Central Oregon a Hot Spot for Colorado Tick Fever

Markian Hawryluk | The Bulletin | July 7, 2018

In just over a month, Central Oregon has seen at least four confirmed cases and one suspected case of Colorado tick fever, a sometimes painful but rarely fatal tick-borne virus usually diagnosed in only one or two Oregonians per year.

According to the Oregon Health Authority, eight of the 11 confirmed cases of the condition statewide since 2011 have been Deschutes County residents.

“I think that’s pretty good evidence that Deschutes County is kind of a hot spot for it,” said Dr. Paul Cieslak, medical director for communicable diseases and immunizations at the Oregon Health Authority’s Public Health division. “Three cases in a short period is a lot.”

Four of the cases involved Deschutes County residents, while the fifth was a resident of Jefferson County.

The federal Centers for Disease Control and Prevention says the Rocky Mountain wood tick, which can carry the disease, is usually found at elevations between 4,000 and 10,000 feet, mainly in the northwestern United States and southwestern Canada. Ticks like to climb tall grass or brush where they can latch onto a new host for a blood meal.

“The high desert area of Central and Eastern Oregon are where we would expect to see it,” Cieslak said.

The three confirmed Deschutes cases were diagnosed by Dr. Jon Lutz, an infectious disease specialist with Summit Medical Group Oregon.

“All three had recognized tick bites. They were all engaging in outdoor activities,” Lutz said. Two patients were hospitalized, and all three had a low white blood cell count that tipped Lutz off to test for Colorado tick fever. Blood samples must be sent to the CDC for testing, and patients are generally well on their way to recovery before their diagnoses are confirmed.

“It’s pretty usually a self-limiting viral infection,” Lutz said. “There’s no effective antiviral therapy for it. There’s no vaccine for it.”

In rare cases, the infection has led to viral meningitis or encephalitis, and pregnant women can be at risk for spontaneous abortions or birth defects.

“About 50 percent of cases have a saddleback fever, where the fever goes away for a few days and then comes back” he said.

A spotted rash occurs in up to 12 percent of cases. The virus cannot be passed from person to person.

Alfalfa resident Stephanie Samples, 55, contracted the condition in May after watching a cattle-branding on a ranch east of her home. Two days later, she pulled off an engorged tick from the back of her knee, but the tick’s head remained embedded in her leg.

“That grossed me out, so I went to (urgent care),” she said. “They looked at it; they talked to several doctors, but they wouldn’t take it out.”

Doctors gave her some antibiotics and sent her home. Two days later, Samples woke up with a severe headache and vomiting. Her son drove her to the emergency room at St. Charles Bend. At first, it didn’t occur to her that the illness might be related to the tick bite. But once she got to the hospital, she recalled her neighbor had faced months of health issues after a tick bite.

Samples had a fever of 102 and she could feel the sweat rolling down her back. Doctors gave her medications for her pain and admitted her to the hospital, where Lutz told her he suspected Colorado tick fever. She was weak and disoriented but, on her third day in the hospital, was feeling much better, and she was discharged.

Two days later, her fever and headache returned.

“It was hurting so bad I thought I was going to die,” Samples said. Her husband called paramedics, but there was little they could do. She wrapped her head in a cold towel and suffered through two more days before she recovered.

A month later, she still does not feel 100 percent, and has some lingering memory issues.

“I feel pretty tired, and I’m a pretty active person,” she said. “There are some days where I feel like I have a hat across my forehead, just because of how much it hurt.”

Charles McGrath, 74, had developed a fever and malaise in late May, but with no respiratory symptoms figured it wasn’t just the flu. His girlfriend, who knew several people affected by Lyme disease, suggested they check for ticks. Sure enough, they found one on the back of his leg.

“I went to the ER at that point, tick in hand,” said McGrath, president and chief scientific officer of Grace Bio-Labs in Bend.

He suspects he was bitten while working his ranch outside of Post, along the Crooked River.

“I’m out in the brush all the time,” he said. “I’ve been out on this ranch for 20 years, and I’ve never had a tick. Assuming it came from the ranch, this would be the first one.”

Doctors sent him home from the emergency room with a course of antibiotics, and McGrath felt better a few days later. But Dr. Lutz had told him he suspected Colorado tick fever because of his low white blood cell count. Confirmation came from the CDC just last week.

It’s unclear why so many cases have occurred in Central Oregon in such a short span of time. It could represent a higher number of rodents infected with the disease or a larger tick population this year. Earlier this year, the Oregon Lyme Disease Network reported getting a high number of calls about ticks after a mild winter and an early spring.

“We’ve tested hundreds of ticks from this area, and they have a lot of stuff, but I have never had a tick come back positive for this,” said Theresa Denham, president of the Bend-based tick information clearinghouse.

Denham urged people who suspect Colorado tick fever to be tested for other conditions as well. Ticks in Oregon can carry more than 30 different infectious diseases, including Lyme disease, ehrlichiosis, babesiosis, Rocky Mountain spotted fever, relapsing tick fever and tularemia. Lyme disease is less prevalent in Oregon than on the East Coast — and less common in Central Oregon than in other parts of the state. But Oregon has seen a steady rise in various types of tick infections over the years.

Precise numbers for Colorado tick fever infections nationwide are hard to come by, as most states do not require doctors to report the condition to public health officials when it occurs. While Oregon does require notification, Cieslak said it’s likely that many cases are going undiagnosed or mistaken for the flu. Symptoms include fever, headache, lethargy and malaise.

“The illness is often gone in three days and virtually always gone in a week,” he said. “Just around the time you’re thinking maybe I’ll go see a doctor, you’re getting better.”

CDC researchers have published at least two studies trying to track the incidence of Colorado tick fever using public health records in Montana, Wyoming and Utah. They found 91 cases from 1995 to 2003 and 75 cases from 2002 to 2012. A 2010 study that collected ticks at 27 sites in Grand Teton National Park and Bridger-Teton National Forest in Wyoming found that 21 percent carried the virus.

Ticks pick up the virus when they feed on small rodents, ground squirrels or porcupines. Cases tend to spike in the late spring and early summer, when ticks are looking for a blood meal and people are heading outdoors for work or recreation.

“This is a discomforting and inconvenient disease, but it’s not a lethal one,” said Dr. George Conway, director of the Deschutes County Health Department. “It’s not readily treatable, but it’s not like one of the scourges of humanity. It’s more of a nuisance.”

With no treatment or vaccine for the virus, public health officials stress good tickborne illness prevention strategies, including wearing long pants tucked into socks when walking in high grass or brush, using repellents such as permethrin and DEET, and doing regular body checks.

Both Samples and McGrath said they’ve become extremely careful about checking for ticks.

“If I see a little black speck, I start smacking it,” Sample said. “I’d sooner have another baby than go through this again.”

McGrath said he is using an insect spray before working on his ranch and checks himself for ticks twice a day.

“I watch it like a hawk,” he said. “I’m very careful.”

—Reporter: 541-633-2162, mhawryluk@bendbulletin.com


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