Adding yeast extract to culture medium enhances replication of the avian coronavirus infectious bronchitis virus in chicken embryo kidney cells.

Infectious bronchitis virus (IBV), an avian coronavirus, can be isolated and cultured in tracheal organ cultures (TOCs), embryonated eggs and cell cultures, the first two of which are commonly used for viral isolation. Previous studies have suggested that foetal bovine serum (FBS) can inhibit coronavirus replication in cell cultures. In this study, the replication of IBV in chicken embryo kidney (CEK) cell cultures and the Leghorn hepatocellular carcinoma (LMH) cell line was assessed using two different cell culture media containing FBS or yeast extract (YE) and two different IBV strains.

Characterisation of the tracheal transcriptional response of chickens to chronic infection with Mycoplasma synoviae.

Mycoplasma synoviae causes infectious synovitis and respiratory tract infections in chickens and is responsible for significant economic losses in the poultry industry. Effective attachment and colonisation of the trachea is critical for the persistence of the organism and progression of the disease it causes. The respiratory tract infection is usually sub-clinical, but concurrent infection with infectious bronchitis virus (IBV) is known to enhance the pathogenicity of M.

Evaluation of the safety and efficacy of the novel Mycoplasma gallisepticum vaccine, Vaxsafe MG304, after spray-vaccination of 1-day-old specific pathogen-free chicks.

Mycoplasma gallisepticum causes chronic respiratory disease in poultry. A novel vaccine, Vaxsafe MG304 (the ts-304 strain), has greater protective efficacy in chickens than the Vaxsafe MG (strain ts-11) vaccine when delivered by eye drop at 3 weeks of age. Applying this vaccine in the hatchery to 1-day-old birds, using mass administration methods, would improve animal welfare and reduce labour costs associated with handling individual birds.

Pasteurella multocida ST20 is widespread in Australian poultry farms and may infect wild waterbirds.

The bacterial agent that causes fowl cholera, Pasteurella multocida, was isolated from two deceased wild waterbirds in Victoria, Australia, in 2013. Whole genome sequence analysis placed the isolates into ST20, a subtype described in farmed chickens from Queensland, Australia and more recently in feedlot cattle and in pigs across a broader area of the continent. This study also found ST20 between 2009 and 2022 on three chicken farms and two turkey farms located in four Australian states.

Th-1 cytotoxic cell-mediated response predominates in the tracheal mucosa following Mycoplasma synoviae infection of MS-H-vaccinated chickens.

Mycoplasma synoviae is a pathogen of poultry that causes upper respiratory tract disease. MS-H is a live attenuated temperature-sensitive vaccine that effectively control M. synoviae infection in chickens.