The Sacramento-Yolo Mosquito and Vector Control District received preliminary confirmation Monday that four mosquito samples, three from Wilton and one from Carmichael, have tested positive for West Nile virus.

In response to the West Nile virus mosquito samples, the District will continue to implement its Mosquito-Borne Disease Management plan to protect public health and welfare, which involves the use of fogging machines.

This plan includes ground treatments where virus activity has been detected.

Vector control said all products are registered with the California Environmental Protection Agency (EPA) and are applied by trained and state-certified technicians.

The District said it will use its e-mail notification list to notify individuals about the fogging locations and schedule. However, the District may not be able to notify the public if immediate applications are needed to protect public health and welfare from serious diseases such as West Nile virus. The District may also cancel a scheduled operation due to weather and/or other reasons without prior notice.

The District routinely collects and tests adult mosquitoes throughout Sacramento and Yolo counties.

"This is similar to what we saw last year. People need to be aware of just how fast West Nile virus can amplify now that we are in the summer months," said District Manager David Brown.