INDIO, Calif. -

Four human cases of West Nile virus have been reported in Riverside and San Bernardino counties.  None are in the Coachella Valley.

Yet that doesn't mean the threat posed by mosquitoes and West Nile is over for Valley residents.

The Coachella Valley Mosquito and Vector Control District reports 106 mosquito samples have tested positive for West Nile this year.  20 more than the previous record.

"We did increase the amount of surveillance we've done since that time,
so we have been collecting more mosquitoes, said Greg White, a vector ecologist with Mosquito and Vector Control.  "There is a combination of probably more collections being done, but also there just more virus this year.

Beginning Monday and for five consecutive nights, Mosquito and Vector control is scheduled to spray for mosquitoes in the Mecca area and in Indio around the Valley Sanitary District marshlands.  The spraying is scheduled for between 7 p.m. and 9 p.m. in Indio and between 8:30 p.m. and 10:30 p.m. in Mecca.

The humid weather the Valley has experienced this summer has allowed mosquitoes to thrive.