Detection of Avian Reoviruses in Wild Birds in Poland

Abstract

Introduction: The purpose of this study was to determine the occurrence of avian reovirus (ARV) infections in wild birds in Poland and attempt to propagate the selected ARV strains in chicken embryo kidney (CEK) cells or chicken SPF embryos.

Material and methods: The study included 192 wild birds representing 32 species, collected between 2014 and 2016. A part of the S4 segment encoding the σNS protein of avian reoviruses (ARVs) isolated from different species of wild birds from that period was amplified.

Results: The presence of ARV was demonstrated in 58 (30.2%) wild birds belonging to nine orders. The isolated strains were propagated in chicken embryos by yolk sac inoculation, and CPE was induced in the infected CEK monolayer. Agar gel precipitation showed that two ARV isolates from rock pigeon and mute swan shared a common group-specific antigen with chicken reovirus S1133. Specific products of predicted size were found in two ARV isolates from the chicken embryo passage and 13 ARVs isolated from CEK cells.

Conclusion: The study indicates the high prevalence of ARV among wild birds in Poland and its possible transmission to farmed birds.

Keywords: Poland; avian reovirus; wild birds.

Fig. 1

Antigen-specific group of reovirus in agar gel immunodiffusion (AGID) test. PC – positive control S1133 chicken reovirus antigen (Charles River Laboratories, USA), NC – negative control, A – S1133 reovirus antiserum (Charles River Laboratories, USA), 1 – hepatic homogenate from chicken embryos infected with material from rock pigeon, 2 – embryonic fluids and membranes from chicken embryos infected with material from rock pigeon, 3 – hepatic homogenate from chicken embryos infected with material from white stork, 4 – embryonic fluids and membranes from chicken embryos infected with material from white stork

Fig. 2

Changes in chicken embryo kidney (CEK) cell cultures. Pictures taken at 72–120 h p.i. with the 3rd virus passage. A – negative control – non-infected CEK cells, B – CPE in CEK cells infected with reference strain S1133, C – CPE in CEK cells infected with homogenate of the kidney from grey heron, D – CPE in CEK cells infected with homogenate of the intestine from common kestrel, E – CPE in CEK cells infected with homogenate of the intestine from rock pigeon, F-CPE in CEK cells infected with homogenate of the kidney from white stork. 200× (Axio Observer D1, Zeiss, Germany)