New study results from the Centers for Disease Control and Prevention (CDC) show that mosquitoes that can spread Zika, dengue and chikungunya viruses are in more counties in the southern United States than was previously known. According to the results, 38 more counties reported documenting A. aegypti mosquitoes between 1995 and 2016, an increase of 21 percent over last year’s total.

After a Zika outbreak in Florida last summer, researchers from the CDC expanded mosquito-collection measures across the South. The CDC said the findings “highlight the need for continued and improved mosquito surveillance.”

A. aegypti was reported in all southern U.S. states, with most county reports coming from California, Arizona, Texas, Louisiana and Florida. A. aegypti is generally known to thrive in tropical and subtropical counties.

The findings underscore the importance of work the NACDS Foundation has done, in response to a call from the CDC and the CDC Foundation last year, to assist in efforts to prevent the spread of the virus among populations most likely at-risk. An awareness campaign was launched in Puerto Rico in 2016 and was expanded to include a media interview tour in Texas, Louisiana and Florida, where the mosquitos that carry the disease are more prevalent.

In May, Morning Consult published an op-ed penned by NACDS Foundation President Kathleen Jaeger, which described NACDS Foundation’s efforts work with stakeholders—the March of Dimes Foundation and the University of Rhode Island College of Pharmacy—on efforts to protect at-risk populations.