Though American's fear over the local Zika virus transmission has all but disappeared since last fall, health officials say the threat will return as temperatures rise in the coming months.
The Zika virus is transmitted through the bite of an Aedes mosquito, which thrives in tropical and subtropical climates.
Infected mosquitoes are predominantly spread across Latin America and the Caribbean; however, the warm summertime air of the southern U.S. allows them to move northward.
To date, 48 countries and territories in the Americas have confirmed vector-borne transmission of the Zika virus since 2015, according to the Pan American Health Organization.
And, the threat isn’t over.
"Although Zika may seem like last year's problem, or an issue confined to Brazil, there have been more than 1,600 cases in pregnant women reported here in the U.S.," Anne Schuchat, acting director of the Centers for Disease Control and Prevention (CDC), told NPR in early April.
“We're still seeing about 30 to 40 Zika cases in pregnant women each week in the U.S. Zika is here to stay,” she said.
Climate change has also sparked fears that the virus could spread farther.
“In terms of the impact of climate change, there are certainly concerns that the territories that are hospitable to some insect vectors may be changing as well,” Daniel Caplivski, MD, an associate professor of Infectious Diseases at Icahn School of Medicine at Mount Sinai, said.
Zika has been found to cause serious birth defects, including microcephaly, which results in babies born with abnormally small heads and incomplete brain development.
Despite its devastating complications, officials have yet to find a way to eradicate the virus or halt its transmission.
“There are no major breakthroughs in terms of an antiviral,” Caplivski said. “Similarly, we have been fighting other flaviviruses like dengue and yellow fever for decades, and there is still no antiviral therapy available.”
Numerous vaccine trials are underway to combat the infection, however, health officials say it will likely be many years until any are approved for use.
According to the CDC, a total of 1,297 pregnancies with possible recent Zika virus infection were reported to the U.S. Zika Pregnancy Registry in 2016.
Approximately one in 10 pregnancies with laboratory-confirmed Zika virus infection resulted in a fetus or infant with Zika virus–associated birth defects.