Up until now, all reported cases of the Zika virus in the continental United States have been traced back to travel abroad. But a recent Florida Zika case might be the first local transmission case in the country — meaning that it may have been carried by local mosquitoes rather than contracted by sexual intercourse or a mosquito bite in a Zika-affected country. If that is the case, it means that the spread of the disease will be much more difficult to track and contain from here on out.

According to Wired, the investigation will have to confirm whether the mosquitoes where the woman lives (southern Florida) carry the Zika virus. Already they have begun testing the main Zika carriers Aedes egypti and Aedes albopictus mosquitoes. Sharon Irsen, one of the researchers at Florida Gulf Coast University, told Wired, “We don’t have any results to report yet." The procedure sounds easy enough. The trapped mosquitoes are smashed, then examined for traces of Zika. It will just be a matter of waiting for results and getting a large enough sample of local potential carriers.

According to the Associated Press, the location of this infection, Miami-Dade County, has the most confirmed cases in Florida. But, of the 89 cases they have all been traced to travel to Latin or South America or the Caribbean. Health officials have been predicting local transmission to come to the continental United States this summer as mosquito populations grew. It may be that that has finally happened.

Given the seriousness of the effects of the Zika virus, especially for pregnant women, President Barak Obama has been keeping abreast of the spread of hte virus. According to a White House press release, Obama spoke with Florida Governor Rick Scott about this development. He reconfirmed his promise to send more funding to the state to combat the spread of Zika in the coming weeks.

This is not the first news of the Zika coming to the United States this week. ABC News reported on a bizarre case of the disease where the contraction appeared to occur neither by a mosquito (here or abroad) nor through sexual intercourse. Someone had been caring for a Zika-infected relative when they began showing symptoms.

Clearly, there is still so much researchers don't know about the virus. Without a clear picture, it's difficult to combat it. As of now, there is not vaccine for Zika, and the main strategy for prevention is staving off mosquito bites.