Detection and molecular characterization of chicken parvovirus and chicken megrivirus in layer breeders affected by intestinal dilatation syndrome

Abstract

ABSTRACT Intestinal dilatation syndrome (IDS) is a segmental enteropathy characterized by dilatation of the junction of the ileum and jejunum (Meckel’s diverticulum). IDS severely affects the poultry industry by causing a chronic and irreversible drop in egg laying, reducing feed conversion efficiency, and increasing the mortality rate. The clinical and pathological features of IDS in white laying hens were described, and viral molecular and metagenomic research was conducted. The 50 – to 60-day-old chickens presented pale mucosa, apathy, depression, ruffled feathers, and diarrhoea, accompanied by a 20% loss in fertile egg production, 20% culling of birds, and 5% mortality. The main findings at necropsy were marked intestinal dilatation with intestinal stasis, a narrow distal jejunum in the region of Meckel's diverticulum, and undigested food. Microscopic analysis revealed marked atrophic lymphoplasmacytic and heterophilic enteritis with hyperplastic crypts, ulceration, and heterophilic and lymphoplasmacytic perineuritis. The molecular assays consistently detected the presence of chicken parvovirus in the three segments of the intestine, pancreas, and proventriculus, as well as chicken megrivirus in the intestinal contents. Marked atrophic enteritis with perineuritis and intestinal stasis were associated with clinical manifestations of poor intestinal absorption and secondary bacterial infection. Our data provide useful information about IDS and highlight the importance of further studies to determine the specific role of each detected virus in this syndrome. RESEARCH HIGHLIGHTS IDS presented pathognomonic dilatation of the jejunum up to Meckel's diverticulum. IDS caused weight loss, decreased egg production, and increased culling and mortality. Chicken parvovirus (ChPV) was consistently detected through PCR assays. Chicken megrivirus (ChMV) was consistently detected through viral metagenomics.