Periodic monitoring of commercial turkeys for enteric viruses indicates continuous presence of astrovirus and rotavirus on the farms

Authors: Pantin Jackwood, Mary; Spackman, Erica; Day, James; RIVES, DAVID - PRESTAGE FARMS

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2007
Publication Date: 9/21/2007
Citation: Pantin Jackwood, M.J., Spackman, E., Day, J.M., Rives, D. 2007. Periodic monitoring of commercial turkeys for enteric viruses indicates continuous presence of astrovirus and rotavirus on the farms. Avian Diseases. 51:674-680.

Interpretive Summary: Viral enteric diseases cause substantial economic loss to the US turkey industry; however, how common are enteric viruses in turkey farms is unknown. A survey to detect enteric viruses in intestinal contents collected from turkeys in eight commercial operations and one research facility was performed using molecular detection methods. Intestinal contents were collected from turkeys prior to placement with each flock, being re-sampled at 2, 4, 6, 8, 10, and 12 weeks of age. The samples were examined for the following enteric viruses: astrovirus, rotavirus, reovirus, coronavirus and adenovirus. Rotavirus was the only virus detected prior to placing the turkeys on the farms (7 of 16 samples examined). All of the farms at all other time points were positive for rotavirus and astrovirus. Of the 96 total samples examined throughout, 89.5% were positive for astrovirus and 67.7% were positive for rotavirus. All flocks were negative for coronavirus and reovirus at all time points and positive for adenovirus Type II (Hemorrhagic Enteritis virus) at 6 weeks. All the flocks monitored were considered healthy or normal by field personnel. However, turkeys placed on experimental facilities that had been empty for months and thoroughly cleaned, were heavier at 12 weeks of age when compared to turkeys placed on the commercial farms, and intestinal samples collected from these turkeys were free of enteric viruses. In conclusion, astroviruses and rotaviruses are very common in commercial turkey operations, although the full impact on performance of the flocks is unknown.

Technical Abstract: A longitudinal survey to detect enteric viruses in intestinal contents collected from turkeys in eight commercial operations and one research facility was performed using molecular detection methods. Intestinal contents were collected from turkeys prior to placement with each flock being re-sampled at 2, 4, 6, 8, 10, and 12 weeks of age. The samples were screened for astrovirus, rotavirus, reovirus, and coronavirus by RT-PCR, and for Type II adenovirus by PCR. Rotavirus was the only virus detected prior to placement (7 of 16 samples examined). All of the farms at all other time points were positive for rotavirus and astrovirus. Of the 96 total samples examined throughout, 89.5% were positive for astrovirus and 67.7% were positive for rotavirus. All flocks were negative for coronavirus and reovirus at all time points and positive for adenovirus Type II (Hemorrhagic Enteritis virus) at 6 weeks. All the flocks monitored were considered healthy or normal by field personnel. However, turkeys placed on experimental facilities that had been empty for months and thoroughly cleaned, had significantly higher weights at 12 weeks of age when compared to turkeys placed on the commercial farms, and intestinal samples collected from these turkeys were free of enteric viruses. In conclusion, astroviruses and rotaviruses are very common in commercial turkey operations, although the full impact on performance of the flocks is unknown.