Due to positive testing of West Nile Virus in local mosquitoes, Santa Clara Vector Control, an organization that monitors and controls disease-carrying and harmful pests in the Santa Clara County, fogged the Sunnyvale-Cupertino area on Oct. 23.

Fogging, according to Santa Clara Vector Control’s website is a process in which a pesticide is released into an area in a microscopic mist or “fog”, in this case from truck-mounted fogging machines in the hours of 11 p.m. to 2 a.m.

The pesticide used is Zenivex E4, containing active ingredient Etofenprox, a common agricultural pesticide used in Ultra Low Volume (ULV), in this case 1.5 fluid ounces (three tablespoons) over an acre.

A representative of Santa Clara Vector Control said that the pesticide should have no side effects on humans.

A few De Anza students are concerned, however.

Kevin Chen, Biology Major, says that he concerned about the effectiveness of the mosquito fogging and whether repeated use could contaminate the groundwater.

According to the website, the pesticide should be safe for pets since there are higher doses of Etofenprox on flea and tick control for cats and dogs, but recommends that any toys and dishes left outside should be washed or wiped down.

Mia Hernandez, the chair of the environmental sustainability committee of the DASB said she was also concerned about the fog contaminating the environment, especially in regards to marine life.

Vector Control representative also said that the county decides to fog an area if there are mosquitoes positive for West Nile Virus and if the post-fogging mosquitoes test positive again, then Vector Control reschedules another fogging.

According to the Centers for Disease Control (CDC) website, West Nile Virus does not develop symptoms in most people (70-80 percent), but about 20 percent of people infected suffer from fever and “headache, body aches, joint pains, vomiting, diarrhea, or rash”.

Less than one percent of people infected develop a neurological illness like encephalitis or meningitis.

Currently, there is no cure or vaccine for the West Nile Virus.