Characterization, diagnosis and environmental survival of turkey arthritis reoviruses

Abstract

After a hiatus of >20 years, reovirus-associated lameness/arthritis has resurfaced in the U.S. We have isolated several strains of TARV (turkey arthritis reovirus) from such cases showing signs of wing tip bruises and unilateral or bilateral swelling of the tibiotarsal joints. Gastrocnemius or digital flexor tendons were occasionally ruptured. We have characterized these viruses based their complete S, M and L class gene sequences. Based on our results, we have proposed a new genotype constellations (GCs) system for all avian reoviruses (ARVs) including those of turkeys, chickens, ducks, and geese. According to M class genotype, turkey reoviruses formed three types of genotype constellations while seven, three and two GCs were formed by chicken, duck and goose reoviruses, respectively. Point mutations and reassortments were observed in S, M and L genes within TARVs and among TARVs, turkey enteric reovirus (TERVs) and chicken reoviruses. We also developed a TaqMan real time RT-PCR (rRT-PCR) for the detection of turkey reovirues; the detection limit was 10 genome copies per reaction. The survival of three TARVs, one TERV, and one CRV isolate was studied in poultry litter and drinking water. All five viruses survived for 9 to 13 weeks in sterile water and for >10 days in non-sterile water. In autoclaved litter, the viruses survived for 6 to 8 weeks. In non-autoclaved litter, the survival was for 7 to 9 days only. We tested the antiviral efficacy of five commonly used disinfectants (Virocid, Keno X5, Synergize, One Stroke, and Tek Trol) against the five viruses (three TARVs and one each TERV and CRV). At their recommended concentrations, all five disinfectants inactivated more than 4 log10 TCID50 of all viruses within 10 min indicating that commonly used disinfectants can be an effective tool in the control of these viruses.