AMES, Iowa (AP) — Iowa State University insect experts say an extensive surveillance project last year found that the two mosquito species most associated with Zika virus are not established in the state.

The ISU Medical Entomology Laboratory oversaw mosquito trapping in 15 Iowa counties. The traps collected nearly 176,000 mosquitoes between May 3 and Oct. 4. Not a single specimen of the two species known to transmit Zika was found.

Ryan Smith, an assistant professor of entomology, says not a single specimen of the two species known to transmit Zika was found.

He says the research is intended to try to answer questions about whether they'll get here and if so, when.

Zika carrying mosquitoes are in Missouri and Illinois and surveillance will be heightened in southern and eastern Iowa counties.