For decades, the accepted wisdom is that Rocky Mountain Spotted Fever is the most common tick-borne disease in North Carolina. But maybe that’s not the case.

By Yen Duong

Paul Friedheim’s ordeal started in August 2014.

“It was a big fat deer tick,” Friedheim said. “We were hiking right on the North Carolina-Virginia border. I’ve pulled so many ticks off me before and I don’t think it was on there too long.”

Within a few weeks, Friedheim left school with swollen joints and irritable bowels. He tested negative for spotted fever rickettsioses, one of a group of diseases including Rocky Mountain spotted fever, the most commonly diagnosed tick-borne illness in North Carolina.

In 2017, North Carolina had a total of 950 confirmed or probable cases of spotted fever rickettsiosis , Lyme disease or ehrlichiosis in 2017, according to the state Department of Health and Human Services. Of those, 114, or 12 percent, were ehrlichiosis.

But a new paper out of University of North Carolina-Chapel Hill suggests that ehrlichiosis is far more common than previously thought. The study examines 194 records of patients who had been tested for tick-borne illness during summer 2016.

These three tick-borne illnesses require different tests, and 124 patients reviewed were not tested for ehrlichiosis. The authors retested those patients’ blood for ehrlichiosis, and 20 percent of those came back positive, meaning those patients were likely not diagnosed with the correct tick-borne disease when they went to their doctors.

“If you look at the actual tick epidemiology in North Carolina, where they collect ticks off park rangers or people out in the woods, what you find is that 90 to 95 percent of our ticks are lone star ticks,” said study author and UNC epidemiologist Ross Boyce. “It doesn’t really make sense that we are a hotbed of Rocky Mountain spotted fever when the ticks that seem to be on people the most are not ticks that carry it.”

Lone Star ticks transmit ehrlichiosis, while dog ticks carry spotted fever rickettsioses. Almost 80 percent of patients originally took a spotted fever rickettsiosis test, but only a third took an ehrlichiosis test.

“Even though I did medical school here and I did my extra study fellowship here, I came away from that experience believing that Rocky Mountain spotted fever was the tick-borne disease in this area,” Boyce said. “So I think there’s a misperception.”

The difficulties of testing

Even though Friedheim tested negative for spotted fever rickettsiosis, he nonetheless received a prescription for doxycycline, the antibiotic used to treat many tick-borne illnesses.

“The CDC says if you have a high suspicion of a particular disease, just treat, don’t wait for the test result,” Boyce said.

Humans slowly create antibodies in response to a tick bite, which is why those first tests can come back negative, Boyce said. The Centers for Disease Control and Prevention recommends patients take another test four to six weeks later to confirm or receive a diagnoses, after their bodies have ramped up the antibodies in response to a tick infection.

Once produced, those antibodies remain in the body, Boyce said. That person will always get a positive acute test, and only the second, later test will reveal a new infection.

“Unfortunately, typically about 5 to 10 percent of people actually ever get [that second blood] draw because if they get treated, they feel better,” Boyce said. “And who wants to come back to the doctor to get blood work when you feel better?”

Why don’t we know the number of tick-borne illnesses in the U.S.? Naomi Drexler of the CDC wrote in an email: In order to be recorded as a confirmed case of ehrlichiosis and for this case to be reported to CDC: A sick person has to go to the doctor.

The doctor has to suspect ehrlichiosis.

The doctor has to order a test to confirm her suspicions.

The test has to come back positive.

The doctor has to report the case to the health department.

The health department then reports the case to CDC. Underdiagnoses and under reporting can also result if the right samples are not taken at the right time in a person’s illness.

Limited reporting means limited information

Friedheim’s doctor didn’t order a follow-up test. The doxycycline worked and Friedheim went back to school and forgot about the incident.

This lack of follow-up testing means that public health officials have a hard time tracking incidences of tick-borne diseases.

“The reporting criteria are extremely complicated and the reporting requirements are quite high because the CDC doesn’t want false cases in it, they want the minimum that are accurate cases,” said Marcia Herman-Giddens of the Tick-Borne Infections Council of North Carolina (TIC-NC).

She argued that, “Everyone agrees that the cases that end up reported out, called confirmed or probable cases, are just the tip of the iceberg.

“If you go from the fact that these cases that end up on the list are the tip of the iceberg, you know the problem is much worse than the numbers you’re seeing.”

To date, the CDC only requires DHHS to report some, but not all tick-borne diseases, including cases of ehrlichiosis, spotted fever rickettsiosis and Lyme. That means no one knows how many cases of STARI, a disease similar to Lyme, or alpha-gal allergy, the red-meat allergy carried by the lone star tick, have occurred in North Carolina, Herman-Giddens said.

“We don’t know how much of a problem it is, we just know it’s a problem,” said Herman-Giddens noting that the official tally of tickborne diseases in the state numbers in the hundreds per year. “It’s not unreasonable to say that thousands of people are getting tick-borne infections in this state.”

A recent survey of 366 households in Chatham County supports the claim that tick-borne illnesses are underreported. Shannon Godbout of the county public health department emailed that 8.3 percent of respondents had ever been diagnosed with a tick-borne illness, and 57.8 percent said that a member of their household had found a tick on their body within the past year.

Though Chatham has one of the highest rates of reported tick-borne diseases in the state, these results imply that the number of tick-borne illnesses could be higher than the 950 confirmed North Carolina cases in 2017.

The future of tick testing

At the state lab, patient data goes through both ehrlichiosis and spotted fever tests. DHHS gives recommendations, but medical providers choose which tests to run if they use a private lab.

Boyce suggests creating and using a standard tick panel to test all three diseases, which start with similar cold-like symptoms.

“We’re taking his conclusions and recommendations to heart,” said State Public Health Veterinarian Carl Williams. “Spotted fever is the most commonly reported tick-borne illness in North Carolina, but the most common tick is the lone star tick.

“That tick is very common and probably everyone in North Carolina has had one on them at one point or another. What we don’t know is what percentage of them are infected with the bacteria.”

Finding the right diagnosis

Two years after returning to school, Friedheim’s symptoms returned. After going to urgent care several times in Lexington, Va., he ended up in a Charlotte emergency room while visiting his parents. Half of his face was paralyzed, leaving him unable to talk or eat, when doctors at Carolinas Medical Center – Mercy diagnosed him in September 2016 with meningitis caused by Lyme disease bacteria.

Friedheim had only been tested for spotted fever rickettsiosis in 2014, not Lyme.

In 2015, the CDC reported Lyme disease was spreading south and was particularly prevalent in Virginia. As far back as 2012, entomologists from Yale found Lyme disease increasing in North Carolina. Researchers suspect climate change may be moving the lone star tick’s habitat further south and lengthening tick season. Boyce said that means we can expect more tick-borne illnesses.

Sponsored

Friedheim, whose Lyme disease flared up again this summer, urges anyone suspecting a tick-borne illness to seek medical attention. He thinks the 2014 tick bite gave him Lyme disease.

“A lot of people can just pull them off and be fine, but for that percentage that gets affected it’s definitely worth going and taking the trip to the doctor,” Friedheim said. “Since it went for a long time untreated it’s something that’s very hard to get rid of completely. I’m just trying to take it one day at a time.”

What to do if you get bit by a tick, from a TIC-NC pamphlet How to Remove Ticks Safely Grasp the tick firmly with sharp-pointed tweezers, as close to the skin as possible. Pull straight out slowly and steadily. Use alcohol on bite site and tweezers. Wash hands thoroughly. Keep the tick. Tape it to a card. Write the date and where it bit. If you develop an infection this information could be helpful. Watch for flu-like symptoms and/or rashes for 30 days. Dangers of Improper Removal Do not squeeze, burn or use products on the tick. This may irritate the tick, causing it to regurgitate infected bodily fluids into the wound.

Do not use bare fingers. Infected fluids from the tick could enter tiny cuts in your skin.

Do not twist the tick. This can cause the mouthparts to break off and remain in the wound.

Correction: This story has been altered to note that the NC DHHS tests for some other tick-borne diseases beyond erlichiosis, Lyme and spotted fever rickettsiosis.