A mild winter and an early spring have led to a fast start to tick season in Central Oregon and around the state.
The Oregon Lyme Disease Network, a Bend-based nonprofit educating the public about Lyme disease and other tick-borne infections, has already received a flood of calls from people in Oregon bitten by ticks this year.
Calls during the first quarter of the year nearly matched the total from the 2017 second quarter, and four weeks into the 2018 second quarter, calls are running at nearly double last year’s rate.
“I don’t know if that’s because we have done such a good job raising awareness that people know where to go or because the problem is worse,” said Theresa Denham, the group’s president.
Typically, the network gets calls primarily from Southern Oregon and the Hood River area, and fewer from Portland or Central Oregon.
“But this year, it’s really dispersed pretty evenly everywhere, which scares me,” she said. “I think the fact that it was warmer earlier this year, during the time that ticks are becoming active, people were out more this year. Last year, we were covered in snow this time of year.”
Tick season generally starts once the snow cover is gone and nightly temperatures stay above 40 degrees.
“That’s when ticks are going to become a lot more active,” said Emilio DeBess, Oregon’s public health veterinarian. “Sometimes we see them earlier in the year because it kind of warms up for three or four days and they basically go nuts.”
That’s just when people are shaking off their cabin fever, hitting the hiking or biking trails and visiting campgrounds or their favorite fishing spots, often in tick-infested areas. Three types of ticks are prevalent in Central Oregon: the black legged tick, the Pacific Coast tick and the Rocky Mountain wood ticks.
State officials track the severity of tick seasons based on the number of tick-borne diseases reported, primarily Lyme disease, ehrlichiosis and babesiosis, but also 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.
“The trend throughout the U.S. is upward, and I think we see that in Oregon as well,” DeBess said. “What we’re trying to understand is, is there an upward trend based on climate or is there an upward trend because everybody is looking for it?”
The Centers for Disease Control and Prevention released new data Tuesday showing that the number of diseases transmitted by ticks and mosquitoes has tripled nationwide over the past 13 years, including a doubling of diseases carried by ticks.
“Keep in mind that many infections are not reported or recognized, so it’s difficult to truly estimate their overall cost and burden,” said Dr. Lyle Petersen, CDC director of vector-borne diseases. “We know that the number of Lyme disease cases that actually occur each year are approximately 300,000, or 10 times higher than what is nationally reported.”
Many cases of Lyme disease go unrecognized, he said, and even when patients are properly diagnosed, doctors don’t always report those cases to the state. Some states see so many cases that health departments can’t keep up.
“What’s important here is the actual trends,” Petersen said. “Even though we don’t count every single case, we know that the trend is toward a worsening in the United States, where more tick-borne diseases are found in an increasingly wide area.”
While CDC officials are confident of the trend line, explaining the increase is tricky. Transmission is dependent on environmental factors, such as rainfall and temperatures. Many of the diseases are transmitted by ticks and mosquitoes from animals or birds. And human behavior, such as outdoor recreation or urban sprawl, often brings people into areas where infection is more likely.
“There are many more deer in the areas where people live,” Petersen said. “With more deer, you have more deer ticks, and with more deer ticks you have more Lyme disease or anaplasmosis or a number of other diseases they spread.”
Rising temperatures, possibly due to climate change, also expand the range of ticks further north and extend the season during which people can get infected.
Petersen said that funding provided by Congress to battle the Zika virus has helped state and local health departments and other mosquito or tick control agencies prepare for the risk of tick- and mosquito-borne diseases. But he cautioned that sustained funding over the long term would be needed to combat a rise in the number of cases as well as an accelerating trend of new diseases. Since 2004, nine diseases transmitted by ticks or mosquitoes were found in the U.S. for the first time.
Oregon health officials recommend using mosquito and tick repellents such as DEET or permethrin, and doing body checks for ticks after spending time outdoors.
“If you’re out and about, daily checks are a must,” DeBess said. “You have to check yourself under the arms, in the groin area, all the spots where they tend to hang out.”
DeBess also suggests talking to veterinarians about the best products to protect pets, which can bring ticks indoors and increase the risk of infection.
The Oregon Lyme Disease Network recommends people bitten by ticks send them in for testing. Test sites, including TickReport.com and TickNology.org, can test ticks and determine whether they carry any infectious diseases. Testing starts at $25 to $50 per tick.
Infections, Denham said, often start with vague flu-like symptoms that may wax and wane, but never really go away. Only about 1 in 5 people infected with Lyme disease will have the tell-tale bullseye rash.
“People also don’t understand that different ticks cause different things,” Denham said. “A lot of people go get tested for Lyme disease and it comes back negative, and they don’t know where to go from there.”
— Reporter: 541-633-2162, firstname.lastname@example.org