Caprine astrovirus detected in conjunction with necrotizing enterocolitis in goat kids in Indiana

An outbreak of enteric disease occurred in a herd of Nigerian Dwarf goats in Indiana, USA, in March 2024. Kids 2–5-wk-old had severe diarrhea that did not respond to treatment. Two kids that underwent postmortem examination had gross and histologic evidence of fibrinonecrotizing typhlocolitis. Ancillary testing for known causes of enterocolitis in goats did not yield any potential causes. High-throughput sequencing (HTS) was performed to identify possible novel viral pathogens. Total nucleic acids were extracted from fresh intestine for HTS analysis, and a subset of astrovirus reads was obtained and assembled. This result was confirmed by HTS of total RNA extracted from formalin-fixed paraffin-embedded material in a separate laboratory, enabling the assembly of a full-genome astrovirus sequence of 6,285 nucleotides. This novel astrovirus strain was designated caprine astrovirus (CapAstV; family Astroviridae , genus Mamastrovirus ) Indiana/2024. No other viruses were identified via either method. In situ hybridization for CapAstV Indiana/2024 RNA was performed to link the pathogen and lesion. Positive signal was detected within the enterocyte cytoplasm in intestinal sections, as well as presumed macrophages within the lamina propria. We confirmed that CapAstV Indiana/2024 infected goat enterocytes and occurred in conjunction with severe necrotizing enteric disease.