Detection of the Maedi Visna Virus in the poplyteal limph nodes of sheep infected by the respiratory route.

In order to verify the presence of Maedi Visna Virus (MVV) in lymph nodes that are not tributary of the viral target organs, popliteal lymph nodes from four experimentally infected sheep have been analysed by immunohistochemistry and PCR. The sheep were infected via tracheal inoculation about three years earlier. No macroscopical and histological lesions have been found in the popliteal lymph node samples, while the viral antigen p25 and a sequence of the LTR gene of MVV have been detected respectively by immunohistochemistry and PCR. These results confirm that MVV infection is not limited to the target organs and show that the virus can replicate in popliteal lymph nodes in absence of detectable lesions.