Pathogenicity of Serotype 8 Fowl Adenovirus Isolated from Gizzard Erosions of Slaughtered Broiler Chickens

Abstract

ABSTRACT. The pathogenicity of serotype 8 fowl adenovirus (FAV), isolated from gizzard erosions of slaughtered broiler chickens, was investigated. In experiment 1, 29 5-day-old specific-pathogen-free (SPF) chickens were inoculated with the isolates of serotype 8 FAV, M013 (group 1) or G0054 (group 2) strain, via an oral route. There were no clinical signs in any of chickens after inoculation, and mild gizzard erosions were observed macroscopically and microscopically in three inoculated chickens of group 2. FAV was recovered f rom gizzards and rectums but was not recovered from pancreas and livers from chickens in both inoculated groups. In experiment 2, 27 1-day-old SPF chickens were inoculated with the G0054 strain by intramuscular route. Five, 6, and 3 inoculated chickens died on days 3, 4, and 5 postinoculation (PI), respectively. Four, 3, 1, and 1 inoculated chickens became moribund with severe clinical sign s such as ruffled feathers, severe depression and closed eyes from days 3 to 6 PI, respectively. Macroscopically, the common characterist ic of the gross lesions of dead chickens and euthanized moribund chickens was discoloration of liver. FAV was recovered from the gizzard, liver, pancreas and rectum. Virus titers in the liver and pancreas were high until day 6 PI. Histologically, necrotizing hepatitis an d pancreatitis with intranuclear inclusion bodies were observed in the inoculated chickens. These results indicate that some strains of seroty pe 8 FAV are able to reproduce not only gizzard erosion by oral inoculation but inclusion body hepatitis (IBH) by intramuscular inoculation. KEY WORDS: gizzard erosion, inclusion body hepatitis, serotype 8 fowl adenovirus.J. Vet. Med. Sci. 66(12): 1561-1566, 2004 The pathogenicity of serotype 8 fowl adenoviruis (FAV) has been reported in field cases of inclusion body hepatitis (IBH) in chickens [7] as well as in experimental reproduction of IBH in specific-pathogen-free (SPF) chickens [6]. Recently, serotype 8 FAV was isolated from gizzards exhibiting gizzard erosion in slaughterhouses [14]. In pervious reports, however, gizzard erosion was reproduced in SPF white leghorn chickens [9,11] and commercial broiler chickens [12] inoculated with serotype 1 FAV isolated from the gizzards of commercial broiler chickens exhibiting gizzard erosion. Moreover, most cases of gizzard erosion that have occurred frequently in slaughterhouses in Japan were caused by serotype 1 FAV infection [14]. Therefore, it was not clear whether or not serotype 8 FAV was the cause of gizzard erosion.The purpose of this study was to investigate the pathogenicity of serotype 8 FAV isolated from eroded gizzard by inoculating SPF chickens with the isolates via oral and intramuscluar routes. MATERIALS AND METHODSVirus: Two isolates of FAV, isolated from gizzard erosions of slaughtered broiler chickens, were cloned three times by means of the terminal dilution method and designated as the M013 and G0054 strains. These strains were propagated in primary chicken kidney (CK) cells and used for chicke...

Analysis of adenovirus strains isolated from poultry in Poland

“…The role of adenoviruses as the opportunistic factors is indicated (7). They can cause asymptomatic infections, but also they are an aetiological agent of diseases such as inclusion body hepatitis -IBH (6), hydropericardium hepatitis syndrome -HHS (7), gizzard erosion and ulceration (GEU) (20), and pancreatitis (24). Adenoviruses can be one of the reasons of immunodeficiency.…”

Pathogenicity of Fowl Adenovirus Isolated from Gizzard Erosions to Immuno-Suppressed Chickens

“…The gizzard lesions were reproduced in broiler and specific pathogen-free (SPF) chickens by oral infection with the isolated FAVs [6][7][8]15]. However, some of the experimentally infected birds failed to show the gizzard lesions [5,15]. On the other hand, FAV has been well known as an agent of inclusion body hepatitis, which was rather facilitated in immuno-deficient birds caused by infectious bursal disease virus (IBDV) infection [2,5].…”

“…However, some of the experimentally infected birds failed to show the gizzard lesions [5,15]. On the other hand, FAV has been well known as an agent of inclusion body hepatitis, which was rather facilitated in immuno-deficient birds caused by infectious bursal disease virus (IBDV) infection [2,5]. In this study, the pathogenicity of FAV strain isolated from gizzard erosion to immuno-deficient chickens was investigated using IBDV-infected or cyclophosphamide (CY)-treated chickens.…”

“…All FAVs, which have been isolated so far from gizzard erosion, were restricted to serotypes 1 or 8 only [6,15], but the FAVs from IBH belong to many serotypes including serotype 1 and 8 [5]. In addition, adenoviral gizzard erosion had not been recognized until the first report in 1993 [14].…”

Occurrence of Adenovirus Field Strains in Birds Infected with Marek’S Disease Virus

“…In one case they can cause asymptomatic infections, in another they are an aetiological agent of diseases such as inclusion body hepatitis -IBH (6,19) or hydropericardium hepatitis syndrome -HHS (14). The viruses have been also isolated from birds with respiratory tract diseases (22), gizzard erosion and ulceration (GEU) (5,21,23), and pancreatitis (30). Adenoviruses can be the reason of immunodeficiency in young chicks, that can further lead to suppression of the immunity after the vaccination against Marek's disease.…”