Periodic Monitoring of Commercial Turkeys for Enteric Viruses Indicates Continuous Presence of Astrovirus and Rotavirus on the Farms

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 resampled at 2, 4, 6, 8, 10, and 12 wk of age. The samples were screened for astrovirus, rotavirus, reovirus, and turkey coronavirus (TCoV) by a reverse transcriptase and polymerase chain reaction (RT-PCR), and for groups 1 and 2 adenovirus by PCR. Rotavirus was the only virus detected prior to placement (7 of 16 samples examined). All of the commercial flocks were positive for rotavirus and astrovirus from 2 until 6 wk of age, and most were intermittently positive until 12 wk of age, when the birds were processed. Of the 96 samples collected from birds on the farms, 89.5% were positive for astrovirus, and 67.7% were positive for rotavirus. All flocks were negative for TCoV, reovirus, and group 1 adenovirus at all time points, and positive for group 2 adenovirus (hemorrhagic enteritis virus) at 6 wk of age. All the flocks monitored were considered healthy or normal by field personnel. Turkeys placed on research facilities that had been empty for months and thoroughly cleaned had higher body weights and lower feed conversion rates at 5 wk of age when compared to turkeys placed on commercial farms. Intestinal samples collected at 1, 2, and 3 wk of age from these turkeys were free of enteric viruses. This report demonstrates that astroviruses and rotaviruses may be present within a turkey flock through the life of the flock. Comparison of infected birds with one group of turkeys that were negative for enteric viruses by the methods used here suggests that astrovirus and/or rotavirus may affect production. The full impact on flock performance needs to be further determined.

Epidemiological aspects of astrovirus and coronavirus in poults in the South Eastern Region of Brazil

“…In order to verify the Rotavirus and Reovirus presence, the samples were used to infect MA and Vero cells, at three times consecutively, which are not able to support TCoV neither TAstV-2 replication. However, to confirm the absence of these two viruses, pool of all positive samples were submitted to PAGE (polyacrilamide gel electrophoresis analysis) (25). …”

“…In this way, molecular approaches seems to be more appropriated to direct detect viral RNA from clinical samples, by the use conventional and/or alternative reverse transcriptase polymerase chain reaction - RT-PCR (1,5,8,14,18,24,25,29). Since both viruses have been associated to PEMS outbreak in North America (1,2,13,18,22,23,24,27,29) and recently UK and Wales (9), few works describe TCoV and TAstV-2 epidemiology among Brazilian’s producers.…”

Detection and molecular characterization of Porcine astrovirus strains associated with swine diarrhea

“…1,4,5,11,18 The family Astroviridae consists of 2 genera, Avastrovirus and Mamastrovirus, based on the host range of avian and mammalian species, respectively. Astroviruses are small, nonenveloped viruses containing a single-stranded, positive-sense RNA of 6.4-7.3 kb in size.…”

Molecular characterization of avian rotaviruses circulating in Italian poultry flocks

“…Rotaviruses, often detected in combination with several other pathogens (viruses, bacteria and parasites), have been associated with intestinal disease in commercial poultry, although their exact role in the pathogenesis of disease has not yet been completely defined (Reynolds et al, 1987;Mc Nulty, 2003;Day et al, 2007;Pantin-Jackwood et al, 2007;Reynolds & SchultzCherry, 2008). As yet, AvRVs have not been investigated as thoroughly as mammalian rotaviruses, despite their wide distribution among several avian species and the economic impact due to rotavirus associated enteritis in poultry flocks.…”