The number of Minnesotans with tick-borne disease jumped to record levels in 2010.
The state Department of Health said anaplasmosis now rivals Lyme disease.
Dave Neitzel, MDH epidemiologist specializing in tick-borne diseases, said it’s a continuing and troubling trend.
Aitkin, Cass and Crow Wing counties are on a short six-county list in the state where anaplasmosis cases exceeded Lyme disease last year. The culprit is the small black-legged tick, commonly called the deer tick after their familiar woodland host.
Anaplasmosis can be severe, even deadly. The state health department reports about 30 percent of the 720 anaplasmosis cases last year resulted in hospitalization. One patient died. Statewide the anaplasmosis cases shot up, more than doubling from the 300-plus cases reported in recent years.
Because the deer ticks in the nymph stage, which feed in the spring, carry the disease along with the adults, people may be bitten but never know it. The illness comes without the often tell-tale rash associated with the bite of a Lyme disease carrying deer tick.
And Lyme disease cases have continued to climb. Cases increased in the state by 21 percent between 2009 and 2010 with 1,293 cases reported.
There are fewer babesiosis cases. But they are also climbing. In 2010, there were 56 cases statewide, up from 31 in 2009. Nearly half of the babesiosis cases resulted in hospitalization last year. One person died.
And just to add to the mix, a new tick-borne disease — not detected in Minnesota before 2008 — is here now. It’s called the Powassan virus. Neitzel said the disease is somewhat related to the West Nile virus in the way it invades the central nervous system with a rapid onset of headaches, high fever, stiff neck and disorientation. It acts on the body in a way that is similar to encephalitis or meningitis. There is no direct treatment other than supportive care until the virus passes.
Luckily, there have been just a few cases reported — just six in the past two years statewide.
For the more familiar Lyme disease, which has become an annual illness for people who work in the woods, the symptoms include the expanding rash, headache, fatigue, muscle aches. Symptoms may be severe, including facial palsy, heart beat problems and joint swelling to such an extreme it leads to arthritis. The disease is treated with antibiotics and while people do develop antibodies, they may be reinfected with a new tick bite.
Neitzel said the severity doesn’t appear to change with reinfections.
But health officials said the best response in all cases of tick illness is to seek medical treatment as soon as possible.
Kari Springer, disease prevention and control coordinator in Crow Wing County, said the tick-borne diseases appear to have been around for a long time, but the increase in people infected is attributed to a larger population, more interaction with nature and a greater medical understanding and diagnosis of the disease.
On Tuesday Neitzel was traveling the backroads of Camp Ripley in the sweltering heat on a mission to gather ticks for lab study. The ticks are collected by dragging a cloth across the ground through the ticks’ preferred habitat in the leaf litter of the forest floor. The cloth may pick up 20 to 30 ticks after being dragged 65 to 98 feet, but there are likely more ticks out there than those caught out feeding.
In dry conditions, ticks crawl down to the forest floor. On humid and wet days, ticks crawl up a few inches and wait for a host to walk by so they can attach and begin their search for a preferred bite spot, such as an arm pit, the head, or places of constriction. On those days, Neitzel said the ticks are out feeding in number.
At Camp Ripley, Neitzel’s goal was to take the ticks gathered back for testing to see what diseases they are carrying and at what frequency. In general, one out of three adult deer ticks carry Lyme disease. For anaplasmosis and babesiosis, Neitzel said 5 to 10 percent of the ticks are disease carriers.
“We really want to stress to people in your area that there is more than just Lyme disease out there,” Neitzel said. “And also stressing this is a high-risk time of year this is a time of year to take personal protective measures against ticks.”
Coming in Thursday’s edition — more details on varying symptoms of tick diseases, ways to protect from tick bites and a more in-depth look at reported cases in the five-county area.
RENEE RICHARDSON may be reached at firstname.lastname@example.org or 855-5852.