Testing ticks for disease can still leave questions

A female deer tick is shown under a microscope.
Victoria Arocho | AP
A female deer tick is shown under a microscope.
Posted Aug. 16, 2012, at 6:28 p.m.

When Maine is in the throes of tick season, huge bags of the eight-legged bugs arrive for testing at a Maine Medical Center lab in South Portland.

Most of the specimens are squashed, ripped apart or burned, evidence of their victims’ efforts to remove the tiny arachnids after a bite.

“It looks like people have taken a blowtorch to them to get them off,” said Charles Lubelczyk, field biologist at the MMC Research Institute’s Vector-Borne Disease Laboratory.

The samples come in baby food jars, contact lens cases, zip-lock bags and all manner of containers.

Many people who send ticks to the lab for testing are worried about disease, but the lab’s researchers do not test submitted bugs for Lyme disease or other illnesses. No lab in Maine does, including the state lab overseen by the Department of Health and Human Services that performs rabies and lead testing.

For those who want a tick checked for disease, and are willing to pay, the closest options are the University of Massachusetts Amherst and the University of Connecticut. The UMass testing program charges $40 per sample, while the UConn lab charges $50 to $100.

MMC’s lab, at no cost, identifies the species of tick — there are 15 in Maine — and determines how long a tick was attached to its host based on the amount of blood in its tiny body.

Both pieces of information are useful in determining whether someone is likely to get sick from a tick bite. While some species don’t pose a risk to human health, the deer tick, which is spreading farther north into Maine, is known to transmit Lyme disease as well as two other illnesses emerging in the state: anaplasmosis and babesiosis.

In areas where the deer tick is more prevalent, such as York and Cumberland counties, up to 70 percent are estimated to carry disease, Lubelczyk said. The infection rate is about 40 percent in the Bangor area. It drops further in Aroostook County and Down East, but submissions from those regions are increasing, he said.

No matter where you are in the state, “the potential for infected ticks is going to be out there,” Lubelczyk said.

Deer ticks carrying disease must be attached for 36 to 48 hours to spread illness through a bite, he said.

Even then, the tick may or may not actually make you sick, according to Dr. Stephen Sears, state epidemiologist. Testing can tell you whether the tick that bit you carries an illness-causing organism, but not whether you’ve been exposed to the disease, he said.

“Even though a tick may be infected, it does not always transmit disease,” Sears said.

If you’re bitten by a deer tick that clings to your body for at least 24 hours and is engorged with blood, health practitioners assume the potential for disease, he said. Doctors may recommend a dose of antibiotics and patients must monitor themselves for symptoms for about a month, he said.

Health practitioners do not, however, recommend the blowtorch approach to tick removal. If you spot an embedded tick, use tweezers to grasp its mouth and pull it out with steady pressure. Don’t use petroleum jelly, hot matches or nail polish remover, which can increase the risk of infection.

MMC’s lab typically tests 1,000-1,600 ticks a year, Lubelczyk said. Submissions come from state and federal agencies, doctors, veterinarians and the public.

The lab would need a clinical certification to test submitted ticks for disease, he said. But its researchers will collect tick samples from the field, such as at state parks, and test them for pathogens that cause illness. That’s how the lab comes up with its estimates about the number of ticks in a given area and how many carry disease, Lubelczyk said.

The lab also conducts research into illnesses carried by mosquitoes, such as West Nile virus and Eastern equine encephalitis.

For ticks, the lab generates a report identifying the species and engorgement level within a couple of days.

Then the tick goes into storage, joining the lab’s racks and racks of specimens dating back to the 1990s, Lubelczyk said. Researchers hold onto the little bloodsuckers just in case further testing is needed down the road.

“All the deer ticks that come through the door we do hold on to,” he said.

For information about submitting a tick to the Vector-Borne Disease Laboratory, visit www.mmcri.org.

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