Demonstration of Pigeon Circovirus Infection in Western-Libya, Based on Histopathology, Electron Microscopy and Apoptosis

Pigeon circovirus (PiCV) infection associated with high morbidity and mortality have been recognized in a large rearing loft for racing pigeons in El-Nekat El-Khams-Western Libya. There exist a number of data indicating that immunosuppression with subsequent infections with various secondaiy microbial infections are a consequence of PiCV infection. PiCV diagnosis was based on light and transmission electron microscopical observation of characteristic botryoid ciystalline globular inclusions of circovirus in bursa of Fabricius as well as the potential concurrent lesions of other primary and secondaiy lymphoid tissues. Histopathological findings were suggestive of primary bursotropism of pigeon circovirus, followed by secondary systemic spread from the bursa of Fabricius, particularly to non-bursal lymphoid organs. The last stage of the disease was associated with various secondaiy (particularly bacterial) infections. In situ detection of apoptosis in the bursa of Fabricius indicated that PiCV was concomitant with an increase in bursal lymphocytic apoptotic events related to viral infection and leading to severe acquired immunosuppression. It was concluded that the present trial has brought an ultimate proof of the presence of pigeon circovirus in Western-Libya and further investigations and a method based on the presence of viral DNA using in situ Hyperdization or nested PCR are needed to evaluate the prevalence of PiCV.