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Ordinarily I would not be writing about ticks this time of year, but an interesting thing happened when I took our family black lab, Jake, to the vet a few days ago. After the normal examine, shots and blood work, we received a phone call that Jake had been exposed to Lyme disease. We apply a ‘pour-on’ flea and tick insecticide on Jake monthly, year round, but still Jake had been exposed to this disease. The unusual part is that we live in an area of the state in which it is rare to hear about Lyme disease infections. Typically we will find the American dog tick or lone star tick in our area of the state, and neither is a carrier of Lyme disease.
The black-legged tick, also called the deer tick, is the main vector of Lyme disease in the eastern US. While LD is established in the northeast and north central states, few cases have been reported in southern states. Records show very little chance of acquiring the disease in Kentucky. In the past year or so this tick has been showing up in several eastern Kentucky counties, but not in our area. I emailed my information to Lee Townsend, UK Extension Entomology Specialist, and he informed me that he had received two black-legged tick specimens from Trimble County in the past several weeks.
A study was done in Tennessee on the blacklegged tick and Lyme disease by ME Rosen and the information found is believed to be appropriate for Kentucky. Researchers doubt that Lyme disease is established in Tennessee for several possible reasons: 1) The black legged tick is not abundant enough to maintain the pathogen; 2) The tick’s seasonal life cycle in the south is different from the north so the Lyme disease transmission cycle is disrupted; 3) Skinks and lizards, apparent principal hosts of an immature stage (nymph) of this tick in the south are not suitable hosts for the Lyme disease bacterium. In the north, nymphs mostly feed on small mammals which can support the pathogen. The nymphal stage of the black-legged tick is believed to be the one that plays a significant role in LD transmission to humans where the disease is a problem. There have been no known collections of nymphs from humans in Kentucky.
The risk of acquiring Lyme disease in Tennessee (and Kentucky) is considered to be very low because this tick is present at low levels and rarely bites humans. In addition, adult blacklegged ticks that do bite humans are very unlikely to be carrying the Lyme disease pathogen. However, a dramatic increase in tick numbers increases the chances for human contact and bites.
The black-legged tick is a three-host tick; its life cycle may take 2 years. Males and females seek and attach to large mammals (dogs, deer, and humans) from November through April. Females mate and feed for 5 to 7 days to engorge with blood. When full, they will drop from the host to produce and deposit a mass of 1,000 or more eggs on the ground.
A 6-legged larva hatches from the egg in the spring and waits for a passing host, a lizard, skink, or mouse. It will spend 3 to 5 days taking a blood meal, then drop off and molt to the nymphal stage.
Nymphs are inactive on the ground for the rest of the year. They will wait for a small animal host, attach and feed again. After this second meal, they will detach and drop to the ground to digest their meal and molt to the adult stage. Adults follow the same steps, except they will be attached to a large animal host. Males feed very little. Females die after laying their eggs.
Following is some general information to help protect you from ticks this year:
• Avoid wooded, bushy, or grassy areas whenever possible.
• Wear light-colored clothing with long sleeves and long pants. Ticks are easier to see against a light background.
• Check yourself carefully after you’ve been outdoors. Ticks wander on the body for some time before settling to feed. Those attached to visible areas are easy to see but they will also settle in armpit, groin, and scalp, areas that are more difficult to examine thoroughly.
• Remove ticks promptly: If you find a tick, use narrow-tipped tweezers to grasp it as close to your skin as possible, and pull upward slowly and steadily. Then, wash your skin and hands with soap and warm water. Never crush or squeeze an attached tick.
If you find ticks on adults, children or animals bring them to the Trimble County Extension Office at 43 High Country Lane, Bedford, Kentucky. It will help Extension Entomology Specialists get a better idea of the ticks that occur in Kentucky and when they are active. You can also mail the specimens to the Department of Entomology, Identification Lab, S-225 Ag Science – North, Lexington, KY 40456-0091.
Michael Pyles is Trimble County’s Cooperative Extension agent for agriculture.