Mosquitoes are being trapped and frozen at Fort Benning and other posts as part of the military‘s effort to combat the Zika virus that has infected at least 11 service members among more than 1,000 Americans.

Army Pvt. 1st Class Mary Pendris at Benning in Georgia near the Alabama line is among those troops on mosquito trapping duty to detect the presence of the Aedes aegypti mosquitoes whose bites can spread the virus which can cause birth defects, including microcephaly, according to the Centers for Disease Control.

Once the mosquitoes are trapped at Benning, they are frozen and shipped to the Environmental Health Department of Preventative Medicine on the Georgia post, and then sent to the Army’s Public Health Command-Atlantic at Fort Meade in Maryland for testing.

“We haven’t found any, at least not yet,” of the Aedes aeqypti mosquitoes at Benning, although they are known to be present in the southeast, said Maj. Scott Robinson, chief of preventive medicine at Benning’s Martin Army Community Hospital.

Dr. Robinson said that Benning and other Army posts have also been screening troops who have recently returned from South America and the Caribbean, where the Zika virus has hit hardest.

He said that no cases of Zika have turned up yet among Benning troops but two cases of related infections also spread by the Aedes aegypti mosquito – dengue fever and Chikungunya virus – have been found.

Chikingunya can lead to fever lasting two to seven days and possible long-term joint pain. The symptoms of dengue are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding from the nose and gums, according to the CDC.

Robinson said his only recourse if Aedes aegypti mosquitoes were found at Benning would be to summon post pest control to spray the area where they were trapped and restate already standing Army guidelines on prevention, including using approved repellents, wearing long-sleeved shirts and staying when possible in air conditioned areas.