Fowl Adenovirus Serotype Research Articles

Comparative serological studies with egg drop syndrome virus

The sensitivities of five serological tests (haemagglutination inhibition, ELISA, serum neutralisation, fluorescent antibody and agar gel immunodiffusion) for detection of Egg Drop Syndrome virus antibody were compared. In experimentally inoculated birds seroconversion was first detected at five days post-inoculation using haemagglutination inhibition, ELISA, serum neutralisation and fluorescent antibody test, and at seven days post-inoculation using agar gel immunodiffusion. Sera from birds experimentally infected with two or more different fowl adenovirus serotypes gave positive reactions in some of these tests, as did a small percentage of haemagglutination inhibition negative field sera. It is concluded that only haemagglutination inhibition or serum neutralisation should be used for detection of infection in commercial birds.

An investigation of vertical transmission of a fowl adenovirus serotype 8.

An investigation of vertical transmission of a fowl adenovirus serotype 8.

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.

Development of a microtitre fluorescent antibody test for serological detection of adenovirus infection in birds

The development of a microtitre fluorescent antibody test, for detection of adenovirus antibody is described. Chick embryo liver cells, infected with fowl adenovirus were found to be more suitable for the test than chick kidney, since a proportion of the chick kidney cells were found to contain non-viral cytoplasmic inclusions which were easily confused with specific viral fluorescence at the low power magnifications used in the test. It was demonstrated that a single positive serum would stain cultures infected with 11 different serotypes of fowl adenovirus, and two serotypes of turkey adenovirus with only minor differences in titre, thus confirming the presence of a common antigen in fowl and turkey adenoviruses. In a survey for adenovirus antibody a total of 595 avian sera (453 fowl and 142 turkey) were screened by double immuno-diffusion and microtitre fluorescence. A total of 52.6% of the sera was positive by double immuno-diffusion while 70.8% were positive by microtitre fluorescence.

Adult Coturnix Quail Bronchitis

Quail bronchitis was confirmed by recovery of fowl adenovirus serotype 1 from 2 flocks of adult birds (Coturnix coturnix japonica) that were reared commercially for their eggs in the Republic of Singapore. Both flocks were reported to have a fall in egg numbers of 10-15%. The main clinical signs were respiratory distress and soft-shelled and white eggs lacking shell pigmentation.

Further Studies on the Classification of Fowl Adenoviruses

In addition to the 8 fowl adenovirus serotypes described previously, 3 new serotypes were recognized. Two, A-2 and C2-B, were isolated in the U.S.A., and one, 380, in Northern Ireland. In addition another isolate, X-11, has a broader antigenicity than YR-36 and therefore should be used instead of YR-36 as prototype strain. It is concluded that there are at least 11 distinct fowl adenovirus serotypes on the basis of the serum-neutralization test.

Isolation of viruses from clinical outbreaks of inclusion body hepatitis

Sixteen outbreaks of inclusion body hepatitis (IBH) in fowls were investigated. Most cases occurred in broilers, and birds 4-9 weeks old were affected. Mortality occurred over a period of 3-5 days, and reached 5% in some cases. The main pathological finding was a diffuse and generalised hepatitis, with eosinophilic intranuclear inclusions in the hepatocytes. From these outbreaks 46 adenoviruses and 6 reoviruses were isolated. The adenoviruses were classified into 5 serological types. Two outbreaks of IBH in pigeons were also examined. Herpesviruses and adenoviruses were isolated from both cases. It was possible to assign one adenovirus isolate to a known fowl adenovirus serotype.

Adenovirus-SV40 “hybrids”: Plaque purification into lines in which the determinant for the SV40 tumor antigen is lost or retained

Inclusion body hepatitis (IBH), hydropericardium syndrome, and gizzard erosion associated with fowl adenovirus (FAdV) infections are reported globally and resulted in significant poultry industry economic losses. In 2018, severe IBH appeared in Pakistan in a 17-week-old layer flock. Subsequently, a FAdV-11 strain (designated as PKFAd18) was isolated from liver samples and identified based on phylogenetic analyses of the serotype-specific L1 region of the capsid hexon gene. There is no complete genome sequence of the Pakistani FAdV-11. This study successfully sequenced the complete genome of PKFAd18. The full genome of PKFAd18 contains 43 840 base pairs (bp) with a G + C content of 53.9 %, which is comparable to other FAdV serotypes. Similar to other FAdV-11 strains, PKFAd18 has only one fiber, while FAdV-1 and FAdV-4 have two fibers. Notably, PKFAd18 showed unique characteristics compared to other FAdV-11 strains. A natural large genomic deletion (1215 bp) appeared in tandem repeat region two, relative to the ON-NP2 strain. Phylogenetic analyses of the PKFAd18 penton gene showed higher homology with FAdV-9, highlighting potential natural recombination between FAdV-11 and FAdV-9. Moreover, the pathogenicity of PKFAd18 studied in specific-pathogen-free chickens showed that PKFAd18 is capable of inducing severe IBH and could be responsible for IBH in Pakistan. Thus, the first complete genome of FAdV-11 in Pakistan was sequenced in this study, which enriches the diversity of knowledge about FAdV-11 and is useful for developing diagnostics and vaccines for IBH induced by FAdV-11 in Pakistan.