Detection of enteric viruses in pancreas and spleen of broilers with runting-stunting syndrome (RSS)

Abstract

RESUMO.-[Detecção de vírus entéricos em pâncreas e baço de frangos com a síndrome de nanismo e raquitismo (RSS).]A doença entérica é um problema multifatorial em galinhas que causa alterações gastrointestinais, conversão alimentar elevada e deficiência de crescimento.Nos últimos anos, os vírus entéricos foram associados à doença entérica; casos reportados mostraram a infecção de um único vírus e também infecções concomitantes durante os surtos sugerindo a presença de múltiplos fatores etiológicos nas doenças entéricas. Este estudo mostra uma alta taxa de detecção dos vírus entéricos em amostras de pâncreas e baço de um surto de enterite e má-absorção em 16 lotes de frangos (n=80 frangos). O vírus de nefrite aviá-ria (ANV) foi o vírus mais detectado, estando presente em 75% dos lotes seguido pelo rotavírus aviário grupo A (ART--A) em 68,75% dos casos, e pelo astrovirus (CAstV) e parvovírus aviários (ChPV), ambos em 43,75% das amostras. Os vírus estavam presentes no pâncreas dos lotes positivos em percentuais elevados: 100% para ART-A e CAstV; 91,7% para ANV, e em 57,14% para ChPV. Em contraste, somente 16,7% e 57,14%, em amostras de intestino, foram positivos para ANV e CAstV, respectivamente. Reovírus aviário Enteric disease is a multifactorial problem in chickens, which causes gastrointestinal alterations, elevated feed conversions and impairment. In the last years, several enteric viruses were implicated in enteric disease; case reports have shown their presence alone or in concomitant infections during outbreaks and have suggested that they might be determining factors in the aetiology of enteric disease. This study shows high detection rates of enteric viruses in the pancreas and spleen in samples from an outbreak of enteritis and malabsorption in 16 chicken flocks (n=80 broilers). Avian nephritis virus (ANV) was the most ubiquitous virus, present in 75% of the flocks followed by avian rotavirus group A (ART-A) with 68.75%, and by chicken astrovirus (CAstV) and chicken parvovirus (ChPV) in 43.75% of samples. Viruses were present in the pancreas of positive flocks at extremely high rates: 100% for ART-A, 91.7% for ANV, 100% for CAstV and 57.14% for ChPV. By contrast, only 16.7% and 57.14% of intestine samples were positive for ANV and CAstV, respectively. Avian reovirus (AReo) and avian adenovirus group 1 (FAdV-1) were not detected. These results suggest that high viral detection rates in pancreas samples may be a result of viremia during enteric disease, with subsequent damage of the exocrine pancreas, leading to runting-stunting syndrome (RSS).INDEX TERMS: Broiler, enteric viruses, detection, pancreas, spleen, runting-stunting syndrome, RSS.

Development of a Sensitive Real-Time Fast-qPCR Based on SYBR® Green for Detection and Quantification of Chicken Parvovirus (ChPV)

“…Similar results were found in the present study in which apparently healthy chickens also showed high viral concentrations [ 22 ]. ChPV has been detected in chickens independently of zootechnical interest and in many regions around the world with high chicken production, such as Europe [ 10 , 17 , 18 ], China [ 35 ], South Korea [ 36 ], North America [ 8 , 37 , 38 ], Brazil [ 9 , 16 , 24 , 25 ], and Ecuador [ 26 , 38 ]; however, its presence remains unknown in the rest of South America. The present study also showed that the virus was detected at earlier and later ages in chickens, demonstrating that virus dissemination can occur at any time [ 21 ].…”

“…All of these assays showed a high sensitivity for ChPV detection and quantification. In the Brazilian chicken flocks in the recent years, many outbreaks of RSS have been reported where ChPV has been detected, and the NS gene was sequenced, confirming that the sequences belonged to ChPV, identifying the virus in young and old chickens as early as the first day of infection [ 9 , 16 , 24 , 25 , 26 ]. Enteric diseases cause economic losses in poultry, the depreciation of poultry flocks, and increased susceptibility to other diseases, so a rapid, efficacious, affordable, reliable assay should be standardized for the diagnosis of the etiological agent [ 27 , 28 , 29 ].…”

Avian Group D Rotaviruses: Structure, Epidemiology, Diagnosis, and Perspectives on Future Research Challenges

“…Earlier studies on rats have shown the capacity of AvRVs to disseminate and replicate in different organs, such as the liver, spleen, and pancreas; however, the mechanism by which RV escapes the gastrointestinal tract and reaches other organs remains unknown [ 55 ]. Recently, the extra-intestinal presence of avian RVA in the pancreas and spleen of broilers with RSS has also been reported [ 26 ]. However, there is no such report for RVD.…”

“…AvRVs cause colossal losses to the poultry industry, as they result in decreased feed adsorption, ultimately leading to reduced weight gain [ 8 ]. Apart from the gastrointestinal tract, RVs have also been detected in the pancreas and spleen of broilers with runting and stunting syndrome (RSS) [ 26 ]. Runting and stunting syndrome, which is caused by many different agents, including reovirus, astrovirus, coronavirus etc., has a highly negative impact on poultry sector.…”

Enteric Virus Diversity Examined by Molecular Methods in Brazilian Poultry Flocks

“…Enteric viruses are the etiological agents for a series of health disturbances for commercial chickens around the world. They cause severe economic losses for the poultry industry because they negatively affect productive parameters, causing growth retardation, low feed consumption, high mortality, poor egg and meat production, and Runting-Stunting Syndrome (RSS) [ 1 , 2 , 3 , 4 ]. These kinds of infections affect mostly young birds, but it is common to find viral infections in birds of all ages, including broilers, layers, and breeders [ 5 ].…”