Retroviral coinfection (Jaagsiekte and Maedi-Visna viruses) in sheep with pulmonary tumors in Transylvania (Romania): retrospective study on 82 cases.

Abstract

Ovine pulmonary adenocarcinoma (OPA) is an important viral-induced neoplasiain sheep caused by exogenous Jaagsiekte sheep retrovirus (exJSRV). Coinfectionof exJSRV and Maedi-Visna virus (MVV) is reported in OPA cases, but itsworldwide distribution and significance on lung pathology is not yet completelyunderstood. This study aimed to investigate the MVV coinfection rate in 82exJSRV-related OPA cases, and their pathological effects on lung parenchymain slaughtered sheep in Transylvania (Romania). On gross examination, classicalform of OPA was identified in 92.7%; no changes consisting with MVV interstitialpneumonia were identified in the included cases. The most common histologicaltype of OPA was acinar (58.5%) and the myxoid growths were found in 18 cases.The exJSRV and MMV coinfection rate in examined sheep was 47.6% (39/82). Theassessment of perineoplastic areas from coinfected animals, revealed interstitiallymphoplasmacytic infiltrates in all cases, lymphoid hyperplasia in 60.6% cases(20/33) and fibromuscular hyperplasia in 63.7% (21/33). This is the first reportproviding new data on distribution of OPA coexisting with MVV infection inslaughtered sheep in Romania. We consider that the OPA and MVV coinfectionmay play an important role on the severity of ovine chronic pulmonary diseasesand further studies are needed to confirm this hypothesis.