Gastrointestinal Pathogenicity of Adenoviruses and Reoviruses Isolated from Broiler Chickens in Alabama

Abstract

Abstract. Adenoviruses and reoviruses isolated from commercial broiler chickens were evaluated for gastrointestinal pathogenicity in specific-pathogen-free Leghorn chickens. The viruses were originally isolated from either the proventriculus or a gastrointestinal pool of tissues of broiler chickens with proventriculitis or enteritis. Isolates were cloned by terminal dilution. Day-old chickens were inoculated by oral and ocular routes with undiluted tissue culture fluids (titers of 10 2 -10 4 TCID 50 /ml) and then examined at necropsy on days 5, 10, and 15 postinoculation. Chickens in all virus groups (but not the control group) developed wet, unformed fecal droppings that persisted for the duration of the study. Mild lesions occurred in reovirus-inoculated chickens and included hyperplasia of lymphocyte aggregates in various organs and mild gizzard erosions. Chickens inoculated with adenovirus isolates developed marked gizzard erosions and necrotizing pancreatitis as well as mild proventriculitis. Intranuclear viral inclusion bodies occurred in gizzard epithelium and pancreatic acinar cells at the sites of lesions. Lymphocytic atrophy occurred in the bursa of Fabricius. Respective viruses were reisolated from proventriculus and duodenum collected from chickens of each group; no viruses were isolated from controls. Under the conditions of this study, adenovirus isolates were more pathogenic than the reovirus isolates in the digestive system.Digestive system signs and lesions often are observed in broiler chickens submitted for laboratory evaluation because of impaired weight gain and feed conversion, feed passage, and watery feces. Various lesions have been identified in the proventriculus, gizzard, intestines, pancreas, and liver in the course of these investigations. Adenoviruses and reoviruses are commonly isolated from the affected viscera, particularly from the proventriculus and duodenum in birds with lesions in these organs.Digestive tract disease in broiler chickens in the southeastern United States has several causes and clinical and pathologic expressions. 7 Reoviruses have a causative link with digestive syndromes, but mainly these syndromes are caused by certain reovirus strains of high pathogenicity. 23 The role of adenoviruses in digestive disease of chickens is equivocal, 18 which has made it difficult to interpret virus isolation results from chickens with digestive system signs and lesions.The purpose of this study was to extend routine diagnostic investigation of digestive tract disease by attempting to assess the pathogenic potential of viral isolates in susceptible chickens.

Pathogenicity by Parenteral Injection of Fowl Adenovirus Isolated from Gizzard Erosion and Resistance to Reinfection in Adenoviral Gizzard Erosion in Chickens

“…It has been reported that two strains of FAV cause gizzard erosion and necrotizing pancreatitis without hepatic or intestinal lesions when FAV is administered experimentally by oral inoculation. 12 The observed pancreatic lesions were clearly different from the lesions of malabsorption syndrome (runting and stunting syndrome) such as atrophy, occlusion of the pancreatic ducts, interstitial fibrosis, and dilation of the acinar lumens. 13,23 Inclusions in the epithelial cells of the biliary passages were observed in four chickens in trial 1.…”

Adenoviral Gizzard Erosion in Commercial Broiler Chickens

“…Some FAVs that had originally been isolated from either the proventriculus or a gastrointestinal pool of the tissues of broiler chickens caused gizzard erosions by experimental infection. 22 In our previous studies, outbreaks of adenoviral gizzard erosion (AGE) in slaughtered broiler chickens in Japan were examined, and an FAV serotype-1 named FAV-99ZH was isolated from the gizzard lesions with adenoviral intranuclear inclusion bodies; 31 also, AGE was experimentally reproduced in chickens inoculated with FAV-99ZH. 28 However, only a small number of specific-pathogen-free (SPF) white leghorn chickens were used, and no immunohistochemical examination was done during the experimental infection.…”

Características clínicas e anatomo-histopatologicas da infecção experimental mista por Orthoreovirus aviario e Mycoplasma synoviae em frangos de corte

“…Apesar do ARV não ter sido detectado nestes tecidos, não exclui sua atividade em uma fase inicial da infecção, que poderia de alguma forma contribuir para o agravamento das lesões causadas pelo MS (Rosenberger & Olson 1997). A presença de inϐiltrado inϐlamatório mononuclear no proventrículo, caracterizando um quadro de proventriculite, possivelmente está associado à via de inoculação (via oral) do ARV (Rosenberger & Olson 1997, Lenz et al 1998. Inϐiltrado linfohistiocitário intenso principalmente no espaço porta e presença de heteróϐilos foi observado no ϐí-gado, além de pontos de necrose hepática focal em 43,75% (7/16) dos frangos.…”