Pathogenesis of Ornithobacterium rhinotracheale in egg-laying hens with coexisting infectious bronchitis virus and Escherichia coli infections

Abstract

Ornithobacterium rhinotracheale (ORT) is recognized as an important respiratory pathogen in turkeys and chickens. The severity of the disease is worsened when birds have coexisting infections with other respiratory pathogens. The objectives of this study were to investigate the pathogenesis of ORT infection with exposure to infectious bronchitis virus (IBV), Escherichia coli, or both in laying chickens. A total of 160 eight-week-old specific pathogen-free White Leghorn chickens were exposed experimentally to 1 of 7 treatments: ORT alone; E. coli alone; IBV alone; ORT + E. coli; ORT + IBV; IBV + E. coli; or ORT + IBV + E. coli. The clinical signs and pathological changes were evaluated in birds from all groups. Birds exposed to ORT or E. coli alone did not show any overt clinical signs. Birds exposed to IBV, ORT + IBV, IBV + E. coli, and ORT + IBV + E. coli exhibited clinical signs that varied from depression and nasal discharge to mortality. The ORT + IBV + E. coli-infected birds exhibited gross lesions, which included hemorrhagic tracheitis, fibrinous pneumonia, airsacculitis, pericarditis, and peritonitis. Histopathological studies of this group revealed distinct pathological changes. Immunohistochemistry staining demonstrated the presence of ORT antigens in the tracheas and lungs of the ORT + IBV + E. coli-infected birds. Mortality after ORT infection was noticed only in the ORT + IBV + E. coli group. We conclude that IBV and E. coli infections exacerbate ORT pathogenesis in adult laying hens. We also conclude that ORT persists in tissues such as the infraorbital sinuses for longer periods without causing significant respiratory disease by itself. This presence of ORT may predispose birds to the development of peritonitis and death with subsequent IBV and E. coli coinfections.

<i>Ornithobacterium rhinotracheale</i> Infection in Poultry: an Updated Review

“…In turkeys, unilateral and bilateral consolidations of lungs due to pneumonic or bronchopneumonic lesions with fibrinous exudate of the pleura have been found Thachil et al, 2009;Tabatabai et al, 2010). Mild or severe tracheitis, fibrinosuppurative thoracic and/or abdominal airsacculitis, pericarditis, and peritonitis have also been described in turkeys Chin and Charlton, 2008;Thachil et al, 2009).…”

“…According to experimental reproductions of the disease, the clinical signs are seen 24~48 h post-inoculation . Ornithobacterium rhinotracheale infection has been reported mostly in broiler chickens and turkeys, and less frequently in other avian species such as pheasants, quails, gray partridges, chukar partridges, red-legged partridges, guinea fowls, ostriches, rooks, pigeons, ducks, geese, and gulls (van Empel and Hafez, 1999;Moreno et al, 2009 Sakai et al, 2000;Marien et al, 2005;2007;Thachil et al, 2009;Gornatti Churria et al, 2012;Pan et al, 2012). The severity of clinical signs, the duration of the disease and the mortality caused by O. rhinotracheale outbreaks are extremely variable, and can be influenced by a wide range of environmental factors .…”

“…In order to investigate the role and pathogenesis of O. rhinotracheale in poultry, several works of experimental reproductions by using turkey embryo, chicken, turkey, layer hen, and quail models with or without the involvement of other bacterial and/or viral respiratory pathogens have been reported (Goovaerts et al, 1998;van Empel and Hafez, 1999;van Veen et al, 2000b;Marien et al, 2005;Eroksuz et al, 2006;Thachil et al, 2009;Pan et al, 2012). Intra-tracheal, intra-thoracic, intranasal, intravenous, and oculonasal administration routes were used to inoculate birds with the causing agent.…”

“…Mild or severe tracheitis, fibrinosuppurative thoracic and/or abdominal airsacculitis, pericarditis, and peritonitis have also been described in turkeys Chin and Charlton, 2008;Thachil et al, 2009). Swelling of the liver and spleen, degeneration of the heart muscle, and infection of vertebrae and joints have been observed in some cases of O. rhinotracheale infection in turkeys .…”

Hallazgos Clínicos y Anatomopatológicos en Aves White Leghorn Ocasionados por Ornithobacterium rhinotracheale y Escherichia coli en Condiciones Controladas

“…Desde la década del 90 se viene notificando la emergencia de serovares de Ornithobacterium rhinotracheale en infecciones respiratorias en pollos de ceba, pavos y gallinas ponedoras en menor cuantía, en países como EEUU, México, Argentina, Brasil, India, Perú e Irán, además de países africanos (Van Empel y Hafez, Existen reportes sobre las manifestaciones clínicas y lesiones del sistema respiratorio producidas por O. rhinotracheale en diferentes categorías y propósitos de crianza de aves (pollos de ceba y pavos, fundamentalmente). Estos signos son más severos cuando esta bacteria participa con otros agentes microbianos, como E. coli (Droual y Chin, 1996), Bordetella avium (Charlton, 1999), los adenovirus grupo I (Travers et al, 1996), y los virus de la enfermedad de Newcastle (ENC), bronquitis infecciosa (BI), anemia infecciosa y enfermedad infecciosa de la bolsa de Fabricio (EIB); estos dos últimos considerados como agentes inmunosupresores que afectan la respuesta inmune del hospedero (Thachil et al, 2009 …”