The combination of warm weather and possible increased tourism arrival makes Zika virus more likely to hit the United States by summer.
The Centers for Disease Control and Prevention (CDC) has confirmed 182 Zika virus infections among the 4,534 people screened from Jan. 3 to March 5. All of these cases are travel associated, and so far, there's no reported local transmission, which means the virus-borne mosquitoes may not be in the country yet.
However, that may be about to change as the weather warms and summer rolls in. The Aedes aegypti, the same species that spreads dengue and chikungunya viruses and the one that feeds on humans, and Aedes albopictus mosquitoes are fond of warm weather. The rising temperatures will allow the virus to stay in the gut for a longer period and increase their appetite.
Further, inbound tourism arrival is particularly high during this season. In June 2015 alone, the number of international tourists including those from Canada and Mexico rose by around 4 percent from 2014, according to Department of Commerce.
Although it's unclear where the virus may begin local transmission, simulation models believe it will be highly concentrated around Florida all the way to North Carolina, New York, and some parts of Texas.
Zika caused by A. aegypti may be found in more urban areas since the species have already become more resilient, being able to breed even on bottle caps with stagnant water. Meanwhile, local transmission caused by A. albopictus may occur in the outdoors, especially in places where there are tree holes and natural water sources.
As a preparation for more frequent Zika virus infection, the CDC has already instructed "health care providers offer testing to asymptomatic pregnant women with possible exposure to Zika virus," said the report. This is even if the women do not present any symptoms such as rash, conjunctivitis, and fever.
It may also be necessary to change the traditional methods of eliminating the mosquitoes including insecticide spraying, which some environmental groups have frowned upon since it may also kill the mosquitoes' natural predators.
Although some states have not ruled out insecticides, "there are products that have a softer footprint out there, products that are kinder to all of us and the environment, and we should use those," said a St. Louis, Missouri, mosquito control spokesman Dave McLaughlin.
The CDC has since issued an interim recommendation on how to control mosquitoes, but it suggests that preparation should happen early. President Barack Obama has also redirected $589 million to fight the virus.