The Truth about Chiggers and Ticks
Kevin A. Shufran, Ph.D.
As an entomologist, I am aware of much misunderstanding the public has concerning insects and their relatives. This is especially true for two creatures which are the bane of hunters and all outdoor enthusiasts; chiggers and ticks. Hopefully this will clear things up a bit and help keep you and your loved ones safe from these pests when afield.
Chiggers and ticks are not insects. They are arachnids, which are close cousins of insects and include spiders, scorpions, and mites. In fact, chiggers are mites. A chigger is the larval stage of a mite in the family Trombiculidae. Nymphs and adults of chiggers are called harvest mites which are free living and predators of small arthropods and their eggs. Your head may be spinning from the scientific jargon, so it’s important that I review some terms and basic biology.
What are arthropods? This is a group of invertebrates, or animals without backbones, and includes insects, spiders, scorpions, daddy long legs, crustaceans, centipedes and millipedes. While your boss may not have a back bone, he is not an invertebrate by scientific standards. Arthropod literally means “jointed foot”. A key feature of all these animals is they have external skeletons or hardened skins. To grow they must periodically shed their skins. This is called molting and marks the changes between their various life stages. The basic life stages of mites and ticks are: 1) egg; 2) larva; 3) nymph (several molts); and 4) adult. That is enough basic bug biology for now and is probably more than you wanted to know.
In Oklahoma, if you have ever been outdoors walking across the lawn, you have encountered chiggers. Most of us can recall our first discovery of chiggers as youths, and mine was a particularly horrible event. We know we have gotten chiggers by the red welts on our legs, ankles, groins, and waists that itch badly and can last for days or even weeks. Again, the chigger is the larval stage of a mite and is microscopic in size. They occur in grass, weeds, and woods during the warm months of spring, summer and early fall, but may be active even during winter in warmer states or years. Look at the picture of the chigger and you will notice it has 6 legs. We are taught early in school that only insects have 6 legs, but here is an exception. After the chigger molts into a nymph it will then have the normal set of 8 legs we associate with arachnids (mites, ticks and spiders).
Chigger (From CDC)
Contrary to a popular belief, chiggers do not burrow under your skin. Chiggers feed by inserting their mouth parts into your skin at a pore or hair follicle and inject their saliva. The saliva dissolves your skin cells which the chiggers then ingest. Itching occurs within 3 to 6 hours followed by the familiar red welts. The welts continue to develop and the itching becomes severe over the next 2 to 3 days. After a few days the chiggers will drop off and then molt into the nymph stage, at which point they become predators of small arthropods and their eggs. Meanwhile you continue to itch madly. Despite the terrible itching and ugly red welts, chiggers are not dangerous to humans in the US. However, in Asia they can transmit diseases such as scrub typhus. In Burma during WWII, more casualties were attributed to chiggers and scrub typhus than the enemy.
A warm, soapy shower will wash away the chiggers from your skin. If you can do this within a few hours of encountering chiggers, the symptoms can be greatly reduced. If you wait too long to bathe, your chigger bites will continue to develop even though the chigger is no longer feeding on you. I think this is where the myth may come from about their ability to burrow under your skin. For most cases, over the counter products like calamine lotion and hydrocortisone creams can alleviate the itching. A person with a severe case (like me at age 14) should seek medical attention. If you get chiggers, do not wear the same clothes, socks or shoes again without washing them. Otherwise you’ll just re-infest yourself (like me at age 14).
There is a running joke that Oklahoma is the tick capitol of the US. I think this has merit as ticks are active year round and Oklahoma State University maintains an impressive tick research program. Ticks go through a similar life cycle as chigger mites, except ticks are parasites during every life stage from larva to adult. Like chiggers, larval ticks (AKA “seed ticks”) also have 6 legs, but nymphs and adults have 8 legs. Larval ticks are nearly microscopic and most people bitten by them do not know it. Larval ticks are about the same size as the period at the end of this sentence. Ticks feed on blood. All species and sexes of ticks require a blood meal. This is unlike mosquitoes and other flies in which only females feed on blood. After becoming engorged (at which point they look like a grape), ticks drop off their hosts to molt, mate, or lay eggs. Afterwards, they will seek out another host. We attract ticks by our movement, body heat, and the carbon dioxide and lactic acid our bodies give off. A difference between chiggers and ticks is ticks will attach and feed without us feeling anything. This is an important point because of their role in transmitting disease causing agents, which will be discussed below.
There are two kinds of ticks; hard ticks (family Ixodidae) and soft ticks (family Argasidae). We are most familiar with hard ticks because these are the kind that attach to humans, dogs, cats, deer, and other mammals. Soft ticks prefer to feed on birds and reptiles, but one species (spinose ear tick) likes to feed in the ears of cattle, horses, wild animals and sometimes even humans. The most common hard ticks we are likely to encounter in Oklahoma are the lone star tick, black-legged tick (sometimes called a deer tick), American dog tick, brown dog tick, and winter tick.
Top: female black-legged tick (deer tick).
Middle: female lone star tick.
Bottom: ticks engorged with blood.
(From The University of Nebraska)
Ticks are a concern because they can transmit disease causing microorganisms (bacteria, spirochetes, rickettsias, and viruses). The two most common tick transmitted diseases in Oklahoma are Rocky Mountain spotted fever and ehrlichiosis. Reported cases of these two diseases to the Oklahoma Department of Health have increased since 1998. Tularemia and Lyme disease also are possible however, Lyme disease is very rare in Oklahoma. Other tick-related diseases that are present in Oklahoma are encephalitis, relapsing fever, and tick paralysis. All are serious diseases and humans need prompt medical attention at the first onset of symptoms, or if you become sick after having being bit by a tick. Because of the different animal hosts ticks utilize, as well as their physiology, not all tick species will or can transmit all disease causing germs. Only a portion of ticks in the wild harbor the germs, so the probability of a single tick bite leading to disease is relatively low. In other words, don’t panic if you or your children are bitten by a tick. Ticks can only transmit the disease if they feed on you, or if they are smashed and their body fluids are rubbed into a wound. Click Here to see a chart of common tick transmitted diseases.
If you are bitten by a tick and remove it, preserve the tick by putting it in a small jar of rubbing alcohol (even spirits can do in a pinch). Knowing the species of tick will help doctors to properly diagnose which disease you might have should you become sick. Remember that seed ticks usually go unnoticed, and many people diagnosed with tick related diseases do not recall being bitten. I am not going to go into the symptoms of each disease and which tick transmits them, however you should seek medical attention if you develop any of these symptoms.
- High fever.
- Flue-like symptoms (fever, chills, head and body aches, tiredness).
- A rash around the bite, especially if it appears like a bulls-eye.
- A rash occurring on other parts of the body.
- Sleeplessness, restlessness, or delirium.
- Loss of appetite, nausea, or vomiting.
- Pain in joints, muscles, or eyes
- Swollen and tender lymph nodes.
- Paralysis of hands and feet.
- Itching or swelling around the bite.
Everyone should carefully check for ticks during and after being outdoors. Be sure to check everywhere, including the groin and back of the head. If possible, get help from another person doing this. Parents, check your children thoroughly. Investigate anything suspicious looking. Small ticks can look just like moles or birth marks. If you find a tick, do not panic. Time is on your side if you find the tick and remove it soon after it has attached. The longer a tick feeds the greater chance it may pass on a disease causing germ to you.
American dog ticks. A shield-like scutum covers the entire body in males, but only part of the body in females. (From Kansas State University)
There is only one proper way to remove a tick. Using tweezers, grasp the tick firmly at the base of the head, but do not squish it. Then gently and steadily pull on the tick. Be patient. Eventually it will come out. You do not want to break the mouthparts of the tick off and leave them inside you because infection is likely. Lone star ticks have very long and thin mouthparts, and it is very difficult to always get their mouthparts. Save the tick in some rubbing alcohol just in case you or your child gets sick. It will be of value in disease diagnosis. Clean the bite and treat with alcohol (or hydrogen peroxide) and antibiotic ointment.
Do not remove a tick by any of these methods. Don’t squeeze the tick with your fingers. Doing this will cause the tick to act like a hypodermic needle and you will inject yourself with tick saliva, gut contents, blood, and any disease germs it is carrying. Don’t put oil, petroleum jelly, ointment or other irritating substances on the tick. This will cause the tick to regurgitate its stomach contents into you increasing the likelihood germs will be transmitted. Don’t burn it off with a match, cigarette or anything else. Like oil, heat will irritate the tick and it will puke inside you. Burning a tick off is also a bad idea because even though the tick will die, its mouthparts will still be inside you and likely cause infection. Always get the tweezers, or purchase a tick removal kit (usually a glorified set of tweezers with instructions).
Other disasters can occur if any source of fire is used to remove a tick. When I was a graduate student, my girlfriend’s roommate and her fiancé were trying to remove a tick from their little cocker spaniel, Pepper. I told them to just remove the tick with tweezers. If only they had listened to me. First they applied an aerosol flea and tick killer to the entire dog. Against my protests, they next applied a lit cigarette to the tick. Suddenly there was a whoosh of flame as the chemical ignited and engulfed the hapless cocker. Poor Pepper escaped serious injury, but she lost a good deal of her coat and the smell of burnt hair stank up the apartment. Pepper’s owners lost some eye brows and lashes too.
The best defense against chiggers and ticks is clothing and the use a repellent. Light colored clothing makes it easy to see ticks and remove them, but during hunting this is usually not an option. Tuck your pant legs into your boots. Use a repellent that indicates it is good against chiggers and ticks. Repellents containing 20-40% of the active ingredient DEET (N,N-diethyl-M-toluamide) are among the best and can be placed on the skin or on clothes. Common brands are Off, Cutters, and Ultrathon. Check the label ingredients for DEET. At least one company (Cutters) now offers a repellent with the new active ingredient picaridin. Picaridin is as effective as DEET, but its long term safety had not been as well established as well as DEET. Get good spray coverage on your pant legs, socks, boot tops, and waistline. Repellents containing the insecticide permethrin (also called Permanone®) are also effective. Some brands are Repel Permanone and Sawyer. They are spayed onto clothing, allowed to dry, and remain active for several weeks and washings. Do not apply permethrin to clothes while you are wearing them or to the skin. Permethrin is a nerve agent and the neurochemistry of humans and arthropods is surprisingly similar. With any repellent, always read the label and follow the directions.
Be aware that DEET can melt plastics and take the finish off guns, so take precautions when applying it. I like to wear a pair of cotton gloves when I apply DEET, which I then remove before handling my gun, bow, fishing rod, or other gear. According to the manufacturer, picaridin does not melt plastics or damage some fabrics like DEET does. It is also less greasy than DEET and you might prefer it instead.
The ticks on the buck you shot will be just as happy on you. As their dead host cools and no longer offers a blood meal, ticks will crawl off and begin searching for another host. I don’t advise putting a deer carcass in the back of an SUV for this reason. Eventually the ticks will find the driver or passengers. This can be especially dangerous if the SUV happens to be your wife’s. Be alert for ticks when handling game, especially during field dressing and skinning.
Dogs and cats often bring ticks into homes and then find their way to pet owners. It is wise to control ticks on your pets. Dogs and cats are also at risk to contract Lyme disease, tularemia, and ehrlichiosis. Consult your veterinarian about tick borne diseases and which products to use to protect your Gunner or Fluffy. I have used Frontiline® (which contains the insecticide Fiprionol) for years and kept my dogs tick and flea free. It seems expensive especially when you consider the amount of product your get, but it has been well worth the cost. Frontline has eliminated my need to spend time removing dozens of ticks from my gun dogs. Products only containing the insecticide imidacloprid (for example Advantage®) control fleas but are not effective against ticks. Again consult a veterinarian because these products cannot be purchased without a prescription. Finally, don’t allow teenagers to wear flea collars around their ankles. Besides being hazardous to their health, it will not protect them from ticks nor make them look cool.