Andrew Ross (left) and Rylie Smith use dip cups to check a small body of water for mosquito larvae near Hermiston in 2019.

The West Umatilla Mosquito Control District is conducting its annual targeted aerial mosquito control spraying, including spraying that took place the weekend of Aug. 9 over 5,000 acres north and east of Hermiston.

According to the news release, mosquito control operations are designed to decrease the spread of West Nile virus that some mosquitoes carry.

While the virus mostly affects birds, mosquitoes can also pass it on to humans or horses when they bite.

The risks of the virus are low and most infected people do not become ill or develop mild flu-like symptoms, but in rare cases West Nile virus may cause dangerous swelling in the brain, known as encephalitis.

The district recommends seeking medical attention for unusual, severe headaches.

Things people can do to help reduce mosquito populations are to get rid of opportunities for standing water on their property, such as old tires or clogged gutters, and flush ornamental ponds, horse troughs and other needed water sources regularly.

People should also protect themselves from mosquito bites by wearing long-sleeved shirts and pants outdoors, using mosquito repellent and maintaining screens on windows and screen doors.

Area residents can report mosquito infestations and dead bird sightings to the West Umatilla Mosquito Control District at 541-567-5201.