Infectious bronchitis virus (IBV) and avian reovirus (ARV) cause significant losses in the poultry industry throughout the world. A cross-sectional study was conducted in four villages in Manjacaze district, Southern Mozambique, to determine the seroprevalence of IBV and ARV. A total of 467 serum samples from adult unvaccinated backyard chickens were screened using commercial and competitive enzyme-linked immunoabsorbent assay kits. Our results showed anti-IBV and anti-ARV antibodies in all surveyed households and villages. The overall seroprevalence was 89.5% (95% confidence interval &#91;CI&#93;: 77.2-97.4) and 95.7% (95% CI: 88.0-99.2) for IBV and ARV, respectively. The risk of becoming exposed to IBV was lower in Chidenguele village compared with the other three villages (p > 0.05). However, no statistically significant differences were observed for becoming exposed to ARV between villages (p < 0.05). The backyard chickens tested in this study had no previous history of vaccination, outbreaks or typical clinical signs of IB and AR diseases. Therefore, the presence of antibodies to IBV and ARV was considered clear evidence that the birds have been naturally exposed to those two infectious agents, and the infection was of subclinical type. It is concluded that IBV and ARV are widespread in backyard chickens in the studied area. These obtained data are essential for design and implementation of chicken health development programmes. CONTRIBUTION: The epidemiology of IBV and ARV of backyard chicken in Mozambique is unknown. This study determined the seroprevalence of IBV and ARV in backyard chicken health. The obtained data are essential for design and implementation of chicken health development programmes

Introduction: Avian reovirus (ARV) infections in poultry populations are reported worldwide. The reovirus belongs to the genus Orthoreovirus, family Reoviridae. The aim of the study was to evaluate the incidence of ARV infections in the poultry population based on diagnostic tests performed in 2010–2017. Material and Methods: Samples of the liver and spleen were collected from sick birds suspected of ARV infection and sent for diagnostics. Isolation was performed in 5–7-day-old SPF chicken embryos infected into the yolk sac with homogenates of internal organs of sick birds. Four primer pairs were used to detect the σNS, σC, σA, and µA ARV RNA gene fragments. A nested PCR was used for the detection of the σNS and σC genes. Results: In 2010–2017, ARV infection was found in birds from 81 flocks of broiler chickens and/or layers, 8 flocks of slaughter turkeys, and in 4 hatchery embryos at 17–20 days of incubation. The primers used in RT-PCR and nested PCR did not allow effective detection of ARV RNA in all virus-positive samples. Conclusion: The problem of ARV infections in the poultry population in Poland still persist. The primers used for various ARV segments in RT-PCR and nested PCR did not allow effective detection of RNA in the visceral organs of sick birds. The presented results confirm the necessity of using classical diagnostic methods (isolation in chicken embryos, AGID).

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 groupspecific 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.

Objectives: The present study estimated the seroprevalence of avian reovirus (ARV) infections in backyard chickens of the Mymensingh district in Bangladesh. Materials and Methods: Considering several risk factors, a total of 460 serum samples were col¬lected from backyard chickens from eight Upazilas of the Mymensingh district in Bangladesh. Blood samples were taken from the wing vein using 3-ml sterile syringes and kept at room tem¬perature for clotting in a slanting position and then transported to the laboratory maintaining the cool chain. Subsequently, the prepared sera were harvested and stored at &#8722;20&#xb0;C until used. Finally, an indirect enzyme-linked immunosorbent assay (ELISA) was performed to detect ARV-specific antibodies using a commercial ARV antibody detection ELISA test kit. Results: The results revealed high prevalence rates of ARV antibodies, with a total seroprevalence of 69.78% (321/460). Area-wise, 74.55% (82/110) seroprevalence was recorded as the highest in Mymensingh Sadar, whereas 64% (32/50) was the lowest in Gauripur Upazila. With regard to sex, female chickens showed a significantly higher (p < 0.05) seroprevalence as 90.33% (271/300) compared to male chickens 31.25% (50/160). With regard to age groups, the seroprevalence of ARV infection was 59.33% (89/150) within 28 weeks, 82% (205/250) within 916 weeks, and 45% (27/60) within 1720 weeks, respectively. Based on hygienic conditions, the highest sero¬prevalence of ARV was noted in backyard chickens housed in poor conditions 80% (120/150) than good conditions 50% (40/80). Backyard chickens reared in free-ranging conditions exhibited a significantly higher seroprevalence 73.33% (220/300) of ARV antibodies compared to rearing in separate houses 63.12% (101/160). The seroprevalence of ARV was higher in crossbreeds 71.67% (43/60), brought from market 76% (38/50), and unhealthy 78.57% (55/70) backyard chickens than non-descriptive indigenous 69.5% (278/400), home-reared 69.02% (283/410), and healthy chick¬ens 68.21% (266/390). Conclusion: The high prevalence of ARV antibodies revealed in the current study indicates an extensive exposure of ARV to backyard chickens in Bangladesh that may be transmitted naturally to other chickens, ultimately leading to ominous economic effects on the poultry sector. [J Adv Vet Anim Res 2020; 7(3.000): 546-553]

This review article focuses on avian reovirus (ARV) regarding the virus characters, susceptibility and transmission, the different clinical forms, laboratory diagnosis, and preventive measures.  Despite most of ARV strains are abundant and innocuous, they are responsible for many diseases conditions in poultry industry. The pathogenic ARV strains induce great economic losses including growth retardation, increasing culling rate, high mortality rate, immunosuppression, and increasing the carcass rejection rate at processing. Strains of ARV belong to the family Reoviridae and genus Orthoreovirus are non-enveloped and double-stranded RNA. Almost all of avian species are susceptible to infection especially at young ages. The virus rapidly spreads among flocks via the horizontal, vertical, and mechanical routes. The infection with ARV is mainly associated with arthritis/ tenosynovitis and runting stunting syndrome. However, other clinical pictures such as gastroenteritis, hepatitis, myocarditis, and respiratory disease are also related to ARV infections. Laboratory diagnosis is based on isolation and characterization of the virus using conventional methods of detection. Nevertheless, recent molecular techniques are also regarded as suitable for the efficient diagnosis. Serological detection of specific ARV antibodies have been also applied. Adoption of hygienic measures and vaccination with live or inactivated vaccines are the most suitable methods for the prevention of field ARV infections.