<div style="text-align: justify;">The present study was intended to investigate the sensitivity of different tissues of tumorous and non-tumorous birds to the polymerize chain reaction-baseddiagnosis of Marek&rsquo;s disease. Tissue samples were collected from spleen, sciatic nerve, feather follicles and tumour parts (if any)of chickens during the routine necropsy examination. The presence of Marek&rsquo;s disease virus was examined using primers for 132 bp repeats of BamHI-H regionand positive samples were sequenced for 132 bp repeats and Meq gene. In the birds showing tumours, various samples such as the spleen, feather pulp, sciatic nerve and tumour tissue yielded positive results in &nbsp;92.31%, 88.46%, 100% and 100% cases respectively. Amongst non-tumorous birds, 11.53% spleen, 23.07% feather pulp and 11.53% sciatic nerve were found positive. This is the first comparative study between nerve and other organs samples for molecular diagnosis of Marek&rsquo;s disease. Data generated shows that the probability of false negative in tumorous birds and false positive in non-tumorous birds was comparatively low while employing nerve tissue than spleen and feather follicles. Thus, it may be concluded from our study that nerves are a more reliable and robust diagnostic organ in comparison to the other organs used for conventional diagnosis.</div>

Comparative study on biological material for molecular diagnosis of <em>Gallid herpesvirus 2</em>

<div style="text-align:justify">Infectious laryngotracheitis (ILT), caused by <em>Gallid herpesvirus</em>1, is one among the respiratory diseases of poultry gradually spreading worldwide, including Indian subcontinent. Present study was carried out to identify the pathogen from the suspected cases of the disease. The tracheal tissue samples (pooled) were collected from the birds suspected to have died of ILT from 26 commercial poultry farms located in and around Namakkal district of Tamil Nadu state of India. On post-mortem examination, haemorrhagic caseous exudate and fibrinous pseudo-membrane adhered to tracheal mucosa were noticed. A total of 22 farms were found positive through PCRs targeted against <em>ICP4</em> gene and the thymidine kinase (<em>TK</em>) gene followed by confirmation through sequencing. Histopathology examination revealed decilliation, hyperplasia, degeneration and/or loss of tracheal epithelium with severe submucosal edema. There was infiltration with numerous lymphocytes, macrophages and plasma cells in milder infections, whereas presence of fibrinous exudates admixed with numerous erythrocytes and inflammatory cells like heterophils and lymphocytes were seen indicating the severe acute form of the disease. A fibrinous pseudomembrane was seen firmly attached to the inflamed and necrotic mucosa in subacute cases. Further, virus was isolated from randomly selected 5 PCR positive tracheal tissue samples in embryonated chicken eggs through chorioallantoic membrane (CAM) route. The typical pock lesions were observed on CAM along with engorged blood vessels and thickening of the membrane. Present study has reported the disease ILT among poultry flocks in the Namakkal district of Tamil Nadu and raises the concern for thorough investigation of the nature of prevailing pathogen in the region.</div>

Comparative study on biological material for molecular diagnosis of Gallid herpesvirus 2

Infectious Laryngotracheitis in Layer Birds from Tamil Nadu, India