I have been writing about Zika since the time before it became part of the public vernacular. My first piece,"Zika is Possibly the Scariest Virus Since HIV," discussed a number of factors that would determine whether the virus was a real threat to the United States, or just another scare that ended up being nothing. There are far more cases of the latter than the former.
Perhaps the most important determinants of which way this goes is whether the virus could be transmitted by the common Culex family of mosquitoes, and how efficient this transmission would be. All cases to date have been due to the Aedes species of mosquito, which is uncommon in the U.S.
But this may change. Scientists have demonstrated that Culex quinquefasciatus, a mosquito that is 20-times more common than Aedes, can become infected with the virus, at least in a lab. This does not have to mean that the Culex family will play a significant part in transmission of the virus to large areas of the U.S., but it is nonetheless disturbing.
Speaking of disturbing, the following map from the Lancet gives a prediction (based on modeling) of the range of infection in the Americas if the Culex mosquito becomes a vector for Zika. There is nothing even remotely comforting about this. Roughly half of the U.S. would be at risk of contracting the infection. The yellow represents seasonal outbreaks, while the orange areas have a year-round risk. Keep in mind that modeling may or may not represent reality.
Next in this series: DDT vs. DEET. Facts that will surprise you.