Ovine Pulmonary Adenomatosis (OPA) is a contagious, neoplastic, pulmonary disease of sheep characterized by hyperplasia and hypertrophy of alveolar type II pneumocytes and epithelial (Clara) cells of the lung. It is caused by Jaagsiekte Sheep virus belongs to the Retroviridae family. A endogenous retrovirus (enJSRV), closely related to JSRV, is present in domestic and wild sheep and goats. The presence of endogenous virus can explain the absence of circulating antibodies in terms of immune-tolerance. Data on the natural transmission of JSRV-infection are scarce. The virus is transmitted between animals by close contact, mainly through aerosolized particles. The incubation period ranges between 2 and 4 years and may vary according to the age of the animals. The rapid development of tumoral lesions in young animals suggests a greater susceptibility of the developing lung to JSRV. Some studies would show a high susceptibility to the infection in the lamb newborn while lambs inoculated at 10 weeks of age were more refractory to tumour development . However, recently, a case of horizontal infection in an adult sheep has been described . A longitudinal study on the occurrence of OPA in sheep of a farm in Enna (Sicily) is reported. The flock, composed by 750 animals of Valle del Belice, Comisana, Barbaresca and Pinzirita breeds is managed semiintensively. Respiratory pathology is manifested in a period that has gone since March 2006 to October 2008 in 8 females Valle del Belice lactating sheep. 6 of these sheep originated from a group of 60 animals introduced in breeding two years previously while 2 belonged to the contingent already present in farm. Of these, at the time of the clinical signs appearance, 1 female had 3 years of age and could have been infected in the first months of life but the second had been born 2 years before the introduction of the hypothetically infected group. Any case reportable to APO had ever been described in the flock and therefore we can hypothesize that this animal has been infected in adult age. The authors describe the clinical and anatomo-histopathological features. The natural cycle of infection and the susceptibility to the infection is discussed.

Occurrence of Ovine Pulmonary Adenomatosis (OPA) in a flock in Sicily – contribution to the knowledge on the epidemiological characteristics

FOTI, Maria;RINALDO, Donatella;GIACOPELLO, CRISTINA;FISICHELLA, Vittorio;
2009-01-01

Abstract

Ovine Pulmonary Adenomatosis (OPA) is a contagious, neoplastic, pulmonary disease of sheep characterized by hyperplasia and hypertrophy of alveolar type II pneumocytes and epithelial (Clara) cells of the lung. It is caused by Jaagsiekte Sheep virus belongs to the Retroviridae family. A endogenous retrovirus (enJSRV), closely related to JSRV, is present in domestic and wild sheep and goats. The presence of endogenous virus can explain the absence of circulating antibodies in terms of immune-tolerance. Data on the natural transmission of JSRV-infection are scarce. The virus is transmitted between animals by close contact, mainly through aerosolized particles. The incubation period ranges between 2 and 4 years and may vary according to the age of the animals. The rapid development of tumoral lesions in young animals suggests a greater susceptibility of the developing lung to JSRV. Some studies would show a high susceptibility to the infection in the lamb newborn while lambs inoculated at 10 weeks of age were more refractory to tumour development . However, recently, a case of horizontal infection in an adult sheep has been described . A longitudinal study on the occurrence of OPA in sheep of a farm in Enna (Sicily) is reported. The flock, composed by 750 animals of Valle del Belice, Comisana, Barbaresca and Pinzirita breeds is managed semiintensively. Respiratory pathology is manifested in a period that has gone since March 2006 to October 2008 in 8 females Valle del Belice lactating sheep. 6 of these sheep originated from a group of 60 animals introduced in breeding two years previously while 2 belonged to the contingent already present in farm. Of these, at the time of the clinical signs appearance, 1 female had 3 years of age and could have been infected in the first months of life but the second had been born 2 years before the introduction of the hypothetically infected group. Any case reportable to APO had ever been described in the flock and therefore we can hypothesize that this animal has been infected in adult age. The authors describe the clinical and anatomo-histopathological features. The natural cycle of infection and the susceptibility to the infection is discussed.
2009
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/5261
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