Contra Costa Mosquito and Vector Control District — How Can We Help You?

With Contra Costa County’s weather warming up, it’s finally feeling like spring. And with the nice weather, Contra Costa County residents are heading out, and on occasion have found an insect or other animal for which they need some help. This is when residents turn to the Contra Costa Mosquito and Vector Control District (District). Our response is, “How can we help you?”

The District is a public health agency dedicated to protecting the community from mosquitoes and other vectors of disease. District employees provide specific services for specific insects and other animals.

Here’s a handy list of the insects and other animals for which the District provides service followed by details on each service.

• Mosquitoes: The District provides inspection and control of mosquitoes, including placement of mosquitofish when appropriate to prevent mosquitoes in residential water features.
• Rats and Mice: The District provides inspection and advice for rats and mice.
• Skunks: The District provides inspection and assistance for skunks.
• Ticks: The District provides a tick identification service for Contra Costa County residents.
• Ground-nesting yellowjackets: The District provides inspection and treatment of ground-nesting yellowjackets nests specifically.
• Bees: The District provides limited inspection and education services for honey bees.

For more detailed information on these District services, continue reading.

• Mosquitoes: The District provides inspection and control of mosquitoes, including placement of mosquitofish when appropriate to prevent mosquitoes from developing in residential water features including decorative ponds and neglected swimming pools.

During the District’s mosquito service, a District employee will visit the residential property and will inspect the front and back yards for signs of mosquito development. If there is a water feature, such as a decorative pond or a no-longer-in-use swimming pool or hot tub, the District employee will inspect the water feature for possible mosquito activity, and determine the appropriate course of action which may include placing mosquitofish in the water feature to prevent future mosquito activity. The District employee will also provide the resident with recommendations on what to do to reduce the risk of mosquitoes on private property.

If the resident has a chance to swat one or more of the mosquitoes that are present on the property and place the dead mosquitoes in a clear plastic bag, the mosquitoes in the bag may provide helpful information to the District employee.

Rats and Mice: The District provides inspection and advice for rats and mice.

While providing this service, a District employee will visit the residential property, and inspect the property for evidence of a rat or mouse such as rub marks, droppings, or nesting material. The District employee will provide advice about specific things that can be done to reduce the risk of rats or mice on the property as well as written materials with additional information on rat and mouse prevention.

• Skunks: The District’s skunk program is technically a rabies risk reduction program because skunks are high on the list of animals that test positive for rabies in California. And the risk of rabies transmission increases when skunks establish a den in close proximity to Contra Costa County residents.

The District’s skunk service consists of a District employee inspecting the residential property for signs of a skunk den. If there is evidence of a skunk den or signs of a skunk accessing the property, the District employee will provide assistance by showing the resident where and what prevention efforts should be taken on the property. The District employee will also provide written information on skunk prevention and may provide specific notes regarding the property.

• Ticks: The District provides a tick identification service for Contra Costa County residents.

There are four species of ticks that commonly bite people in Contra Costa County, but only the Western black-legged tick is known to transmit the causative agent of Lyme disease.

To receive the District’s tick identification service, after a Contra Costa County resident removes a tick from a person or pet, the resident must place the tick in a clear plastic Ziploc-style bag or sealed clear container, and place the bag or container into an envelope, along with the resident’s contact information. Then, send the tick to the District or drop it off at the District office. The District’s laboratory staff will identify the submitted tick and respond to the resident using the contact information provided, usually within two business days. If the tick is a Western black-legged tick, and the resident wants to have it tested for the causative agent of Lyme disease, the District will return the tick and provide a list of laboratories that can test the tick for the causative agents of Lyme disease; however, the California Department of Public Health (CDPH) does not recommend tick testing. For more information, CDPH provides this set of questions and answers regarding tick testing.

Ground-nesting yellowjackets: The District provides inspection and treatment of ground-nesting yellowjacket nests specifically.

Ground-nesting yellowjackets are a type of wasp that can

build nests in abandoned rodent burrows, in between railroad ties, and in other voids underground. Because they are underground, Contra Costa County residents may not know these wasps are present; however, when a resident steps on a nest, mows over the nest, or bumps into the nest while gardening, the yellowjackets will emerge to protect their nest. Ground-nesting yellowjackets can sting and bite repeatedly, which is painful for an unsuspecting resident, but for those who are allergic to wasp venom, the bites and stings can be dangerous. This is why the District provides ground-nesting yellowjacket service.

Contra Costa County residents can request the District’s ground-nesting yellowjacket service after first finding the nest, placing a garden tool, old shoe, or other visible items near the nest, and then leaving a basic map of the area where the nest is located taped to a side gate or front door. Be sure to indicate on the map what item was used to mark the nest location. The District employee who responds to the request for service will use the map and items left to mark the nest to locate the nest. Once the District employee locates the nest and confirms it is ground-nesting yellowjackets, the District employee will treat the nest and leave the resident with instructions on how to approach the nest post-treatment.

• Bees: The District provides limited inspection and education services for honey bees. The District does not respond to bee-stinging incidents. In the case of a stinging incident that requires emergency services, please call 911 for assistance. The District treats bee swarms or hives that are a threat to people in public areas such as a school or shopping center. The District does not treat bee hives that are in or on a structure or on private property.

For bee swarm collection and removal, the District refers Contra Costa County residents to the Mount Diablo Beekeeper’s Association or residents may contact a colony removal specialist or a private pest control company.