Application of polymerase chain reaction and fluorescent antibody technique for the diagnosis of inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) caused by fowl adenovirus serotype-4 Rahul S., Kataria J.M., Kumar N. Senthil, Dhama K., Dash B.B., Uma R., Praveen B.N. Division of Avian Diseases, Indian Veterinary Research Institute, Izatnagar - 243122 (U.P.) Abstract The suitability of polymerase chain reaction (PCR) and fluorescent antibody technique (FAT) for the detection of fowl adenovirus serotype 4 (FAV-4) in various tissues viz. liver, spleen, bursa of Fabricius, thymus and kidneys, from cases of experimentally induced inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) in specific pathogen free (SPF) layer chicks was evaluated. Briefly, fifteen (15) SPF chicks at 14 days of age were inoculated orally with an Indian strain of FAV-4 at the dose rate of 104.5 EID50 per chick. Another fifteen chicks served as uninfected control. Both the groups were observed for the development of clinical symptoms and lesions at different intervals up to 28 days post infection. Mortality rate of 13.33 per cent was recorded in infected chicks with characteristic signs and lesions of IBH-HPS viz. typical hydropericardium with accumulation of clear watery straw-coloured fluid in the pericardium, swollen, discoloured and friable livers and congested kidneys. On histopathological examinations basophilic intra-nuclear inclusions were observed in hepatocytes. Various tissues viz. liver, spleen, bursa, thymus and kidneys, were collected from chicks showing characteristic lesions and uninfected controls. Detection of FAV-4 DNA and antigen in these tissues was attempted by PCR and FAT, respectively. Cryosections of the tissues when stained with anti FAV-4 FITC conjugate at optimized working dilution of 1: 20 gave distinct specific fluorescence in all the samples examined. DNA extracted from the different tissues, on testing by PCR for the presence of specific viral DNA gave an FAV-4 specific amplified product of 728 bp size. The tissues from control chicks were found negative for FAV-4 DNA and antigen. Both PCR and FAT detected the presence of FAV-4 in tissues. This confirmed the establishment of experimental infection in chicks, thus proving their utility as tests for the rapid and confirmatory diagnosis of FAV-4 infection in poultry. Top |