SIMI VALLEY (CBSLA) – A horse in Simi Valley has tested positive for West Nile Virus.

The Ventura County Environmental Health Division reports that the horse tested positive for West Nile on Tuesday. It was the first horse to test positive for the virus in Ventura County in three years.

READ MORE: Dozens Of Calif. Colleges To Pay Students $10K For Public Service Work Under New State Program

It’s the tenth horse so far this year in California to test positive for West Nile, according to the state Department of Food and Agriculture. At least seven of the horses were unvaccinated. Three of them died and the other seven are still alive and/or recovering.

The condition of the Simi Valley horse was not disclosed.

READ MORE: LA Musician Marty Roberts Of ‘Marty & Elayne’ Lounge Band Dies At 89

West Nile is primarily transmitted through the bite of an infected mosquito in the Culex genus.The Southland has seen more mosquito activity than usual this summer thanks in part to the record rainfall the region received this past winter.

Several neighborhoods in Orange and Los Angeles counties have been sprayed with pesticides to combat the mosquito populations there. To help curb their spread, residents are advised to remove or actively replace any standing water in and around their homes.

For more information on West Nile in horses, click here.

MORE NEWS: Suspect ID'd As Shawn Laval Smith In Murder Of Brianna Kupfer, Hancock Park Furniture Store Employee Found Stabbed