Oncornavirus particles in lymphoid cultures from a howler monkey with Herpesvirus saimiri-induced disease.

Budding and extracellular oncornavirus particles were observed in cells of lymphoid cultures derived from the spleen, lymph node, and blood of a howler monkey (Alouatta caraya) that developed a malignant lymphoproliferative disease after infection with Herpesvirus saimiri. The various possible sources of origin of these particles are discussed.