A warning from the World Health Organisation (WHO) that the Zika virus is "spreading explosively" has global implications. Although a mild illness for most of the four million people who could be infected by the end of the year, it's apparent effect on pregnant women is a source of concern.
The infection has been linked to the development of unusually small heads (microcephaly)and brain damage in newborns. And while a potential causal relationship must await further research, a spike in microcephaly cases has been temporally related to an increase in Zika infection among pregnant women in Brazil and French Polynesia.
A mosquito transmitted infection originally discovered in the Zika forest in Uganda in 1947 the virus is common in Africa and Asia; its spread westward began in May of last year.
Related to dengue fever and the West Nile virus, both of which have also been increasing their geographic footprint in recent years, the explosion in Zika virus infections is yet another reminder of how changes in microbial behaviour can threaten human health.
The WHO has been rightly criticised for its slow initial response to the recent outbreak of Ebola infection in West Africa. And while the high mortality of that virus is unlikely to be replicated in the Zika outbreak, the absence of any treatment means the economic and social damage could be significant.
Pregnant women should not travel to affected areas, which include major tourist destinations in the Caribbean and South America. Some experts are advising caution for women of child-bearing age, reflecting the fact that one half of all pregnancies are unintended. They advise that "strict" birth control be practised when travelling in the affected regions.
The WHO must support further research into the Zika virus, including vaccine development and whether it may be spread via blood transfusion or semen. And it must take a proactive leadership role in managing the outbreak, demonstrating that real lessons have been learned from its poor management of the Ebola epidemic.