there are probably at least 12 serotypes which share a common avian group antigen distinct from the mammalian group antigen. The three disease complexes most often associated with avian adenovirus infections are respiratory disease, falls in egg production and hepatitis.

Studies on a depressed egg production syndrome in Northern Ireland

A syndrome causing depressed egg production is described. It is characterised either by a failure to attain predicted production targets or by a fall in egg numbers. The depression in production can reach 30% and it may or may not return to normal. For a short period the eggs produced are smaller, lose colour, have poor egg shell strength and many soft shelled eggs are laid. The birds remain apparently healthy and there is a marked age incidence, with most flocks starting this depression in egg production at 29-31 weeks of age. This syndrome has been recently recorded in the Netherlands, but has not been seen before in Northern Ireland. Viruses which agglutinated fowl erythrocytes to very high titres were isolated in chick embryo liver cells from six affected flocks. Three of these isolates were from the oviduct, two from the upper respiratory tract and one from the faeces. These agents are similar to adenoviruses, but were not neutralised by antisera to 11 prototype fowl adenoviruses. In addition, 17 adenoviruses were also isolated from the flocks showing the syndrome described. These isolates fell into five serological types, in addition to nine which could not be typed using antisera to 11 prototype adenoviruses. Investigations of flocks with falls in egg production not conforming to this syndrome yielded five isolates. Six adenoviruses were also isolated from birds with diarrhoea.

Humoral immune response of chicks to different clinical isolates of avian adenovirus type-1

The humoral immune response of 7-day-old chicks to different strains of avian adenovirus (AAV) type-1 was determined by counter immunoelectrophoresis (CIE) and enzyme-linked immunosorbent assay (ELISA). In CIE antibody was detected 14 days post-infection (PI) whereas in ELISA antibody was detected 7 days PI. The ELISA titre reached its peak at 21 days PI in all groups. The pattern of immune response among the groups was found to be similar.

The use of an enzyme-linked immunosorbent assay to detect IgG antibodies to serotype-specific and group-specific antigens of fowl adenovirus serotypes 2, 3 and 4

A sensitive enzyme-linked immunosorbent assay (ELISA) has been developed which can detect serotype and group-specific antibodies (IgG) to fowl adenovirus serotypes 2, 3 and 4. The chickens produced principally type-specific antibodies after a single oral inoculation of virus which enabled that strain to be identified by the ELISA. However, inoculation of an heterologous serotype, although inducing strain-specific antibodies to itself, also induced high levels of antibody to the group-specific antigens. This masked the serotype-specific antibodies in the ELISA to the first serotype. The ELISA, which has similar sensitivity to the serum neutralisation test, could be used as a rapid, easily performed test to identify fowl adenovirus-specific antibodies.

Avian adenoviruses isolated from poultry in Queensland

Adenoviruses isolated from Queensland poultry flocks with respiratory disease and/or egg production problems have been serotyped by comparison with Japanese and Irish types. Two serological types were recognized among 14 isolates examined; 4 were type 112 (Celo type) and the remaining 10 type 506. Isolates B1363 and B4015 were further characterized by immunodiffusion. Both isolates were shown to contain the avian adenovirus group antigen and B1363 also shared a second (type) antigen with Celo (Phelps) strain. Immuno-electron microscopy revealed the presence of adenovirus group antigen and freedom from contamination with other viruses.