That mosquito, known as Culex, thrives in underground storm sewers in the height of summer and mostly comes out in the evening.

But the Aedes mosquito that carries the Zika virus is more common and often bites during the day, Duhrkopf said. And the patterns of contagion are quite different, he said.

“To some extent, West Nile virus is something we know how to deal with,” Duhrkopf said. “This is different enough from West Nile virus that we’re going to have a learning curve.”

Whereas the Culex mosquito transmits West Nile virus to humans from migrating bird populations, Aedes mosquitoes appear to spread Zika from person to person. But scientists don’t yet know whether Zika will spread as fast in the U.S. as it has in parts of Latin America, such as Brazil.

“Given the way in which it seems to spread through South America, it seems to be quite contagious,” Duhrkopf said. “That may be because of conditions unique to South America, where there are large cities with very dense populations.”

In Central Texas, the dominant Aedes mosquito is A. albopictus, or the Asian tiger mosquito, notable for the white stripes on its body. Sim said the tiger mosquito arrived in the 1980s in a shipment of old tires from Asia and has now become widespread.