Pathology and Virus Tissue Distribution of Turkey Origin Reoviruses in Experimentally Infected Turkey Poults

Abstract

Abstract. The pathogenesis of 4 isolates of turkey-origin reovirus (NC/SEP-R44/03, NC/98, TX/98, and NC/85) and 1 chicken-origin reovirus (1733) was examined by infecting specific pathogen free (SPF) poults. These turkey-origin reovirus (TRV) isolates were collected from turkey flocks experiencing poult enteritis and are genetically distinct from previously reported avian reoviruses. Microscopic examination of the tissues collected from the TRV-infected poults revealed different degrees of bursal atrophy characterized by lymphoid depletion and increased fibroplasia between the bursal follicles. To understand the relationship between virus spread and replication, and the induction of lesions, immunohistochemical staining (IHC) for viral antigen, in situ hybridization (ISH) for the detection of viral RNA, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for the detection of apoptosis in affected tissues was performed. Both IHC and ISH revealed viral antigen and RNA in the surface epithelial cells of the bursa, in macrophages in the interstitium of the bursa and, to lesser degree, in splenic red pulp macrophages and intestinal epithelial cells. Increased apoptosis of bursal lymphocytes and macrophages was observed at 2 and 5 days postinoculation. No lesions were found in tissues from poults inoculated with the virulent chicken-origin strain, however viral antigen was detected in the bursa and the intestine. Although all TRVs studied displayed similar tissue tropism, there were substantial differences in the severity of the lesions produced. Poults inoculated with NC/SEP-R44/03 or NC/98 had moderate to severe bursal atrophy, whereas poults inoculated with TX/ 98 or NC/85 presented a mild to moderate bursal lymphoid depletion. The lymphoid depletion observed in the bursa appears to be the effect of an indirectly induced apoptosis and would most likely result in immune dysfunction in poults infected with TRV.

The role of avian reoviruses in turkey tenosynovitis/arthritis

“…Three routes of inoculation (oral, intratracheal and footpad) were used. These routes of inoculation have been used in previous studies on reovirus infection in chickens (Islam et al, 1988;Jones et al, 1994) and turkeys (Al- Afaleq & Jones, 1989;Pantin-Jackwood et al, 2007). Although 1-day-old poults in Experiment 1 were positive for reovirus before inoculation, we continued with the experiment because several years of diagnostic PCR testing of faeces have indicated that Minnesota poults are usually positive for reovirus and our intent was to evaluate the effect of TARVs on turkeys raised in Minnesota.…”

The pathogenesis of low pathogenicity H7 avian influenza viruses in chickens, ducks and turkeys

“…Tissue sections were cut (4 μm thick) from paraffin-embedded tissue samples and mounted on charged glass slides (Superfrost/Plus; Fisher Scientific). Deparaffinization, antigen retrieval and blocking procedures have been previously described [24]. A 1:2,000 dilution of a mouse-derived monoclonal antibody (P13C11) specific for a type A influenza virus nucleoprotein (developed at Southeast Poultry Research Laboratory, USDA) was applied and allowed to incubate for 2 hours at 37°C.…”

Determination and analysis of the full-length chicken parvovirus genome

“…Numerous viruses have been detected in or isolated from the intestinal tract of poultry (both diseased and healthy), and have subsequently been implicated in poultry enteric disease. These viruses include the avian reoviruses, rotaviruses, astroviruses and coronaviruses; despite these diagnostic efforts and viral descriptions, the role these viruses play in the enteric syndromes are still poorly understood (Guy, 1998;Pantin-Jackwood et al, 2008a;Pantin-Jackwood et al, 2007a;Pantin-Jackwood et al, 2008b;Pantin-Jackwood et al, 2007b;Reynolds et al, 1987;Spackman et al, 2005).…”