The San Joaquin County Mosquito and Vector Control District will begin spraying for mosquitoes tonight after the earliest detection of the West Nile virus in nine years.

On Friday, the District reported that two infected samples were collected at traps along Division Road and the Manteca-Ripon city border near Caswell Memorial State Park.

It was the earliest detection of the West Nile virus in the county since its discovery in 2004, and it came less than a week after a Manteca couple suffered thousands of bites after being stranded along the Stanislaus River.

Six counties have reported West Nile virus activity, including Yuba, Sacramento, Fresno, Tulare and Los Angeles. Only Sacramento has reported a human case, while the others have found the virus in dead birds and mosquitoes.

In response to the local detection of the West Nile virus – found in adult mosquitoes – the District will begin ground spraying operations tonight and Friday morning in select areas in rural Manteca and Ripon.

Spraying will take place tonight 8:30-11 o’clock, and on Friday from 4-7 a.m. Areas of focus are:

• South rural Manteca: North to Division Road; south to San Joaquin/Stanislaus River; east to Stanislaus River; west to Two Rivers Road.

• Southwest rural Manteca: North to West Ripon Road; south the East Moncure Road; east to Mohler Road; west to Frederick Road.

• Ripon sewer-Ripon: North to Doak Road; south to Stanislaus County line; east to Stockton Avenue; west to Robert Avenue.

The West Nile virus has posed a threat to public health since 2004. In 2003, there were three documented human cases and no fatalities.

Since then, there have been 3,625 human cases with 130 fatalities. In 2012 alone, there were 479 human cases and 20 deaths – the most since 2007 (21), according to California West Nile Virus.

In the San Joaquin County, there were 13 human cases (no fatalities), two diseased horses, 59 dead birds and 169 infected mosquito samples in 2012.

The West Nile virus can cause West Nile fever (headaches, muscle pain, fatigue, nausea and vomiting) in human cases, and in severe instances, neurological disease.

People of older or younger age, as well as those with pre-existing medical conditions are most susceptible.

For more information or to file a service call, contact the San Joaquin County Mosquito and Vector Control District at (209) 982-4675 or visit them online at www.sjmosquito.org.

To report dead birds and tree squirrels to (877) WNV-BIRD or www.westnile.ca.gov.