Following blood transfusion, there is a risk of transfusion-transmitted infectious diseases (TTID), despite current advanced screening technologies. Infectious agents involved are very diverse and include hepatitis B (HBV), hepatitis C (HCV), human immunodeficiency (HIV-1/2), human T-cell lymphotropic (HTLV-I/II), Cytomegalo- (CMV), Parvo- B19, West Nile (WNV) and Dengue viruses. Trypanosomiasis, malaria, and Transmissible Spongiform Encephalopathy (TSE) also belong to TTID. TTID can be reduced by donor exclusion, screening for serological infection markers or nucleic acid testing (NAT) by viral gene amplification. Despite this, blood-borne infectious agents are transmitted through transfusion of infected blood donated by apparently healthy and asymptomatic blood donors.