Pathogenesis of an Avian Reovirus Isolate Displaying Enteric and Arthritic Tropisms

Area of Science:

• Veterinary Virology
• Avian Pathology

Background:

• Avian reoviruses (ARVs) are significant pathogens in poultry.
• Genetic cluster (GC) 2 ARVs are frequently isolated from clinical cases, causing tenosynovitis and malabsorption.

Purpose of the Study:

• To investigate the pathogenesis of an ARV GC 2 isolate in chickens.
• To determine the distribution and cellular tropism of ARV GC 2 following experimental inoculation.

Main Methods:

• Oral and footpad inoculation of chickens with an ARV GC 2 isolate.
• Quantitative reverse transcriptase PCR (RT-qPCR) for viral RNA detection.
• In situ hybridization (ISH) and histopathology for tissue analysis.

Main Results:

• ARV RNA was detected in the digital flexor tendon, heart, lung, liver, spleen, kidney, duodenum, cecum, cloacal bursa, and thymus.
• Highest viral loads were in the intestinal tract (36-72 hpi).
• ARV was identified in intestinal villous enterocytes, bursal follicle-associated epithelial (FAE) cells, and synovial membrane.

Conclusions:

• ARV GC 2 infects a wide range of tissues, with a predilection for the intestinal tract.
• The virus targets enterocytes and synovial tissues, indicating potential dual enteric and arthritic roles.
• Further research is needed to identify specific infected cell types in the intestine and synovium.