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The Lone Star Tick

By Ed Robinson

There has been extensive media coverage in recent years regarding tick borne diseases in Maine. The most common of these is Lyme disease, but anaplasmosis and babesiosis are rapidly growing in prevalence here. The primary carrier of the bacteria causing those diseases is the black-legged tick, often called the deer tick. Maine unfortunately is now host to another tick that can carry additional diseases affecting humans, the lone star tick.

The native habitat for the lone star tick is the southeastern US but in recent decades it has expanded its territory to the north, probably because climate change allows them to survive milder winter weather here. Ticks are spread by mammals, from mice to deer, and also birds including turkeys and migrating thrushes. Lone star ticks are now showing up regularly in Maine surveys and have been documented well into Ontario, Canada.

While lone star ticks may carry the bacterium that causes Lyme disease, it does not appear that the ticks are capable of spreading the disease to humans. That is of limited value, however, because lone stars are carriers of other bacteria that cause potentially serious disease. Some who suffer lone star bites will display a rash and inflammation around the site, mimicking the early rash of Lyme disease. This condition is now known as STARI or Southern tick-associated rash illness. More serious are various forms of Ehrlichiosis, which manifests with flu-like symptoms, sometimes severe enough to require hospitalization. Another disease is tularemia, far more common in rabbits and hares than in humans but fever, inflammation and joint conditions may be severe enough in rare cases to cause death. Perhaps the most serious, but fortunately rare, is Rocky Mountain Spotted Fever, which puts most patients in the hospital with severe headaches, cramping, inflammation, joint pain and possible death. The only good news here is that all of these conditions may be treated by antibiotics.

A particularly vexing issue with lone star tick bites is the likelihood of developing a serious allergy to red meat. This is triggered by a severe immune system response to an oligosaccharide known as alpha-gal. The allergic reaction is not an immediate one as is commonly the case with allergies to seafood, but may be delayed as long as eight hours. The allergic response may include anaphylaxis, causing a patient to experience a narrowing of the airway that, if not treated, may lead to suffocation. Research is still underway but there is reason to believe that this allergy, once acquired, is permanent.

Like deer ticks, lone star ticks favor brushy cover in hedges and over-grown fields and forests with lots of understory. The larval, nymph and adult stages of the tick all need to feed on blood to develop to their next stage of life. While deer ticks heavily favor mice and white-tailed deer for their blood meals, lone star ticks are willing to take their blood anywhere they can find it, including dogs and cats.

Once attached, they can feed as long as eight to ten days on humans, and the bite is not painful so you may not notice the tick if it is in a hidden crevice. Once an adult female has fed, she lays up to 5,000 eggs on the ground and dies.

Lone Star Tick (Amblyomma americanum) on a white background (Photo by epantha, iStock)

Lone star ticks are nearly round in shape, with the female having a prominent white dot or star on her shield. They are larger than deer ticks, but in the early stages they are still hard to spot on clothing or your body. Lone star ticks are considered aggressive in that they will move considerable distances to attach themselves to a host, hanging from low vegetation or moving around your home if carried indoors inadvertently. They react to carbon dioxide, body heat and vibrations that indicate a living host is nearby.

As with deer ticks, prevention is critical to avoid tick bites. The best advice is to protect yourself by using repellent on skin or clothing and using gaiters or tucking pant legs into your socks. While outdoors, be alert to ticks on your clothing or body for immediate removal. Once you are back indoors, place clothing in the dryer on a high temperature setting for at least 10 minutes. Check your body carefully, asking for help for those places that are out of sight. A thorough shower with toweling off and combing of hair may dislodge a tick that is not yet fully attached.

For more information on protecting yourself from tick bites, please refer to my previous articles on this website. Click here to read more.

June 2020