(BCN) -- The Alameda County Mosquito Abatement District has found four additional Aedes aegypti mosquitoes in Pleasanton after announcing last week the discovery of the non-native insect that hadn't been seen in the county for a decade and is capable of spreading diseases. The district placed traps in areas south of the Amador Valley neighborhood of Pleasanton and found mosquitoes inside and near the Alameda County Fairgrounds and neighborhoods northeast of the fairgrounds. An Aedes aegypti mosquito was previously discovered last week in an area west of Amador Valley High School and east of Hopyard Road, the first time since 2014 that the species was detected in Alameda County. The Aedes aegypti mosquito can spread diseases like dengue, Zika and yellow fever, according to the district. Exotic bird stolen from East Bay shop found, returned over 1 month later Mosquito district staff are going to all properties in the area to inspect for mosquitoes, which lay their eggs near water, and estimated they have inspected about a quarter of the properties in the initial detection area. "The Alameda County Mosquito Abatement District appreciates the help of residents who allowed inspections on their property," district general manager Ryan Clausnitzer said in a statement Tuesday. "Staff have been in the area conducting inspections over the weekend, and will continue to inspect properties over the next few weeks." Staff members doing the inspections will be in uniforms with a logo on their shirts and will have additional identification if requested. The district said it is also working with fairgrounds staff to enhance monitoring and treatment for mosquitoes at that site. Aedes aegypti is present in 19 counties throughout the state, including neighboring Contra Costa and Santa Clara counties. More information on the district and its programs can be found on its website at https://www.mosquitoes.org. Copyright © 2024 Bay City News, Inc.