[Lentivirus expression at the moment of lambing modifies the leukocyte number in the milk of multiparous ewes].

Lambing in small ruminants is a time of high lentivirus expression; infected mononuclear phagocytes are frequent in colostrum and milk. We have studied mammary secretions in 5 multiparous ewes and shown that infected macrophages in milk are accompanied by an augmentation of leucocyte number. The lymphocyte CD8 subpopulation increased in size simultaneously with the onset of infected cell excretion. The udder infection by coagulase negative staphylococci did not modulate milk lymphocyte content. Although infected cell excretion was restricted to one half of the udder, virus-specific lesions were found in both udder halves. Milk leukocytes changes are a marker of infected macrophage presence; they do not control lentivirus spread.