In collaboration with Cary Institute of Ecosystems, Dutchess County published "Science-based Responses to Commonly Asked Questions About Tick-Borne Disease Prevention." Based on extensive literature review of published scientific studies, this publication provides a wealth of information on avoiding ticks, protective clothing, tick repellents, tick removal, and tick checks. Those who are interested in more detailed explanation of findings can access the fully-referenced literature reviews:
Lyme disease is by far the most frequently diagnosed tick-borne disease in Dutchess County. Anaplasmosis and babesiosis also occur commonly. Ehrlichiosis, Powassan Virus encephalitis, Rocky Mountain spotted fever, and tularemia are diagnosed infrequently. Borrelia miyamotoi is a newly recognized pathogen. Levels of this disease in the population are not yet known.
A: In order to reduce the risk of getting a tick-borne disease, the CDC recommends the following:
The questions and answers that follow look at the science behind these and other personal protection recommendations. Protection measures are grouped into the following categories: avoiding ticks, protective clothing, tick repellents, and tick checks and tick removal.
More information on the effectiveness of prevention measures can be found in our Protection Measure Overview document.
Most cases of Lyme disease and other tick-borne diseases happen in the late spring and early summer when juvenile ticks called nymphs are active and out in high numbers. Nymphs are thought to be responsible for the majority of cases due to their small size which makes them difficult to find and remove quickly.
Adult ticks can also transmit disease, but do so less frequently than nymphs because they are large enough to be noticed and removed before disease transmission takes place. Adult tick numbers peak in the spring, and again in the fall. They can survive through the winter months, so exposure is possible year-round, but uncommon with snow cover and below freezing temperatures.
Heightened vigilance and closest attention to tick bite prevention is warranted during the warmer months of the year when risk is greatest. Disease rates peak in June and July, with rates lowest from December through March.
A: Forests contain the highest numbers of ticks. When comparing forests, deciduous (broad leaf) forests with shrubs covering the ground contain more ticks than coniferous (evergreen) forests or wetlands. Small wooded areas, like those often found between houses in neighborhoods, tend to contain more ticks than large continuous forests.
Within forests, the most ticks are found in areas with three or more inches of ground cover, and the fewest are found in areas where bare earth is visible.
Nymphs (juvenile ticks) are found most commonly in leaf litter or on low growing plants near ground level. Adult ticks may be found in the leaf litter or in brush or shrubs less than three feet high.
In the northeastern United States, it is common for people to be bitten by ticks on their own property. On residential properties, ticks are found in greatest abundance in wooded areas, followed by unmaintained edges between lawns and wooded areas, gardens, and lawns. Lawns next to wooded areas have more ticks than lawns that do not border wooded areas. Properties in densely populated villages present less risk for tick bites than properties in areas with lower population densities.
For more information about tick habitats, please see our Tick Bite Avoidance document.
Common sense dictates that activities taking place in places with the most ticks (the woods) presents a greater risk for contracting a tick-borne disease. Within wooded areas, time spent on the ground or sitting on logs presents even greater risk for acquiring a tick compared to walking.
Evidence for consistently risky activities has been difficult to document scientifically, probably due to the great variability in places used for work and play. Some studies, but not all, found hunting, clearing brush, extended periods spent gardening, attending children’s sporting activities, and picnicking outside of designated areas in parks to be risk factors for tick-borne disease.
For more information about activities and risk of tick-borne disease, please see our Tick Bite Avoidance document.
Walking in the center of trails is a common recommendation to decrease the likelihood of being bitten by ticks. To our knowledge, no scientific studies have been done to put this recommendation to the test. Based on existing evidence, if bare ground is visible in the center of trails, then it is possible that walking in the center may be beneficial.
For more information about avoiding risk factors for tick-borne disease, please see our Tick Bite Avoidance document.
Clothing can be used to block ticks from contacting the skin. Common recommendations include:
Some studies have found people who consistently follow these recommendations are at a decreased risk for getting a tick-borne disease, but other studies have not.
For more information about these studies, please see our Clothing document.
To our knowledge, no scientific studies have examined the specific practice of tucking pants into socks. Surveys have found the majority of people are unwilling to tuck their pants into their socks. In general, many people don’t wear the recommended protective clothing because they are concerned about appearance, or find it uncomfortable to wear in warm weather.
For more information about protective clothing, please see our Clothing document.
Since ticks are usually found close to the ground, it stands to reason that wearing shoes provides important protection from ticks. There is some evidence to show that boots offer the most protection from tick bites.
One study in the northeastern United States found more ticks on people when they wore sneakers as compared to when they wore hiking boots. However, a study in California (please note, differences exist between ticks in California and ticks in the northeastern United States) found no differences in the number of ticks crawling on people when they wore boots, sneakers, or sandals.
For more information about these studies, please see our Clothing document.
The most effective products to repel and kill ticks on clothing contain permethrin. Permethrin is designed for use on clothing and outdoor gear, not skin. It has consistently been found to work better and last longer on clothing than repellents containing DEET that are commonly used on skin.
Permethrin dip or spray applied to clothing is effective for two weeks and through several washings. Commercially made permethrin impregnated clothing (Insect Shield®) available through retailers like LL Bean and Orvis stays effective through at least seventy washes. A 93% decrease in the incidence of tick bites was seen in a study of outdoor workers wearing permethrin impregnated clothing as compared to those wearing untreated clothing.
Safety Note: Always follow repellant label directions carefully. Do NOT apply permethrin directly to the skin. Allow treated clothing to dry completely before wearing, as directed by the label on the permethrin product.
For more information about permethrin, please see our Repellents document.
The highest degree of protection is achieved when the least possible skin is exposed, and all outer layers of clothing contain permethrin.
Since surveys have shown that people are unwilling to wear long pants and long sleeves in warmer months, studies have been conducted to examine the level of protection provided by treating more typical summer clothing. Treating shorts, t-shirts, sneakers, and socks with permethrin has been shown to make tick bites more than three times less likely to occur. The biggest “bang for your buck” can be obtained from wearing permethrin treated shoes and socks. Treating shoes and socks has been shown to decrease tick bites by 74%.
For more information about permethrin, please see our Repellents document.
The most effective way to kill ticks that may be alive and crawling on clothes or gear is to put them in an automatic dryer, set on hot, for one hour. Washing machines are not effective at killing ticks, even on hot settings with detergent added.
For more information, please see our Tick Check document.
Like all of the protective measures suggested, repellents can help decrease tick exposure, but they do not provide 100% protection from tick bites. Some, but not all, surveys have found that people who use insect repellents run less risk of getting tick-borne diseases. Tick repellents can only be expected to work if they are used consistently (every time you are in a place where you might get a tick), if you choose a product that has been proven to do what it says it can do on the label, and if you follow the directions on the label.
More information about specific repellents can be found in the remaining questions in this section and in our Repellents document.
Scientific studies comparing repellents don’t provide a clear answer to the question of what repellent is most effective on skin, but they do give us a list of products likely to work well. The CDC recommends using products that contain 20-30% DEET on exposed skin, but DEET is not the only active ingredient that is effective when applied to skin. Repellents containing the following active ingredients also have been shown to be effective in scientific studies: IR3535, 2-Undecanone, Picaridin, and p-Menthane-3,8-diol (PMD).
Product formulation also affects how well a repellent works. In general, products that contain the active ingredients in higher concentrations tend to be more effective than those with active ingredients in lower concentrations. Products that are oil- or polymer-based tend to last longer than water- or alcohol-based products.
There is no way to know how well a product works if it hasn’t undergone testing for safety and effectiveness. Repellents registered by the Environmental Protection Agency (EPA) have to undergo testing to show that they can do what their labels say they can do. If a product is not registered by the EPA, it has not had to meet this standard. Registered products will have an EPA registration number displayed on their label. Some, but not all, EPA registered products will also display a new EPA graphic showing what insects are repelled and for how long.
For more information on the effectiveness of repellents, please see our Repellents document.
or the greatest assurance that a product will be effective, we recommend you choose one of the many EPA-registered repellents on the market. The EPA provides a useful online tool to help consumers choose which repellent best meets their needs, Users can search for products based on what they want to repel (ticks, mosquitoes, or both), and how long they need it to be effective. The tool produces a list of registered products that meet the search criteria, providing product name, duration of action, active ingredient, and percent active ingredient.
To learn more about the science behind the many different active ingredients and types of repellents on the market, please see our Repellents document.
DEET is the most common active ingredient in repellents on the market, and has been in use for more than fifty years. Due to this long history, there is a large body of evidence supporting its effectiveness. Twenty percent (20%) DEET is commonly used as the standard for comparison for other repellents. Products with higher DEET concentrations tend to be more effective and last longer. Some formulations, such as the product LIPODEET, are able to produce extended durations of activity with lower DEET concentrations. Over the years there have been occasional reports of DEET toxicity, but a recent review of safety data did not find a link between use of DEET and severe adverse events. With all insect repellents, it is important to follow label directions to reduce risk of potential side effects.
For more information about DEET, please see our Repellents document.
The Centers for Disease Control and Prevention recommend the use of products containing the active ingredients picaridin or IR3535 for people looking for an alternative to DEET. Products containing these ingredients have performed well in studies comparing them to products containing DEET. One study found IR3535 to be more repellent to black-legged tick nymphs (which are common in our area) than a similar concentration of DEET. The active ingredient 2-undecanone has also been found to be as repellent to ticks as DEET in some laboratory studies.
For more science on tick repellents, please see our Repellents document.
It is important to remember that “natural” is not necessarily the same thing as safe. It is true that some natural ingredients may be safer to use than man-made ingredients and may have the environmental advantage of being biodegradable. However, some natural ingredients are toxic, some are skin irritants, and some contain carcinogens.
The EPA considers many natural ingredients, often derived from essential oils of plants, to be "minimum risk pesticides," meaning they pose minimal health risk. Products containing "minimum risk pesticides" are not required to be registered by the EPA. Non-EPA registered products are not required to undergo testing for effectiveness. Testing that has been completed shows the effectiveness of essential oil-derived pesticides is often limited by their tendency to evaporate. This can be overcome with higher concentrations, but higher concentrations tend to cause skin irritation. Plant-derived pesticides are an active area of scientific research.
In order to choose a safe and effective repellent, we recommend you choose an EPA-registered product. Some EPA-registered tick repellents do contain plant-derived active ingredients, such as oil of lemon eucalyptus, 2-undecanone (made from wild tomato plants), and p-Menthane-3,8-diol (made from leaves of the Australian lemon-scented gum tree). Other EPA registered active ingredients like permethrin and IR3535 are man-made copies of plant derived chemicals.
For more information on repellents, please see our Repellents document.
The most effective products to repel and kill ticks on clothing contain permethrin. Permethrin is designed for use on clothing and outdoor gear, not skin. It has consistently been found to work better and last longer on clothing than repellents containing DEET.
For more information about permethrin, refer to the Protective Clothing section (Section III) of this web resource or our Repellents document.
The CDC recommends the following:
Most surveys show that tick checks result in some reduction in the risk of getting a tick-borne disease. The rationale for frequent tick checks is that, in general, transmission rates of tick-borne disease increase with duration of tick attachment. In other words, even if you are bitten by a tick carrying a disease, you are less likely to get that disease if you remove the tick in a short amount of time.
More information on the risk reduction provided by frequent tick checks can be found in our Tick Check document.
Tick checks should be done as soon as possible after leaving the places where ticks are most commonly found (woodlands and the borders between woods and other environments). In places like Dutchess County where ticks and tick-borne disease are very common, it’s easy to come into contact with ticks without even realizing you’ve been in a risky environment. Especially during the warmer months of the year when most tick bites occur, it is a good idea to do a tick check at least once every 24 hours. Most people find tick checks are easier to remember if they are made part of the daily routine, for instance, each night after taking a shower.
In general, the sooner a tick is safely removed the less likely it is to transmit disease. This is because most tick-borne diseases have a “grace period,” or period of tick attachment prior to disease transmission. Research has shown there is a grace period of about 36 hours for Lyme disease. Duration of grace periods is not as well defined for other agents. Research suggests that anaplasmosis and babesiosis are unlikely to be transmitted if ticks are attached less than 24 hours. In contrast, there does not appear to be any grace period prior to transmission of Powassan virus.
More information on grace periods can be found in our Tick Check document.
The CDC recommends the following:
A video of proper tick removal technique can be found at the New York State Department of Heath website.
Avoid folklore remedies such as "painting" the tick with nail polish or petroleum jelly, rotating the tick with a wet Q-tip, or using heat to make the tick detach from the skin. Your goal is to remove the tick as quickly as possible--not waiting for it to detach.
The basis for these recommendations are scientific studies showing that “passive” removal methods (techniques meant to encourage ticks to detach without pulling) don’t work, and increase risk of disease transmission. Using a hot match poses the additional risk of causing burns to the skin. Scientific studies have not found one type of tool or technique (pulling straight vs twisting) for pulling out ticks to be consistently more effective than others. There is a lot of variability in terms of the species and size of tick you are attempting to remove. Fine tipped tweezers, a common item in most houses, used in the manner described above, are a reasonable choice for tick removal. For more information on tick removal methods, please see our Tick Check document.
Ticks may be disposed of in a sealed container, such as a plastic zipper closure bag, and placed into the trash. It has been suggested that rather than simply disposing of ticks, additional testing may be beneficial in determining the risk of disease transmission.Testing may consist of tick identification and estimation of attachment time, or testing for specific disease agents.
Some labs offer testing for specific disease-causing agents in ticks. Such testing is not generally considered useful because it is unlikely to alter decision making about treatment. Such tests do not indicate if the disease(s) have been transmitted to the patient. False negatives are also common with these tests, so they may in fact provide a false sense of reassurance.
Tick species identification and measurements of engorgement may provide information useful in assessing the risk of disease transmission, and deciding if prophylaxis (medication intended to prevent disease) for Lyme disease is warranted. Prophylaxis should be given within 72 hours of tick removal. If a physician thinks prophylaxis is warranted, it should be given immediately rather than waiting for tick testing results for specific disease agents.
For more information on tick testing, please visit our Tick Check document.