Pests Frequently Asked Questions

A vector is an animal, insect, or arthropod that can transmit diseases to humans, or cause a public health nuisance.  Examples include mosquitoes that can transmit West Nile Virus, fleas that can transmit Plague, and deer mice that can transmit Hantavirus.

These assessments provide mosquito and other vector-borne disease control and surveillance services throughout San Diego County.  The Vector Control Program provides the public with early detection of public health threats, mosquito control, property inspection, onsite advice, public education, and information on controlling vectors.  

A tick is not an insect, but instead is more closely related to a spider. It is a small ectoparasite, meaning it remains on the outside of its host while taking a meal. Ticks feed on the blood of mammals, birds and reptiles. You may not realize that you have been bitten by a tick for several days because you can hardly feel the bite. Once bitten, ticks can stay attached to you for several weeks if you do not remove them.

San Diego County is home to several species of ticks, but only 4 of them bite humans. These four are the: Western black-legged tick, the American Dog tick, Pacific Coast tick and the Brown Dog Tick.  

People usually get tick bites by brushing up against vegetation while outdoors. Ticks tend to wait at the end of blades of grass or leaves of low-lying vegetation for a suitable host to brush by. Ticks do not leap, jump, or fly, so by avoiding touching brush and low-level plants while outdoors, you can greatly reduce your chance of getting them.

Ticks like warm, dark places. They most often bite on the back of the knee, underneath your waistband, in your armpit, on the back of your neck or on your scalp, or around your ears. It may take several hours for a tick to bite you once it is on you. Ticks usually climb on you at some point below your knees, where you brushed against a plant. They then search for a suitable place to bite.  If a tick has bit you, it will be embedded in your skin and hard to pull out.  

Use a pair of tweezers to remove the tick. Grasp the tick firmly as close to your skin as possible, and gently but firmly pull the tick straight out.

• Do NOT scrape the tick off.
• Do NOT twist the tick.
• Do NOT grab the tick by the body and pull.
• Do NOT try to burn the tick.
• Do NOT try to “suffocate” the tick with petroleum jelly or other products.

You may want to save the tick to have it identified later if you become ill. Just place it in a small container like a film canister. [kill it first by placing it in rubbing alcohol.] To have a tick identified, call the Vector Control Program at 858-694-2888. 

• Avoid brush and low lying vegetation when outdoors.
• Wear a tick repellent.
• Wear light colored clothes (to make spotting ticks easier)
• Tuck your pant cuffs into your socks, and your shirt into your pants.
• Check frequently for ticks on your skin and clothes when outdoors. Have a friend check your back.
• When you return home, be sure to do a thorough check of your clothes and skin for ticks. 

Lyme disease is caused by a bacteria that is carried by some (not all) ticks, most often the Western black-legged tick. If you notice a red rash around the bite that resembles a “bulls eye” that appears 1-2 weeks after you were bitten, this might be a sign of Lyme disease. Not all people who are infected with Lyme disease get this rash. Other symptoms of Lyme disease include: fever, headache, fatigue, muscle aches, and swollen lymph nodes. If you see a rash or feel sick after being bitten by a tick, go see your doctor.

The best known disease that ticks can transmit to humans is Lyme disease. Ticks can also carry: Tularemia, ehrlichiosis, Rocky Mountain spotted fever, tick-borne relapsing fever, and typhus.

Unless kept as a house pet, rats are destructive pests that can cause structural damage to your house, spread disease, and contaminate food. They can even cause house fires by chewing on electrical wires.

Rats transmit diseases such as the plague, food-poisoning, rat-bite fever, and parasitic diseases such as tapeworm.  Rats are also able to carry rat mites.  

Check for the most common signs of rat activity.
• Rat droppings
• Signs of gnawing
• Stripped bark on trees
• Scratching or scurrying sounds coming from the walls
• Dark-colored, greasy stains on walls caused by rubbing of their fur
• Damaged food containers and food
• Piles of cut snail shells under plants in the garden
• Sometimes you will notice a sweet, musty smell caused by the urine of rats

Visit the Vector Control Program's Rat website for more information.  

If you think you have a rat problem, you can call the Vector Control Program (858-694-2888). The Vector Control Program (VCP) offers FREE on-site rat inspections of your property and a FREE Rat Control Starter kit. The VCP is not a pest control agency and will not get rid of the rats for you, but will assess your property and advise you on the best ways to control the problem yourself. In some cases, you or your property manager may need to seek additional assistance from a pest control company.

In San Diego County, the roof rat is the species which lives in our residential areas.  They can be found under piles of wood and debris, in garages, attics, and storage areas.  Keep wood piles, lumber and household items neatly stacked at least 18 inches above the ground and away from walls and fences.  Clean up and haul away trash and debris.  Trim trees, bushes, and vines at least four feet away from your roof.  

Rats cannot live without food, water, and shelter. If you deny them one or all of these, they are less likely to stay on your property. For more simple steps on how you can rodent-proof your home click here.

There are 24 different types of mosquitoes in San Diego County. They all need standing water to complete their life cycle. You can protect yourself from mosquito bites and the diseases these insects carry (West Nile Virus, encephalitis and malaria) by eliminating water sources on your property. Keep roof gutters and drainage ditches clean, change bird baths and animal troughs weekly, store boats upside down or cover them tightly, and store tires in a covered area. If you have ornamental pools, stock them with mosquito-eating fish which are available from the Vector Control Program. Call (858) 694-2888 for more information.

Be wary of the Black Widow and Brown Widow spiders in San Diego County.  To learn more about spiders please visit the Vector Control Program's Spider website.    

Although their sting may be painful, none of the species of scorpions found in San Diego County are considered lethal.  You should still consider seeking medical attention for a sting.