The role of avian reoviruses in turkey tenosynovitis/arthritis

Abstract

Turkey arthritis reovirus (TARV) has been isolated from the gastrocnemius tendons and tibiotarsal joint fluid of lame male turkeys >12 weeks old in the Midwest. Two experiments were conducted to compare the pathogenicity in turkeys of three TARVs (TARV-MN2, TARV-MN4 and TARV-O'Neil), one turkey enteric reovirus (TERV strain MN1) and one chicken arthritis reovirus (CARV strain MN1). Two hundred microlitres of virus were inoculated by the oral, intratracheal, or footpad route into 6-day-old poults placed in isolator units. Poults were necropsied at 1 and 4 weeks post infection in Experiment 1, and at 2 and 4 weeks post infection in Experiment 2. Reovirus was detected by reverse transcription-polymerase chain reaction and virus isolation in tendons of TARVinoculated poults at 1, 2 and 4 weeks post infection. TARV-O'Neil and TARV-MN2 were detected in tendons of sentinal birds at 1 and 4 weeks and 1 week p.i., respectively. In general, TARVs produced lymphocytic tenosynovitis of the gastrocnemius and digital flexor tendon sheaths without inflammation of the tendons proper. In Experiment 1, poults inoculated with TARV-MN2 and TARV-O'Neil had significantly higher gastrocnemius tendon inflammation scores, as determined by histology, than those inoculated with TERV-MN1 or CARV-MN1. In Experiment 2, poults inoculated with TARV-MN2 and TARV-O'Neil had significantly higher gastrocnemius tendon inflammation scores than those inoculated with TARV-MN4 and virus-free medium (negative control group). Koch's postulates was fulfilled when TARV-MN2 and TARV-O'Neil were re-isolated from tendons of poults that had originally been challenged with either of these viruses. Results of these experiments indicate that TARVs have a unique ability to induce gastrocnemius tenosynovitis in turkeys and that administration of TARV-O'Neil through the oral or intratracheal route is a reproducible model to study pathogenesis of TARV infection.

Phylogenetic analysis, genomic diversity and classification of M class gene segments of turkey reoviruses

“…The M2-III genotype contained TARV-MN4, TERV-MN5, an enteric CRV strain (AVS-B) isolated in 2006, and an arthritis CRV strain (916S1) isolated in 1992 from Taiwan further indicating possibility of reassortment between chicken and turkey reoviruses. Experimentally, TARVs and TERVs are able to replicate in chickens and may be able to cause enteritis/diarrhea while CRVs are able to replicate in turkeys without causing any disease (Rosenberger et al, 2013a;Sharafeldin et al, 2014).…”

“…From tendons and/or joint fluids of these cases, we isolated TARVs in QT-35 cells as previously described (Mor et al, 2013b). For histopathology, gastrocnemius and digital flexor tendons were removed and immersed in 10% buffered formalin and processed as previously described (Sharafeldin et al, 2014). Fecal samples from enteritic turkeys were also processed for isolation of TERVs as previously described (Jindal et al, 2010;Mor et al, 2013a).…”

“…After this, subsequent reports of arthritis-associated reoviruses in turkeys were lacking. However, we recently reported on the isolation of reoviruses from tendons of 12-18-week-old market age tom turkeys from the upper Midwest area of the U.S. On experimental inoculation in turkey poults, these viruses caused tenosynovitis and were named turkey arthritis reoviruses (TARVs) to differentiate them from turkey enteric reoviruses (TERVs) isolated from healthy and enteritic poults (Mor et al, 2013b(Mor et al, , 2014bSharafeldin et al, 2014).…”

Altered Biomechanical Properties of Gastrocnemius Tendons of Turkeys Infected with Turkey Arthritis Reovirus

“…We have found that inoculation of 1-week-old turkey poults with TARV induces histologic tenosynovitis at 4 weeks PI without clinical lameness [5]. However, clinical lameness can be seen at 8 weeks PI, which later progresses at 12 and 16 weeks PI [6].…”

“…Such lesions were absent in poults inoculated either with turkey enteric reovirus (TERV) or with chicken arthritis reovirus (CARV) [5]. Oral inoculation of TARV in 1-week-old turkey poults induced clinical signs of lameness at 8 weeks of age, which increased in severity by 12 and 16 weeks of age [6].…”