There are 53 species of mosquitoes reported in California. Of the 22 species of mosquito that exist in the West Valley area, some are vectors of disease causing organisms of humans and domestic animals, and others are nuisances. In the West Valley area we are concerned with three (3) major mosquito-borne diseases; St. Louis encephalitis (SLE), western equine encephalomyelitis (WEE), and West Nile virus (WNV). In order to monitor these diseases we have implemented a mosquito-borne disease surveillance program to monitor the presence of SLE, WEE and WNV.

We use caged chickens as sentinels in selected locations within the District boundaries to monitor the presence of mosquito-borne viruses. A small blood sample is taken periodically from each chicken and tested for the presence of antibodies specific to SLE, WEE and WNV. If antibodies are found, this indicates that the chicken has recently been exposed to the encephalitis virus.

As part of the surveillance efforts, we also use carbon dioxide (CO2) baited traps and oviposition (gravid) traps to monitor mosquito populations. The trapped mosquitoes also are used for testing of the presence of SLE, WEE and WNV viruses.

In addition, the West Valley Mosquito and Vector Control District maintains a record system of complaints, surveys, inspections, and control activities.

RODENTS:

There are a number of rodent species in Southern California capable of harboring or transmitting diseases. Of those diseases, we are primarily concerned with Hantavirus, Arenavirus and Plague. We have implemented a program to monitor rodent-borne diseases and rodent populations.

We trap for rodents and sample their blood and then test it for the presence of antibodies to Hantavirus, Arenavirus or plague. This accomplishes two things, we are aware of what rodents species is predominate in the area at any given time, and we are also aware of the diseases that the rodents are likely to carry.

In addition, the West Valley Mosquito and Vector Control District maintains a record system of complaints, surveys, inspections and control activities.