Summertime is tick season. As soon as temperatures start to climb, ticks come out of hibernation. That’s bad news for pets and people who like to get out into nature. Tick-borne illnesses have doubled in recent years and are spreading across the country.
Lyme disease, while potentially serious, is not the only problem. Also known as borreliosis, Lyme disease is an infection by Borrelia burgdorferi bacteria. It has been spreading from New England to mid-Atlantic states, the upper Midwest and as far west as California, Oregon and Washington.
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. These recent arrivals carry disease-causing pathogens with them. However, when they are new, 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 disease that deer ticks (Ixodes scapularis) transmit. Researchers report in 2022 that there has been an increase in anaplasmosis and babesiosis in upstate New York. Tick-borne pathogens cause both diseases. Deer tick virus, also known as Powassan virus, is on the rise.
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 of them also carried 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. Initially, the lone star ticks that carry the disease lived mostly in southern states. Now, however, lone star ticks have spread far beyond their original southeastern territory.
Lone star ticks also seem to be the primary culprits transmitting Heartland virus. This disease was first identified at the Heartland Clinic in northwestern Missouri in 2009 (Missouri Medicine, Jul-Aug. 2016). Symptoms include fever, fatigue, muscle pains, diarrhea, headache, nausea and low white blood counts. Because this infection is caused by a virus, there are no effective treatments. Avoiding tick bites is the best approach.
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 wish to listen to our interview with Dr. Scott Commins. It is Show 1167: Will a Tick Bite Make You Allergic to Meat? Our most recent interview with Dr. Commins and his colleague, gastroenterologist Sarah McGill, is Show 1344: Managing Meat Allergy and Other Tick-Borne Diseases. Both doctors are superb communicators, and you will learn a lot if you listen.
The CDC has also been learning about this condition. One thing it has learned is that two out of five healthcare providers surveyed were unfamiliar with alpha gal syndrome (MMWR, July 28, 2023). Sadly, this substantiates the reports we have heard from many visitors that providers may not be knowledgeable or helpful. That is changing as alpha gal syndrome becomes more common. And it is becoming more common. The CDC has documented 110,229 suspected cases from 2010 to 2022. Its experts estimate, however, that is an underestimate. As many as 450,000 people may be affected (MMWR, July 28, 2023). That means nearly half a million people could be in serious danger if they consume meat or animal products, including something like gelatin.
Babesiosis Is Included in Tick-Borne Illnesses:
Now the CDC is concerned about another tick-borne illness (MMWR, March 17, 2023). Babesiosis is the result of infection from a microscopic parasite called Babesia microti. The first case was identified in 1969 on Nantucket Island. Since then, it has been spreading throughout the northeast wherever deer ticks are found. The parasites hang out in red blood cells.
The illness can range from mild to severe. Symptoms include fever, headache, muscle aches and joint pain. Left untreated it can lead to kidney failure, blood disorders and severe breathing problems. Doctors treat this infection with a combination of azithromycin and atovaquone.
Babesiosis is showing up in New York, New Jersey, and Minnesota, suggesting that the parasites are migrating along with the ticks that harbor them. It is only a matter of time for this disease to become widespread.
Asian Long-Horned Ticks Bite Humans, Too:
Entomologists have also noted the spread of the Asian long-horned tick (Haemaphysalis longicornis) in Connecticut. This tick is a relatively recent arrival first noted in the US in 2017. At this time, however, people have reported them from multiple states, including Arkansas, Connecticut, Delaware, Georgia, Kentucky, Maryland, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia. Contrary to initial reports, this tick does not seem averse to biting humans, and it may be able to spread Rocky Mountain spotted fever.
Rocky Mountain Spotted Fever:
The Long Island scientists cited above 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 more than one pathogen is present, doctors may have more trouble diagnosing and treating the resulting diseases. When health care providers use prompt, appropriate treatments, patients recover well from nearly all of these infections. However, Rocky Mountain Spotted Fever can be lethal if untreated. Babesiosis, too, can kill those with compromised immunity. Powassan virus can cause severe disease with neurological complications. In addition, if Lyme disease is not treated early, infected patients may develop joint pain, headaches, facial palsy, heart rhythm problems, nerve pain and other complications.
Preventing Tick Bites:
Mild winters mean more ticks. Prevention is always the best strategy. Using repellent on shoes, socks and pants can discourage ticks. Tucking pants into socks and wearing gaiters coated with permethrin can also help. People should also conduct conscientious tick checks whenever they come inside. Finding and removing a tick early can often forestall infection.