Top health officials from the Centers for Disease Control and Prevention have expressed a heightened concern about the threat the Zika virus poses to the United States.

According to USA Today, Dr. Anne Schuchat, the principal deputy director of the CDC, told reporters during a White House press briefing, “Most of what we’ve learned is not reassuring, everything we look at with this virus seems to be a bit scarier than we initially thought.”

“And so while we absolutely hope we don’t see widespread local transmission in the continental U.S., we need the states to be ready for that,” Schuchat added.

Zika is a mosquito-borne illness that causes premature birth, blindness, and small brain size caused by microcephaly in babies. Mothers exposed to the Zika virus while pregnant are the most at risk, so they need extra medical attention throughout the entire pregnancy. 

So far there have been 346 cases of the Zika virus in the United States, most being travelers returning from currently affected areas.

The CDC is pushing for federal funding to stop this virus in its track before the human toll gets too high. The White House said that it will redirect $589 million, mostly from money already provided by Congress to tackle the Ebola virus, to prepare for Zika before it begins to emerge in the United States as the weather warms.

As summer approaches, the CDC warns that mosquito eradication efforts, lab tests and vaccine research may not be able to catch up. The Zika-carrying mosquito, Aedes aegypti, could be more widespread than originally thought, having the potential to travel as far north as San Francisco and New York.

New research finds that Zika can also be transmitted sexually, which is causing the CDC to update its suggestions.

Zika has the potential to affect any existing drugs in a patient’s immune system; meanwhile, more than half of Americans have used a prescription drug within the last 30 days. Those who are taking prescription drugs and are diagnosed with the Zika virus should speak to a doctor to ensure their medicines do not impact the virus.

Brazil, one of the countries most at risk, has confirmed more than 1,046 cases of microcephaly and considers most to be related to Zika infections in the mothers. With the upcoming Olympic Games in Rio this summer, the CDC recommends pregnant women avoid traveling to the country.