CONCORD (BCN) – Local scientists discovered mosquitoes in Antioch and a dead bird in Oakley that tested positive for the West Nile virus, the Contra Costa Mosquito and Vector Control District announced Tuesday.

The district trapped and tested a group of about 50 mosquitoes, and the bugs found near Lone Tree Way and Dear Valley Road mark the first group of mosquitoes to test positive for West Nile in Antioch this year. The American crow was found near Fetzer and Jordan lanes in Oakley.

Technicians will continue to conduct surveillance and carry out inspections and treatments in the area to suppress the mosquito population. “There are mosquitoes that have tested positive and people need to take precautions,” district spokeswoman Deborah Bass said.

According to Bass, mosquitoes often thrive in man-made sources, including street drains, ornamental ponds, gutters, horse troughs, neglected swimming pools and flowerpot saucers. “It only takes about a tablespoon of water to breed mosquitoes,” Bass said, adding that one neglected pool could lead to more than 1 million mosquitoes that can fly as far as 5 miles.

Residents are urged to reduce lawn overwatering, car washing and any other activities that can provide mosquitoes with a place to breed. If extreme cases of mosquitoes are found, residents should contact the Contra Costa Mosquito and Vector Control District at (925) 771-6195.

People infected with the West Nile virus may experience flu-like symptoms, including fever and headaches, Bass said. To report any dead birds, call to 877-WNV-BIRD (877-968-2473) or visit www.westnile.ca.gov.