By Chris Williams on August 21, 2017.

Deer ticks (correctly called blacklegged ticks) are our smallest disease-carrying ticks. And that’s part of the problem. All stages of this tick can carry and transmit Lyme disease: larval stage, nymph, and adult tick. One of the reasons they can so easily attach and feed is that they are so hard to see. The adult tick is only about the size of a sesame seed and the immature ticks are even smaller, with the larval stage being the size of a poppy seed.

Now scientists announce the discovery of a new, even smaller deer tick, first seen in 2015. Researchers at the Connecticut Agricultural Experiment Station found an adult female deer tick that is half the size of a normal adult female, at only 1/16 inch long, the first deer tick known to exhibit dwarfism. There is some evidence that ticks with such abnormalities are more efficient as disease vectors.


This is not good news since the percentage of Lyme-infected deer ticks is at an all time high thanks to warmer winters that no longer kill off as many ticks. In addition, weather has extended the tick season with ticks becoming active earlier and remaining active later, giving more opportunity to acquire and transmit disease. In some areas, ticks remain somewhat active all winter long. Connecticut’s Tick-Testing Laboratory normally receives about 50 ticks for testing during a typical winter but this past winter they received 800.

More ticks are infected with the Lyme disease pathogen, too. The infection rate among deer ticks is typically 27 to 32%, but so far in 2017, the Lab says that infection is running at 38% with up to 50% of ticks in some areas being infected with Lyme disease (see Will There Be More Lyme Disease Ticks This Year?).

But the celebrity dwarf tick may be an anomaly that is not destined to become part of the general population. Researchers report finding other deer tick abnormalities such as extra legs, in certain sampling locations. Similar tick abnormalities in Europe are being blamed on heavy metals but U.S. researchers think environmental changes such as higher-than-normal temperatures and humidity may be factors for abnormalities in U.S. ticks.

In the Northeast, the hotbed of Lyme disease, tick season is well underway and could last for a few more months. Be sure to wear repellent in tick areas and be proactive by removing tick habitat and wildlife attractions in your yard (Take Steps to Keep Ticks Out of Your Yard).

Photo Credit : Fritz Flohr Reynolds | CC BY-SA 2.0



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