IOP 2020 Field Research Report

2020 Ixodes Outreach Project Report

Field Research Report 

In 2020 the Ixodes Outreach Project staff conducted two active field research projects in Carlton County, MN.  Our first was a typical tick drag, where our lab staff pull a weighted cloth through a predetermined area, called a transect, while walking a measured path.  Every 10 meters, the cloth is examined to see if any ticks have grabbed on.  Check out a short video of what a tick drag looks like:

 

We monitored the transect from April through October.  Over all we found 84 ticks and 18 of them were Ixodes scapularis, the tick that can transmit the bacteria responsible for Lyme disease.  The bulk of those I. scapularis ticks were caught between late April and early June, with the peak being the 3rd week of May.

We also experimented with a new tick collecting method, a dry ice trap.  Ticks are believed to be able to sense carbon dioxide exhaled by potential prey.  The carbon dioxide gas released as dry ice melts is thought to be a way to attract ticks searching for a meal.  We tested two different styles of trap, and appeared to have relatively equal success.  Our trapping process was started later in the summer, so we missed peak tick season, but ticks are out until snow falls again.  And, indeed we did catch several ticks in September and October with our traps.  

Two different trap designs

Male Dermacentor variabilis tick caught on tape used to hold trap fabric in place

Next year we plan to experiment with other carbon dioxide releasing methods in hopes of developing an inexpensive trapping method that can be used more frequently and at multiple locations.  Stay tuned in 2021 to see how this project unfolds!

Post by C. Fisher

Tick trapping has a good first season in 2020

Part of the work we do at the Ixodes Outreach Project is monitoring and studying ticks, which involves going out into the field and trying to capture ticks where they live and feed.

This season we experimented with a new collection method, tick traps.  Our traps are simple in design, but seemed to yield good results for their first season.  We unfortunately didn't get them rolled out until a little past peak Ixodes scapularis season, but every time we put out the traps we caught at least one tick of some species.   

Here you see our undergraduate researchers building our traps from small Styrofoam coolers.  We tried two designs, one with holes at the bottom for CO2 to diffuse through, and one with holes near the top.  We wrapped the sides of our top-hole version and created a short "skirt" which flared out from the bottom of the cooler with the same fabric our drag cloths are made from to provide a good grip for our climbing and questing ticks.  For the bottom-hole style we simply set these on top of a square of this same fabric and weighed it down with stones to help prevent it being flipped up by wind.

Once the traps were assembled, they were filled with dry ice pellets, which are frozen CO2 gas.  Other researchers have suggested that ticks can sense CO2 breathed out by potential prey and seem to be attracted to it during questing.

The traps were left overnight (approximately 18-24 hours) in locations were we frequently catch ticks during dragging.

A male Dermacentor variabilis tick stuck to the sticky side of the duct tape holding the fabric to the top-hole trap is shown in this last photo near the edge of the duct tape.

These simple traps are reusable, and fairly inexpensive.  Next spring we hope to have our traps out early in the season and test their effectiveness when questing ticks are at peak activity.  The idea is to continue to refine our trap design and potentially launch a citizen science project where we can provide traps to community members who are willing to help us capture ticks for our research.  If funding and refining our trap goes well, we hope to offer traps to the community within the next year or two.  Stay tuned!

Photos and text by C. Fisher

The Trouble with Nymphs

Photo provided by David Schmipf

As ticks molt out of their larval phase, they enter their "teens," gaining their seventh and eight legs and, as you might expect from other teenage species, become much more trouble than their larval stage counterparts.

Nymphal Ixodes scapularis ticks are still very small, about 1-1.5mm, although this is a little larger than a larva.  They tend to look like a very small adult female, having a very dark brown or black scutum that covers half to 2/3rds of their back and a pale tan or red brown posterior end.  To the right we have a photo of three nymphs on a 1mm grid and shown above the ticks is a poppy seed for size reference.  On the left we have an I. scapularis nymph, in the middle is a Dermacentor variabilis (also known as the dog or wood tick) nymph and on the right is an Amblyomma americanum (also known as the lone star tick) nymph.

Ixodes nymphs are a little easier to see than larvae, as they have somewhat darker coloration, but the posterior end of their bodies can still be semi-transparent.  And, as you can surmise from their still tiny size, would hide easily under hair or in areas where you can't see or reach without assistance.  This makes them very problematic, because during its larval blood-meal, a tick can pick up pathogens and is able to spread those pathogens on to its next prey.  The Minnesota Department of Health estimates as many as one in five Ixodes nymphs may be carrying Borrelia burgdorferi, the bacteria responsible for causing Lyme disease.  Because Ixodes nymphs are now potentially capable of spreading disease when they feed, they tend to be less picky about their prey and, if they bite a human, they can be easily overlooked and allowed to feed long enough to increase the risk of pathogen transmission like B. burgdorferi, some sources consider nymphal ticks to be the riskiest stage for bites. 

Ixodes nymph season is typically reported as being mid-May through June and then tapering off in July.  However, peak nymph season may vary depending on weather patterns and geographic location.  Finding nymphs in our active tick collection process is a challenge, because they are so small, and because they tend not to be out questing for food as long in the warm seasons as their adult counterparts.  However, when we find more than adults in a given area year after year, we can conclude that the species has taken hold in that location instead of being accidentally carried in on people or animals as they migrate through on their travels.  When a tick species takes a hold and is seen to be actively reproducing and increasing its population in a new area, this helps us get a picture of how populations change, expand and migrate over time.  Also, this information is crucial to understanding the risk of disease emergence in new regions.

Currently, in northern Minnesota we do not find A. americanum ticks, although there are reports of some being spotted in the southern areas of Minnesota.  While A. americanum and D. variabilis ticks can spread other pathogenic microorganisms to humans and domestic animals, neither are believed to be able to cause Lyme disease by the transmission of B. burgdorferi. 

No matter where you enjoy the great outdoors, the adoption of appropriate protection methods to avoid tick bites and conducting thorough tick checks daily are the best line of defense against the spread of tick-borne diseases.

-C. Fisher

Community Contributors: Now that's a lot of ticks!

It is tick season folks.  And nothing reminds us of this more than all your help reporting on tick activity and collecting specimens.

Earlier this week we received a photo from a Carlton County contributor who sent us this photo:

Photo by E. Felien, June 2020

Each little black speck represents a tick, the whole bunch was collected over the course of a week.  Not all of them are the species responsible for transmitting Lyme disease, Ixodes scapularis (deer ticks), but other species of ticks can also spread various diseases.

So please, when enjoying the great outdoors, protect yourselves from tick bites, and when you do encounter ticks, let us know!

You can self report tick encounters at on our Tick Risk Story Map website (here) and then send us your specimens at: 

University of Minnesota Duluth

Ixodes Outreach Project

1035 University Dr.

Duluth, MN  55812

Attn: SMed 332

When submitting a specimen please include the following information:

Date found

Whether it had been attached to a human or animal or found unattached

Location where the tick was likely picked up

Optional: your name, mailing address and email address for follow up correspondence

Ideally, ticks are best preserved if they are stored in a Ziploc bag or small, airtight container with a dab of hand sanitizer gel to coat the tick.  However, ticks that have dried out can still be useful to our research.  When mailing, please keep in mind that a small baggie can usually be sent without extra postage and handling, however, sending tubes or rigid containers of ticks requires mailing specimens to us in a box to avoid damage.

Should you be interested, we would be happy to send you a Tick Kit with additional information, tick collection and submission information and a tick removal key.  Kindly send your mailing address and we will get a kit out in the mail to you.

Check out our Ixodes Outreach Project Story Map Website:  http://z.umn.edu/Ixodes

-photos and text by C. Fisher

Tick circle of life

To help us better understand the Lyme disease transmission process, we need to study ticks.  This year we have managed to capture a live, fully engorged female Ixodes scapularis tick.  We have been monitoring the process of laying eggs.  A single female can lay as many as 2000 eggs.  Here is a photo of our specimen:

Engorged female Ixodes scapularis laying eggs (ruler in background shows mm markers).  Image by C Fisher, May 20, 2020

We are storing the tick in a brown bottle, which gives everything in our photo an amber-brown color.  The grape-like shape to the left is the engorged female tick, and he eggs are to the right of her head (the eggs have piled up and covered her head).  After laying all the eggs, the female dies.

It took approximately two weeks from the time the tick was caught until eggs began to appear.  Eggs seemed to be laid over the course of several days to a week.  

-C. Fisher, photos by C. Fisher

Remember Fido during peak tick season!

I pulled this slightly engorged female Ixodes scapularis off my dog on Tuesday, May 5th.  It had probably been attached since Sunday when I was out at my partner's farm in Carlton County, Minnesota.  This photo shows us how much a female tick can swell after approximately 36-48 hours of feeding.

 I.scapularis, adult female, slightly engorged

The ruler scale is in cm

This serves as a good reminder that it was time to repeat the dosage of my monthly tick prevention on our dogs.  You should check with your veterinarian to discuss the best method of tick prevention for your pet.  A variety of topical and oral treatments are available.

-C. Fisher, photo by C. Fisher

Passive collection finds a tick in Duluth

An adult male Ixodes scapularis tick was found on the dog of one of our team members on Sunday, April 26th.  The tick had not bitten the dog, it was just walking along the dog's head.

It is possible, but not able to be positively confirmed, that the tick had been picked up while visiting the Lincoln Park area in Duluth, MN earlier in the day on Sunday.

-C. Fisher, photo by C. Fisher