Detection, isolation and characterization of turkey-origin rotaviruses present in commercial flocks in the United States

Authors: Day, James; Spackman, Erica; Pantin Jackwood, Mary; Zsak, Laszlo

Submitted to: Western Poultry Disease Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/31/2008
Publication Date: 4/9/2008
Citation: Day, J. M., Spackman, E., Pantin-Jackwood, M. J., Zsak, L. 2008. Detection, isolation and characterization of turkey-origin rotaviruses present in commercial flocks in the United States. In: Proceedings of the 57th Western Poultry Disease Conference, April 9-12, 2008, Puerto Vallarta, Mexico. p. 91-92.

Interpretive Summary: Enteric disease consistently results in economic loss for the poultry industry due to poor weight gain and the inability of young chickens and turkeys to utilize their feed properly. Recognized enteric disease syndromes such as Poult Enteritis Complex (PEC), Poult Enteritis Mortality Syndrome (PEMS), and Runting-Stunting Syndrome (RSS) continuously occur in poultry producing areas of the United States. The specific infectious agents (viruses or bacteria) that cause these syndromes are presently unknown, and disease signs such as diarrhea and poor weight gain are difficult to reproduce in controlled laboratory experiments. It is likely that PEC, PEMS, and RSS are each caused by the interaction of multiple viruses and perhaps bacteria acting together to cause disease. The present study was initially undertaken with poultry industry partners in order to continue the surveillance of turkey flocks for the presence of the enteric viruses avian rotavirus, avian reovirus and avian astrovirus. This study focused on flocks in the Midwest United States and revealed the almost ubiquitous presence of astrovirus as well as common occurrences of rotavirus and reovirus. This study also included a number of field samples intentionally collected from otherwise healthy turkeys flocks; enteric viruses were also common in these healthy flocks. Finally, since little recent work has been performed on the avian rotaviruses, particularly those of turkey origin, a straightforward laboratory cell culture technique was utilized to isolate turkey-origin rotaviruses directly from field samples. These isolated viruses will prove very useful as we begin to understand the role the avian rotaviruses play in enteric disease and in poultry performance in general.

Technical Abstract: Poultry enteric syndromes such as poult enteritis complex (PEC) are widespread in the United States. Analysis of intestinal contents from flocks showing signs of enteric disease often reveals infections with numerous suspect viruses. The complex nature of these infections makes laboratory diagnosis and field management of affected flocks difficult. Recently, turkey intestinal samples received from different regions of the United States have tested positive via RT-PCR for avian rotavirus, avian astroviruses and avian reovirus. Certain avian astrovirus types are ubiquitous in commercial turkeys, and the turkey-origin reoviruses do not appear to be a major factor in syndromes such as PEC. This study presents a phylogenetic analysis of rotaviruses detected in commercial turkey flocks, and relates these findings to descriptions of enteric signs submitted from the field. The isolation of turkey origin rotaviruses from field samples is ongoing, and should prove useful in determining their role in poultry enteric syndromes.