Aedes aegypti mosquitoes were discovered again in Jackson County -- one year after the Oregon Health Authority and the county announced the species had been found for the first time in the state.
OHA, Jackson County Vector Control and Jackson County Public Health have confirmed the presence of the rare mosquitoes as part of a routine surveillance program.
OHA officials said the repeat appearance of the Aedes aegyptic mosquitoes is a concern because the species has been more common in the warmer climates of the United States, Southeast Asia, Africa and the Pacific Islands. They have been known to carry and transmit diseases that are more typical to warmer climates such as Zika virus, dengue and yellow fever.
The mosquitoes become infected when they bite and feed on someone who is infected with the virus. They primarily feed in the daytime and prefer to feed on humans. However, health officials emphasize that the risk of these infections to local residents is low.
Aedes aegypti cannot fly far -- only about 500 feet. These mosquitoes prefer warm and wet weather, and to live in or near homes or in neighboring woods. Officials said changes in climate are allowing them to expand their range to the western US.
Routine surveillance monitors different mosquito populations in Jackson County and tests for diseases such as West Nile Virus and Western Equine Encephalitis that are common to the Culex mosquito genus. It also gives Jackson County Vector Control the ability to determine human risk and implement strategies to control these insects and prevent disease spread.
