Survival of Treponema pallidum in banked blood for prevention of Syphilis transmission

Every year, millions of people are exposed to avoidable, life-threatening risks through the trans-fusion of unsafe blood. To determine the survival time of Treponema pallidum in banked donor blood. Two groups of male Wistar rats (group A and B) were inoculated intratesticularly with 0.5ml of artificially infected donor blood (final density of Nichols treponemes: 5×10(5) /ml) stored at 4°C for various periods of time. In group A, a pair each of the rats was injected every 12 hours, starting at 0 hr, up to a maximal storage time of 96 hr. In group B, the rats were injected after 72, 120, 192 and 336 hours of storage of the treponemes-blood mixture. Group C which is a control group was injected with blood only, while group D rats were injected with heat-killed treponemes suspended in blood every 12 hours. The detection of Treponema pallidum IgG/IgM was based on the principle of double antigen sandwich immunoassay, in which purified recombinant antigens are employed sufficiently to identify antibodies to Syphilis. The outcomes of interest included the proportion of Syphilis positive rats and the maximal survival hours of T. pallidum in banked blood. 14 rats (77.8%) out of the 18 rats that were involved in group A developed orchitis and positive serology up to 72 hours of storage time, p