Zika's now spreading from state to state in the U.S.. Health officials in Texas said Monday a resident there caught Zika in Florida and brought it home.
It doesn't mean Zika's an epidemic just yet, but it does show just how easily the virus can spread once enough people in an area are infected.
"This is the first Texas case to be linked to travel within the continental United States. The case will be classified as 'travel-associated' and is being investigated for more details," the Texas health department said in a statement.
"Health officials linked this case to Miami travel after closely evaluating travel dates, symptom onset date and known local transmission of Zika virus in Miami."
Miami has a small local cluster of Zika cases, which rose to 30 Monday with two more reported patients.
But with limited money and people for testing, it's hard to know for sure. Federal and state officials have had to shift money from other work to take on Zika, in part because Congress is on a break without having allocated any cash.
Florida has allocated $18 million to flight Zika.
"There are two new non-travel related cases today in Miami-Dade County," the Florida health department said in a statement.
"One of the individuals was exposed in the less than one-square mile in Miami-Dade County. The second new non-travel related infection is located outside of the one-square mile area in Miami-Dade County."
To spread, Zika needs infected people. The virus circulates in blood, semen and can also be found in saliva and urine. The yellow fever mosquito -- Aedes aegypti -- is the main culprit, but the virus can also be spread sexually.
"There have been no reported cases of Zika virus disease transmitted by mosquitoes in Texas, but Texas is on alert for the possibility of local transmission," the Texas health department said. "State efforts have been underway since January to delay and minimize the impact of Zika on Texas."
Texas also has Aedes aegypti mosquitoes.
Most people aren't at big risk, but infection can cause severe birth defects if a pregnant woman gets infected.
Florida officials say they are investigating the new case that is not in the Wynwood neighborhood just north of downtown Miami. It's the third local case from outside the neighborhood where officials know mosquitoes are spreading the virus.
"Mosquito abatement and reduction activities will take place around the area of interest," they said. "The department still believes active transmissions are still only occurring in the area that is less than one square mile in Miami-Dade County."
Overall, Florida has more than 450 known Zika cases, 440 of them in travelers. But because Zika causes no symptoms in most people, experts agree there are likely far more.
Florida's at special risk because it's home to the Aedes mosquitoes that spread the virus. So an infected person can be bitten without even knowing they are spreading the virus. The more travelers with Zika, the more likely a mosquito will bite one of them and then bite someone else.
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Florida says it can test 5,544 people for active Zika virus and 3,141 for Zika antibodies -- evidence someone was infected in the past.
"Per the governor's direction on August 3, all county health departments are now offering free Zika risk assessment and testing to any pregnant woman who would like to be tested."
Florida says 59 residents who have Zika are pregnant.
So far, the investigations of the cases outside Wynwood have not found anyone else infected other than the known cases, which indicates the virus is not actively spreading in those places, the health department said.
"One case does not mean active transmission is taking place, and that's why the department conducts a thorough investigation by sampling close contacts and community members around each case to determine if additional people are infected," the department said.
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"The department has not yet determined where the individual in Palm Beach County or the three individuals outside the one-square mile in Miami-Dade County likely contracted Zika and will share more details as the investigations progress. If the department finds evidence that active transmission is occurring in an area, we will notify the media and the public."
The Centers for Disease Control and Prevention warns women who are pregnant or thinking of becoming pregnant to stay away from areas where Zika is spreading.
"Florida's small case cluster is not considered widespread transmission, however, pregnant women are advised to avoid non-essential travel to the impacted area in Miami-Dade County," the department said.
"The department urges Floridians to drain standing water weekly, no matter how seemingly small. A couple drops of water in a bottle cap can be a breeding location for mosquitoes."
The CDC also recommends covering up with long pants and long sleeves and the use of insect repellents.