Tick-borne illnesses have doubled in recent years and are spreading across the country. Scientists who study these diseases suspect that climate change may be contributing to this epidemic. Many species of ticks have been extending their range into new territory. Because they carry disease-causing pathogens with them, clinicians may not recognize the resulting illnesses at first.
One Bite Can Transmit Multiple Tick-Borne Illnesses:
Lyme disease has spread widely from Old Lyme, Connecticut, where scientists isolated and identified it. However, Lyme disease is not the only problem. A study of ticks on Long Island found that they can carry multiple disease-causing pathogens (mBio, Sept/Oct, 2019). A single tick can transmit more than one disease with its bite. Doctors may find diagnosis more difficult as a result.
More than half of the deer ticks examined carried the Borrelia burgdorferi bacteria that causes Lyme disease. Many also were infected with other species of Borrelia as well as Anaplasma bacteria and Powassan virus. All of these pathogens can cause tick-borne illnesses.
Lone Star Ticks Also Carry Disease, Though Not Lyme:
Lone star ticks (Amblyomma americanum) in the study carried two species of Erlichia. These bacteria can cause severe disease. People bitten by a lone star tick may also develop Southern Tick-Associated Rash Illness (STARI). This may mimic Lyme disease when it presents with fever and a bulls-eye rash. However, scientists have not identified the pathogen that causes STARI. They named it “Southern” because when they identified the syndrome, lone star ticks were found mostly in southern states. Now, however, lone star ticks have spread far beyond their original southeastern territory.
Alpha Gal from Lone Star Ticks:
The meat-allergy syndrome, alpha-gal, can also be triggered by the bite of Amblyomma americanum. We discussed the difficulty of diagnosing Lyme disease and alpha-gal allergy in Show 1003: From Lyme to Alpha-Gal: The Latest on Tick-Borne Diseases. You might also be interested in our most recent interview with Dr. Scott Commins. It is Show 1167: Will a Tick Bite Make You Allergic to Meat?
Rocky Mountain Spotted Fever:
The Long Island scientists found that dog ticks carried Rickettsia that can cause Rocky Mountain Spotted Fever. Although the first clinicians to identify Rocky Mountain Spotted Fever were indeed in the Rocky Mountains, these tick-borne illnesses are now more common in the southeastern US.
The Problem with Tick-Borne Illnesses:
When people are infected by more than one pathogen it may be more difficult to diagnose and treat the resulting diseases. Patients recover well from nearly all of these infections if they are treated promptly and appropriately. However, Rocky Mountain Spotted Fever can be lethal if untreated. Powassan virus can cause severe disease with neurological complications. In addition, people whose Lyme disease is not treated early may suffer joint pain, headaches, facial palsy, heart rhythm problems, nerve pain and other complications.