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Positive Follow-Up Study on Infectious Bronchitis

by 5m Editor
17 September 2008, at 6:41am

US - The Quigley Corporation has announced successful results from a follow up study conducted by its wholly owned subsidiary, Quigley Pharma, with its veterinary anti-viral compound QR448(a).

The study was designed to determine the duration of anti-viral effect of QR448(a) against infectious bronchitis virus (IBV) in commercial broiler chickens.

The data from the study indicate that day-old commercial broilers, when treated with QR448(a) were protected 50-100% of the time from the weakening clinical pathogenic effects of IBV for up to 4 days compared to 0-20% of the time in untreated birds. The reduction or absence of clinical signs observed, likely indicates little or no damage to upper respiratory tract tissue which is extremely significant because damage to this area caused by untreated IBV infections leaves birds exposed to potentially deadly secondary infections, such as those caused by Escherichia coli, which can be responsible for significant financial losses to poultry producers. Clinical pathogenic signs are defined as watery eyes, mucus in nares and tracheal rales.

Losses are calculated as a result of lower weight gains and feed efficiency in broilers, condemnation of poultry products at processing plants, lowered production and quality of eggs in layers and breeders, mortality, clean-up costs and disruption to operations.

As previously announced, the Company sought and gained advice from commercial market and research leaders from within the poultry industry to establish a development program built on previous positive data and future performance criteria that will best verify the commercial viability and optimize the potential prospects for joint development of the QR448(a) candidate.

Based upon the positive results of this study and the expressed increasing need for additional products to combat IBV by poultry industry leaders, the Company expects to further investigate the effectiveness of the compound.

Dr Richard Rosenbloom, Executive Vice-President and Chief Operating Officer of Quigley Pharma stated, "We are encouraged by the consistency of these data in addition to past results which clearly indicate that the compound effectively reduces the clinical signs and presence of IBV in SPF (egg layer type) as well as commercial broiler (meat-type) chickens. Additionally promising is the 4-day duration of protection and possibility of once per 4-day dose, which could prevent the birds from succumbing to more significant infections."

Professor Mark Jackwood of the Department of Population Health, College of Veterinary Medicine, University of Georgia, USA said, "In the hundreds of times we have challenged chickens with IBV and then treated them with the QR448(a) compound, the reduction of clinical signs in the treated birds has been truly dramatic. It is also important to remember that the amount of live virus in the treated birds could be much lower since our test detects both live and dead viruses. Also, an additional benefit of these viruses in the trachea could be to induce a natural immune response, adding another level of protection against the disease beyond the effective duration of the compound."

About the Study:

The study was conducted by Dr Jackwood who summarised his report as follows:

  • One day old commercial broilers in groups of 10 birds were spray-treated with 1ml of a 1:20 dilution of QR448(a) per bird then challenged with 1 X 104 EID (for 50%) of pathogenic IBV (Mass type) at 2 hrs, 4 hrs, 6 hrs, 1 day, 2 days, 4 days and 7 days post-QR448(a) treatment. Non-treated control birds were also challenged at the same time periods.
  • Birds challenged with IBV and treated with QR448(a) within 4 days exhibited a 50-100% degree of protection from clinical signs of infection. This is in contrast to birds that were challenged and not treated with QR448(a) where the protection based on clinical signs ranged from 0-20%.
  • Tracheal swabbing detected challenge virus in all of the challenged birds not treated with QR448(a). Lower levels of virus (but not statistically significant) were detected in the birds treated with QR448(a), indicating that there was no protection from infection although the reduction or absence of clinical signs in the QR448(a) treated groups likely indicates little or no damage to the upper respiratory tract.
  • Challenge virus detection with mild or no clinical signs in the QR448(a)-treated birds is similar to results from previous studies with QR448(a) although in this study, we did not see a significant drop in the amount of virus in the trachea.
  • Serological and histological data is pending but is not expected to negatively impact these results.
  • In summary, QR448(a) protected broiler chickens for up to 4 days post-treatment from clinical signs of the disease (but not from infection) following challenge with pathogenic IBV.

Subsequent to the positive results of this trial, the Company began an investigation of the effects of the QR448(a) candidate on the transmission of virus in a larger population of broilers in housing conditions more representative of commercial breeding.

5m Editor