Mosquitoes in DeKalb and Fulton counties have tested positive for West Nile virus. Health officials warn that standing water from recent rains could create breeding grounds for infected insects. Residents across the state report increased mosquito activity in recent weeks. People should avoid being outside during dusk and dawn when mosquitoes are most active during the summer. Residents should get rid of any containers holding standing water around their homes, including buckets, barrels, flowerpots or tarps.