ABSTRACT This study aimed at proposing a new technical criteria for condemnation of turkey carcasses due to fowlpox in turkeys as a contribution for the work of the Brazilian Federal Meat Inspection Service. Skin samples from 30 carcasses of a flock of 840 turkeys (Meleagris gallopavo), previously vaccinated for fowlpox and slaughtered in June 2013, were collected. Samples were submitted to histological examination under light microscopy. The virus was identified using standard PCR techniques. The main histological findings were hyperplasia and hydropic degeneration of the epithelium and the presence of intracytoplasmic eosinophilic inclusion bodies. PCR results yielded 83.3% positive and 16.7% negative samples. Fowlpox virus is species specific, and there are no reports of its occurrence in mammals. The macroscopic and microscopic findings of the skin lesions do not justify the total condemnation of carcasses of poultry affected with fowlpox, except in cases of cachexia or repulsive appearance, as established by SIF regulation.

Seventy-eight chickens from a very high poultry density (approximately eight million) region and twelve backyard chickens from neighboring areas were analyzed by histopathology and additional techniques for the presence of the infectious laryngotracheitis virus. The virus distribution was determined in different tissues using immunohistochemistry (IHC) and polymerase chain reaction (PCR). The disease was histopathologically diagnosed in 41.0% (32/78) of the commercial layers. Lesions were mainly characterized by syncytial cells with eosinophilic intranuclear inclusion body formed from the hyperplastic epithelium of the upper respiratory tract, primary and secondary bronchi, and conjunctiva. IHC showed 70% (21/30) positive signal in the larynx/trachea and, 53.8% (14/26) in the lungs, either in epithelial cells or syncytia. In the turbinates and paranasal sinuses, 29.6% (8/27) of samples showed positive signal. PCR detected the following gallid herpesvirus 1-positive percentages: conjunctiva 63.2% (31/49), lungs 57.6% (30/52), turbinates and paranasal sinuses 56% (28/50), and larynx/trachea 50% (39/78). IHC showed to be a useful additional tool for definitive ILT diagnosis, especially during the subacute phase of the disease when syncytial cells with intranuclear inclusion bodies are no longer observed. PCR using specific primers from ICP4 gene, generating a product of 237 base pairs, was sensitive for ILT diagnosis, and very useful for rapid detection of GaHV-1 in chickens. Fixed tissues allowing histopatological examination and detection of GaHV-1 by PCR, are a good option in areas where farms are located several hundred kilometers away from a diagnostic center, reducing problems with conservation of fresh samples and the risk of virus spread.