The number of confirmed West Nile virus cases in the Santa Clarita Valley this summer now stands at 12, according to data from the Greater Los Angeles County Vector Control District.

All cases involve dead birds. No mosquito samples in the SCV have been separately identified so far.

Birds, usually crows, contract the virus when they’re bitten by infected mosquitoes. The cycle continues when mosquitoes are infected by biting a bird that carries the virus.

This past week, West Nile virus showed up for the first time this summer in Chatsworth, Los Feliz, Montebello, Panorama City, Reseda, Sherman Oaks, Van Nuys and Woodland Hills.

[See all cities/reporting areas with confirmed West Nile virus]

“Mosquitoes and West Nile virus go hand-in-hand with the hot weather we’re experiencing,” said Levy Sun, the district’s public information officer. “We can expect more virus activity as the summer progresses.”

Vector control recommends that residents eliminate all standing water sources from properties, and report mosquito problems and inoperable swimming pools and ponds to the district promptly.

Residents experiencing mosquito problems during the day or at night, even after dumping all standing water, can receive help from the Greater Los Angeles County Vector Control District at (562) 944-9656 or visit www.ReportMosquitoes.org.