Investigation into the aetiology of runting and stunting syndrome in chickens

Abstract

Currently, the aetiology of runting and stunting syndrome (RSS) in chickens is unknown. The impact of RSS on weight gain and microscopic lesions in immunological organs and the duodenum, was investigated in 1-day-old commercial broilers at 12 days following exposure to RSS-contaminated litter. Furthermore, the presence of the viral nucleic acids of three astroviruses and one parvovirus was analysed by in situ hybridization from days 1 through 5 post exposure. A 70% decrease in weight was observed in the RSS-exposed group at the end of the experiments when compared with the unexposed controls. Lesions in the bursa of Fabricius and thymus were present in both groups but were significantly higher at the end of the study in the RSS-exposed group. In contrast, no significant difference in Harderian gland lesions was observed between the groups. Histological lesions in the duodenum were already present 24 h after exposure in the RSS-exposed group only, peaked at day 4 and declined until the end of the study. Results of the in situ hybridization studies clearly indicate replication of three astroviruses (chicken astrovirus, avian nephritis virus [ANV]-1, ANV-2) in the duodenum but not in other organs evaluated. Chicken astrovirus nucleic acids were detected on days 1 and 2 post exposure, while ANV-1 and ANV-2 nucleic acids were observed on several days during the period investigated. Surprisingly, no viral nucleic acid specific for the chicken parvovirus was observed. The results indicate that astroviruses probably play an important role during RSS due to the concurrence of viral RNA detection and lesions in the duodenum.

Detection and molecular characterization of enteric viruses in enteritis-affected commercial broiler chickens in India

“…Our observations of varying levels of nt and aa identities of ANV compared with previously published polymerase gene sequences of ANV from abroad are consistent with the earlier reports (Canelli et al, 2012;Kang et al, 2012). Phylogenetic analysis revealed that all ANVs of this study clustered together.…”

“…De Wit et al (2011) inoculated 3-week-old SPF layer chickens with an ANV (isolate 19), which resulted in diarrhoea and severe depression and mortality and pathological changes in kidneys and lymphoid organs. Kang et al (2012) exposed 1 day old commercial broilers to litter contaminated by chickens with RSS and reported a 70% decrease in weight in the RSSexposed group compared with the unexposed controls. The nucleic acid specific for CAstV and ANV-1 and ANV-2 were detected in RSS exposed birds indicating that astroviruses probably play an important role during RSS.…”

“…The detection/isolation of CAstVs has been reported from broiler chickens exhibiting RSS and from dead-in-shell chicks having hatchability problems (Baxendale and Mebatsion, 2004;Smyth et al, 2009;Pantin-Jackwood et al, 2011;Kang et al, 2012;Koo et al, 2013;Smyth et al, 2013;Mettifogo et al, 2014;SajewiczKrukowska et al, 2016). In most of these studies, CAstVs have been detected using reverse transcription PCR (RT-PCR) and/or quantitative RT-PCR targeting ORF1b or ORF2 genes.…”

RETRACTED ARTICLE: Immunosuppressive interactions of viral diseases in poultry

“…Lymphocyte depletion in lymphoid tissues occurs in turkeys with PEMS (Jindal et al, 2010). Turkey enteric coronavirus is associated with PEMS and turkeys inoculated with coronavirus and E. coli developed lymphocyte necrosis and depletion in the bursa of Fabricius (Kang et al, 2012). Thymus atrophy is associated with PEMS, and it occurs in turkeys inoculated with Astrovirus (Grgić et al, 2011).…”

“…A small round virus, possibly an enterovirus or Astrovirus, can replicate in lymphoid tissues of turkeys, causing lymphocyte necrosis and depletion of lymphoid organs, and corresponding reductions in lymphocyte subpopulations in circulating blood (Hoerr, 2010). Virulent strains of avian Reovirus cause atrophy of lymphoid tissues and interfere with humoral immunity (Kang et al, 2012). Reoviruses can replicate in monocytes but not in lymphocytes; thus, the lymphoid atrophy is not caused by reovirus tropism specifically for lymphocytes in contrast to IBDV, CAV, MDV, and some of the other enteric viruses.…”