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In France, the screening for human T-cell leukemia/ lymphoma virus type 1 and 2 (HTLV-1 and HTLV-2) during the donation of human milk has been carried out from 1992 with the application of the circular DGS 24 November 1992. The screening for antibodies against these viruses is regulated and done systematically during every donation of milk. Breast feeding being the main mode of transmission of the HTLV-1, the last ministerial decree of 25 August 2010 has made the screening test compulsory for the anonymous donation and for the personalized donation (of a mother for her own child) from all women including those affected by the infection. The milk delivered by milk banks is pasteurized (62.5 °C for 30 minutes) before freezing at -18 °C, which inactivates the pathogens. This double means of prevention of the transmission of the HTLV-1 paradoxically seems disproportionate in the absence of any precautionary measure in the case of direct breast-feeding and the use of mother's raw milk. Indeed, in most neonatal intensive care units in maternity hospitals, unpasteurized milk is administered to the neonates without any systematic preliminary testing of the serological HTLV-1 status of the mother. An increased sensitization of the community of the obstetricians, midwives and neonatologists by the Association of the Milk Banks of France (ADLF) and the Société de pathologie exotique could address the issue of screening for HTLV-1 in "donated" milk and breast-feeding.

The transmission of unwanted infection agents to patients, through white blood cells, in blood products is now well established. Therefore the leukodepletion procedure undertaken in blood banks is justified. Leukodepletion prior to transfusion prevents the transmission of leukocyte-associated viruses such as CMV, EBV and HTLV 1 and 2 of viruses present both in plasma and inside leukocytes such as HTLV 1 and 2 viruses and B 19 parvovirus. The mechanism of the immunosuppressive effect of transfusion is still uncertain. The risks of transmitting bacterial diseases through blood transfusions is also a well-known source of concern, particularly the transmission of Yersinia Enterocolitica. However such an event seems to be prevented through leukocyte depletion by filtration when these procedures are performed after a hold of whole blood at 22 degrees C for 6 to no longer than 24 hours. Leukocyte-free blood components prepared by filtration may have a sufficiently reduced rate of infection to provide adequate prophylaxis. In any case the final number of leukocytes should be < or = 10(6) per unit of blood product. Leukocyte filtration must be performed before the onset of a disintegration process of granulocytes.

Human T cell leukemia virus type I and II are endemic in South West Japan and in large parts of the equatorial belt in Central and South America, in Africa, and in some Pacific islands, areas where 1 to 5% of the general populations are infected. Pockets of high prevalence up to 15% and even 35% can be observed. The transmission of HTLV-I includes: maternal to offspring through breast feeding, sexual mainly from men to women and through blood exchange (blood transfusion, intravenous drug abusers, etc.) The diseases being proven to be caused by HTLV-I, include acute adult T cell leukemias as described in Japan, in 1977, in which the HTLV-I provirus is clonally integrated in leukemic cells, and a progressive spastic encephalomyelopathy named TSP/HAM, frequent in HTLV-I endemic areas, and in which an active viral replication takes place. No specific treatment being available, vaccine development, more feasible than for HIV, is critical since 8 to 12% of seropositive individuals develop HTLV-I associated diseases.