The Connecticut Agricultural Experiment Station,123 Huntington St.-Box 1106, New Haven, CT 06504

(203) 974-8485, Web site: http://www.state.ct.us/caes

As blood feeders, ticks can be a nuisance; their bites can cause irritation and, in the case of some ticks, paralysis. Ticks also can transmit several human and animal disease pathogens. In Connecticut, the two most common ticks are the blacklegged tick, Ixodes scapularis (formerly known as the deer tick, I. dammini) and the American dog tick, Dermacentor variabilis. 'Me prevention of tick bites and the prompt detection and removal of attached ticks can reduce the chances of infection. Additional information is available from the Experiment Station fact sheets on Tick‑Associated Diseases, Ticks, Tick Control, and the American Dog Tick.

The pathogens that cause Lyme disease, human babesiosis, and human granulocytic ehrlichiosis (HGE) are spread by the bite of Ixodes scapularis. The American dog tick transmits the agents of Rocky Mountain spotted fever and tularemia, and can cause tick paralysis.

The blacklegged tick has three active stages; the larva, nymph, and adult (male and female). Each stage feeds only once and slowly: requiring several days to ingest the blood. All active stages will feed on people and pets.

By contrast, only the adult stage of the American dog tick feeds on people and pets. Adult ticks are active from April through August.

Most Lyme disease cases are associated with the bite of the nymphal stage of I. scapularis. Although an average of only 20% of the nymphs in Connecticut are infected with B. burgdorferi, this can vary from about 10‑30% in any given year. Nymphs are small (about the size of a pinhead), difficult to spot, and are active during the late spring and summer months when most people are outdoors (see above). Adults of I. scapularis are more heavily infected with B. burgdorferi (30‑60%) than the nymphs, but are associated with fewer cases of Lyme disease. Adult ticks are larger, easier to spot, and are active in the fall, warmer days in the winter, and in the spring when outdoor activity is limited.

Dress appropriately and check for ticks . . .

Ticks do not jump, fly or drop from trees, but grasp passing hosts from the leaf litter, tips of grass, etc. Most ticks are probably picked up on the lower legs and then crawl up the body seeking a place to feed. Wear light‑colored clothing with the pants tucked into socks. Repellents can substantially increase the level of protection. On returning home, remove and wash the clothing. Carefully inspect the body and quickly remove any attached ticks. Tick bites are usually painless and, consequently, many people may be unaware that they have been bitten. Also, carefully inspect children and pets. Ticks may attach anywhere on the body. Pets can bring ticks into the home, resulting in a tick bite without the person being outdoors. Many tick bites are thought to occur around the home. Ticks may not be infected, and studies have indicated that it may require 36‑48 hours or more for transmission to occur from an attached nymph. Therefore, a tick bite does not necessarily mean a person will develop Lyme disease.

Remove ticks promptly...

Prompt removal of an attached tick will reduce the chance of Lyme disease infection. Use thin‑tipped tweezers or forceps to grasp the tick as close to the skin surface as possible. Pull the tick straight upward with steady even pressure. This should remove the tick with the mouthparts intact. If the mouthparts break off, it will not affect the chance of getting Lyme disease. Disinfect the area; a topical antibiotic may also be applied. A dead tick can be saved in alcohol. If a tick is to be tested for spirochetes, place it in a small vial or jar with a blade of grass to keep it alive. Note the site and date of the bite. Other methods of tick removal (e.g. petroleum jelly to suffocate the tick) are not effective. Use of heat from matches to make the tick back out or gasoline or other chemicals are unacceptable. Watch for signs and symptoms of Lyme disease.

Repellents...

DEET: The primary active ingredient in most insect/tick repellents today is DEET (N,N‑diethyl‑3‑methylbenzamide or N,N‑diethyl‑m‑toluamide). DEET is the most effective, broad‑spectrum repellent ever discovered. The U.S. Environmental Protection Agency (EPA) estimates that over one‑third of the U.S. population will use a DEET‑based product. There are approximately 230 products containing DEET registered with the EPA (e.g. Cutter, Off, Repel, Muskol, Ben's Sawyer, and others). Products range in concentration from 4% to 100% DEET and are available as an aerosol can, pump spray bottle, stick, lotion, cream, or towelette for application to skin or clothing. DEET is only effective for one to several hours and must be reapplied periodically. The effectiveness of DEET on the skin is influenced by the concentration of DEET, absorption through the skin, evaporation, sweating, air temperature, wind, and abrasion of the treated surface by rubbing or washing. Higher concentrations generally provide longer protection, but increasing the concentration does not provide a proportional increase in protection time. Recently, several controlled‑release DEET formulations have been developed which decrease skin absorption and increase protection time. Extended duration products include HourGuard, Skedaddle, and Sawyer's Controlled Release. All active ingredients and their concentrations are listed on the product label.

DEET and ticks: DEET will repel ticks and decrease the chances of tick bite, but depending upon the concentration, it may not provide total protection against I. scapularis. Little is known about the effectiveness of different concentrations of DEET against I scapularis. Concentrations of DEET that might prevent tick attachment may not deter a tick from walking across the skin to unexposed and untreated areas. When applied to clothes, 30% and 20% DEET was found to be 92% and 86% effective against I. scapularis, respectively, but skin applications were reported to be only 75 to 87% effective against crawling ticks in a second study. For blacklegged ticks, DEET concentrations around 30 to 40% probably should be used, although the effectiveness of higher (>50%) and lower (<20%) concentrations against I. scapularis needs to be examined more closely. When applying a repellent against ticks, particular attention should be given to the shoe tops, socks, and lower portion of pants.

Permethrin: Several products contain 0.5% permethrin (e.g. Duranon Tick Repellent, Repel Permanone, Cutter Outdoorsman Gear‑Guard, Permethrin Tick Repellent), which is for use only on clothing or other fabrics ‑such as mosquito netting or tents. A synthetic pyrethroid insecticide rather than a true repellent, permethrin works primarily by killing ticks on contact with the clothes and can provide high levels of protection against tick bites (and mosquitoes). Permethrin is available as a 0.5% aerosol spray, mainly in lawn and garden centers or sports stores. Permethrin has low mammalian toxicity, is poorly absorbed through the skin and is rapidly inactivated by' the body. Skin reactions have been uncommon.

"Natural" or Herbal" Repellents and other products: Several products containing citronella oil (0. 1 to 15%) are marketed for protection against mosquitoes but are probably less effective against ticks. Avon markets a citronefla‑based (0.05%‑ product with sunscreen under the Skin‑So‑Soft label for protection against mosquitoes and ticks. Applications of plant-derived repellents that might reduce tick attachment are less likely to deter a tick from walking across the skin to an untreated area. Avon's bath oil, Skin‑So‑Soft has been widely used as mosquito repellent and will protect against mosquito bites for up to 30 minutes, but it is unlikely to be effective against ticks.

Safe Use of DEET. The EPA has recently completed a review of DEET as part of evaluating pesticides for reregistration. The EPA believes that normal use of DEET does not present a health concern to the general population and has detailed that decision in a Reregistration Decision document (available from the EPA). All uses and formulations of DEET (except those combining DEET and sunscreen) can be reregistered if the products meet EPA's new labeling requirements for directions, precautions, and claims. For example, child safe claims for low concentration DEET products will no longer be allowed. The EPA is requiring changes to the label to ensure the safe use of DEET, particularly on children.

DEET has been used by millions of Americans for 40 years and the incidence of adverse reactions is low. However, a few allergic, toxic and neurological reactions to DEET have been reported in the medical literature. DEET is readily absorbed into the bloodstream. Therefore, it is prudent to minimize the use of high concentrations on the skin. Apply sparingly to exposed skin, and spray on clothing when possible. Follow the precautions given on the repellent label. Consumer Reports suggest 40% DEET or less for adults; 20% or less for children. The American Academy of Pediatrics recommends 10% or less DEET in repellents used on children. DEET will harm some synthetic fabrics, plastics, car and furniture finishes, etc. lf you suspect a reaction to DEET (or any other repellent), stop using the product, wash the treated skin, and call the poison control center (CT 1‑800‑343‑2722). Medical and safety information about the active ingredients in an insect repellent is available from:

National Pesticide Telecommunications Network (NPTN) by telephone (1‑800‑858‑7378) from 6:30 a.m. to 4:30 p.m. Pacific Standard Time or 9:30 a.m. to 7:30 p.m. Eastern Standard Time.

Mention of a repellent product does not constitute an endorsement by the CT Agricultural Experiment Station