Like probably many other public health professionals, I heard about Zikavirus for the first time in October 2015 when Brazil reported an unusual number of cases of microcephaly among newborns. This report triggered a train of public health investigations. On February 1, 2016 the World Health Organisation (WHO) declares that the recent association of Zika infection with clusters of microcephaly and other neurological disorders constitutes a Public Health Emergency of International Concern.
I remember many questions still being unanswered after the report from Brazil, in particular about the causality in the association between Zikavirus infection and microcephaly. The questions are representative of the type of uncertainty that surrounds a newly emerged public health threat. Some of them are part of the obligatory questions in any outbreak investigation (is this an outbreak? what exactly is the case definition? is the diagnosis confirmed? what is the validity of the diagnostic test? who is at risk? what are the main transmission routes? etc, etc). In addition to outbreak investigations other population based research projects are needed. Such as establishing seroprevalence, vector distribution, behavioral studies, forensic pathology etc. The questions about causality are much harder to answer than establishing associations.
The WHO posted a very interesting Zikavirus Timeline. Worth your time if you want to remind yourself of the key issues around this topic.