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DuPont Animal Health Solutions provides world leading biosecurity products and solutions developed specifically for disease prevention and control in livestock production facilities.

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DAHS Technical News Bulletin, 01 February 2008

Unique USDA Study Highlights VirkonĀ® S on-farm Efficacy Against Viruses

Leading researchers at the United States Department of Agriculture (USDA) Centres for Epidemiology and Animal Health have confirmed the excellent on-farm efficacy of DuPont™ Virkon® S in eradicating exotic Newcastle Disease (END) virus in a recent Journal of Veterinary Diagnostic Investigationspaper.

The study, headed-up by Brian McCluskey, was devised to cover over 50 infected non-commercial poultry farms after the disastrous South Californian END virus outbreaks of 2002-3. In this broad reaching field research, the authors showed that Virkon® S was 100% effective in eradicating END virus and they concluded that the need for costly sentinel bird placement was eliminated.1 Uniquely, the use of the sentinel birds has validated the excellent on-farm activity of Virkon® S against viruses. Compared with easily detected bacterial infections, such viral challenges have to be demonstrated through live animal models and this assessment was the first of its kind.

The use of sentinel chickens in establishing the negative status of commercial poultry flocks depopulated due to exotic Newcastle Disease virus has in the past been considered to be an economically beneficial process. However, the costs and benefits of using sentinel chickens in non-commercial operations were in question. The objective of the study was to use the sentinel chickens to evaluate whether adequate cleaning and disinfection coupled with an appropriate time period without susceptible poultry species on the premises would eliminate END virus and preclude the need for sentinel chickens before declaring the operation disease free.

The USDA Taskforce used post-infection biosecurity procedures on the 53 non-commercial farms after the END virus outbreaks. The farms had been classified as either ‘infected’ or ‘dangerous contacts’ and after completion of the biosecurity measures, owners had waited 90 days before re-populating their farms.

Prior to the sentinel birds’ arrival on the farms, all feeders and waterers were cleaned and disinfected with 1% Virkon® S and clean shavings put down for bedding. In all, 546 sentinel birds were placed, a mean of 10.1 birds per farm. The birds were all clearly identified by wing tags and owners were requested to move the sentinel birds around to ensure that they were in contact with all other poultry on the farm.

The USDA team concluded that a combination of time and the application of appropriate biosecurity measures with 1% Virkon® S were effective at clearing virus in the 53 non-commercial operations.

The conclusions were based on extensive microbiological testing of the sentinel birds which were all confirmed as negative for END by extensive PCR techniques.

Commenting Mark Blackwell MRCVS, DuPont Animal Health Solutions explains, “This unique field study endorses the excellent efficacy of Virkon® S in the control of END virus. This was a “real world, real farm” eradication problem – not a theoretical laboratory-based study. END is a relatively stable virus and therefore difficult to bring under control especially in the presence of an organic challenge. We are delighted that the authors concluded that the application of appropriate cleaning and disinfection procedures using 1% Virkon® S combined with sufficient time delays, prior to re-population, provides a highly efficient means of bringing potentially devastating END infections under control.”