The Zika threat appears to be worsening, with news Friday of the first cases of people contracting the disease in the continental United States.

Four individuals in Miami have reportedly been infected with Zika while in the U.S., according to the Centers for Disease Control and Prevention. Until last week, there had been more than 1,600 confirmed cases of Zika in the states, but all had been tied to travel abroad.

Across the country, health care professionals have been prepping for a possible escalation of the Zika outbreak, but many say they’ve been hampered by a lack of resources, with Congress leaving for its recess without approving $1.9 billion in funding President Barack Obama is asking for to combat the threat. Following Friday’s news, health care stakeholders such as the American Medical Association turned up the volume on their pleas for further help.

“Today’s news that it is highly likely that cases of mosquito-transmitted Zika virus exist in the continental United States is no surprise,” AMA President Andrew Gurman, M.D., said in a statement. “This should be a wake-up call to Congress and the administration that they must resolve their differences and immediately make the necessary resources available for our country to combat the growing threat of the virus.

“Congress and the administration must act as quickly as possible to ensure that our country is able to deploy the kind of public health response necessary to keep our citizens safe and healthy.”

In its own statement issued Friday, the CDC said it is working closely with Florida officials on the matter and has provided the state with more than $8 million in Zika-specific dollars to aid in the fight. The center urges people, especially pregnant women, to protect themselves from mosquito bites by wearing long sleeves and pants and using insect repellent.

If you haven’t been following our previous coverage, Zika is a virus that’s spread primarily through mosquito bites as well as during sex with an infected person. Most of those who are infected don’t show symptoms, according to the CDC, but infection during pregnancy may cause serious defects in infants.

The American Hospital Association has compiled a handy list of resources on the Zika virus if you’d like to learn more. Hospitals & Health Networks' Matt O’Connor, also spoke with a CDC official earlier this week on steps hospitals can take to address the outbreak.