LOS ANGELES, CA — More mosquitoes tested positive for West Nile virus over the past week in various Los Angeles County locations, including seven areas that had their first positive tests of the year.

According to the Greater Los Angeles County Vector Control District, West Nile virus activity was detected for the first time this year in Artesia, East Los Angeles, El Sereno, Elysian Valley, Hawaiian Gardens, Newhall and Signal Hill. Vector-control officials warned that the current heat wave could contribute to a spread of the virus.

"This week's high temperatures are going to increase the risk of West Nile virus infections for many residents," said Levy Sun, public information officer for the district. "The first line of defense against mosquitoes is to remove all standing water. It's a simple solution, but it is also easy to forget." Residents who have ongoing problems with mosquitoes were asked to contact the district at (562) 944-9656 or at www.ReportMosquitoes.org.

So far this year, West Nile virus has been detected in 169 mosquito samples in the district's service area, and in 41 dead birds and five sentinel chickens. One human case of the virus has been confirmed in Los Angeles County.

Symptoms of West Nile may never materialize, but can include fever, headache, nausea, body aches, skin rashes and swollen lymph nodes.

Mosquitoes typically become carriers of the virus after feeding on an infected bird and can then spread the potentially lethal strain to animals and humans.