Engorged tick embedded in your skin? Before you toss it away, get it identified.
The bite from a lone star tick nymph produced an itchy red rash that lasted more than a week.
This week a family member presented me with an immature tick (nymph) recently removed from the underside of his arm. A quick microscopic examination revealed the tick was engorged, meaning it had fed long enough to possibly transmit a tick-borne illness such as the Borrelia bacterium which causes Lyme disease. Fortunately, with the help of the microscope and some excellent tick identification information from the Québec National Institute of Public Health (Institut national de santé publique du Québec), even a Bug Guy could inform his kin that a nasty case of Lyme disease was not in his future. And how does one figure this out? Well, here comes TMI. On the underside of a tick, the anus is clearly visible (yes, they also have one). Near the anus, a morphological structure called the anal grove is present. Blacklegged ticks have an anal grove that looks like an up-side-down horseshoe enclosing the anus from above. Other species of ticks, ones that don’t carry Lyme disease, have an anal grove that looks like a right-side-up horseshoe enclosing the anus from below. Conclusion – if the horseshoe is up-side-down your luck has run out. If the horseshoe is right-side-up, your luck hasn’t run out and you won’t be getting Lyme disease. You may contract another tick-borne illness, but not Lyme disease. By the way, Lyme disease is the most common arthropod-borne illness in the US and the incidence of Lyme disease in the US is roughly three times greater than the incidence of ehrlichiosis, another tick-borne illness.
Could this blood-engorged tick carry Lyme disease bacteria? By flipping the tick on its back morphological structures can be seen. The dark brown circle in the center is the anus (yes, ticks have these too). A faint, right-side-up horseshoe or cup-shaped line called the anal suture below the anus indicates that this is not a blacklegged tick. Concerns about contracting Lyme disease from this tick can be put to rest. That’s good news.
In previous episodes we met blacklegged ticks, the vector of Lyme disease. We also learned about red-meat allergies and ehrlichiosis and the lone star ticks responsible for these afflictions. The message this week is short and to the point. If you discover a tick that has embedded in your skin (in contrast to one still roaming around) do not simply pluck it off and toss it out. A better move is to determine its identity and discover what disease organisms it might harbor. There are several tick-testing services that will identify the tick and perform molecular analysis to determine several important disease agents it may be carrying. Tick identification is available through the University of Maryland, but this service does not test for disease agents. On a recent encounter with a tick, after removing a lone star tick from my waist, I sent it off to a tick-testing laboratory. Within a week, I had results and this little rascal tested negative for the causal agents of Lyme disease, relapsing fever, anaplasmosis, Rocky Mountain spotted fever, Pacific Coast tick fever, tularemia, and ehrlichiosis. Lucky me. If your report comes back and tests are positive for one or more tick borne diseases, consult your physician and develop an action plan. Several tick-testing services can be found on the internet by simply googling “Tick Testing Services”. They provide step by step directions to prepare your sample for analysis and where to send it.
Panel B of this diagram shows how to separate blacklegged ticks and their kin, vectors of Lyme disease, from other ticks that do not carry Lyme disease. The upper tick is Ixodes which include blacklegged ticks, and the lower tick could be one of many others that do not transmit Lyme disease, but do transmit other diseases. To see a complete diagram useful in tick identification, please click on this link: https://www.inspq.qc.ca/en/it-tick Credit: Québec National Institute of Public Health.
Just as a reminder, to reduce the risks of becoming a meal for a tick and the unfortunate recipient of alpha-gal, STARI, ehrlichiosis, or other tick-borne illnesses including Lyme disease, remember the word “AIR”. This stands for avoid, inspect, and remove.
“A” - Avoid ticks and their bites in the following ways. When taking Fido for a walk, stick to the path, trail, or pavement. You are unlikely to encounter ticks on non-grassy surfaces. If you enter habitats where wildlife and ticks are likely to be present, such as grassy meadows, borders of fields and woodlands, and vegetation along the banks of streams, wear long pants and light-colored clothing. This will help you spot ticks on your clothes as they move up your body. Be a geek - tuck your pant legs into your socks. Pants tucked into socks forces ticks to move up and over your clothes rather than under them where tasty skin awaits. Apply repellents labeled for use in repelling ticks. Some are applied directly to skin, but others can be applied only to clothing. Don’t forget to treat your footwear, socks, and pant legs. Immature ticks, the rascally and hard to detect nymphs, are a key vector of diseases and these precautions will help prevent nymphs and adults from attaching to your skin. If repellents are used, be sure to read the label, follow directions carefully, and heed precautions particularly those related to children. If your adventures take you into tick territory, consider placing your cloths directly into a clothes dryer rather than a hamper upon returning home. The heat of the dryer will kill hitchhiking ticks that might otherwise escape clothes in the hamper and cause trouble after your return home.
“I” - Inspect yourself, your family, and your pets thoroughly if you have been in tick habitats. Remember to do this when you return from the outdoors and when taking a shower. A thorough inspection may involve enlisting a helper to view those "hard to see" areas around back.
“R” - Remove ticks promptly if you find them. Removal within the first 24 hours can greatly decrease your risk of contracting a disease. If you find a tick attached, firmly grasp the tick as close to your skin as possible using a pair of fine forceps and slowly, steadily pull the tick out. Cleanse the area with antiseptic. The CDC and the Bug-Guy do not recommend methods of tick removal such as smearing the tick with petroleum jelly or scorching its rear end with a match. Cases of some tick-borne diseases such as Lyme disease are the most common in children and seniors, so take special care to keep kids of all ages safe when they play outdoors.
Acknowledgements
Bug of the Week thanks Brian for sharing his tick, which served as the inspiration for this episode. To learn more about tick identification and diseases ticks carry, please visit the wonderful resources provided by Québec National Institute of Public Health and the CDC Tick ID website.