Emerging infectious disease agents and blood safety in Australia: spotlight on Zika virus

Emerging infectious diseases (EIDs) are infectious diseases whose incidence has increased in humans in the past 20 years or could increase in the near future. EID agents may represent a threat to blood safety if they infect humans, cause a clinically significant illness, include an asymptomatic blood phase in the course of infection, and are transmissible by transfusion. EID agents are typically not well characterised, but there is a consensus that we can expect ongoing outbreaks. Strategies to manage the risk to blood safety from EIDs include ongoing surveillance, regular risk assessments, modelling transfusion transmission risk, and deferral of donors with a recent travel history to outbreak areas. The 2015-16 Zika virus (ZIKV) outbreak in the Americas is the largest reported ZIKV outbreak to date, and it highlights the unpredictable nature of EID outbreaks and how quickly they can become a major public health problem. This ZIKV outbreak has provided evidence of a causal link between the virus and microcephaly in newborns. In assessing the potential risk of ZIKV to blood safety in Australia, it should be noted that a relatively small number of imported ZIKV infections have been reported in Australia, there have been no reported cases of local ZIKV transmission, and the geographical distribution of the potential ZIKV mosquito vector in Australia (Aedes aegypti) is limited to northern Queensland. Moreover, reported transfusion-transmitted ZIKV cases worldwide are rare. At present, ZIKV represents a low risk to blood safety in Australia.