Ticks & Their Mysterious Microbes

Borrelia burgdorferi by NIAID (2011) CC BY 2.0 via Flickr. https://www.flickr.com/photos/niaid/5661846104/
Borrelia burgdorferi by NIAID (2011) CC BY 2.0 via Flickr.
https://www.flickr.com/photos/niaid/5661846104/

While I’m browsing Facebook, I sometimes glance at the topics in the “Trending” column in the upper right hand corner of the homepage. While they are usually related to celebrity gossip or disasters of some kind, today I was intrigued a geographically relevant piece of click-bait: “Powassan virus: Rare Virus Spread by Ticks Found in Southern Connecticut.”

As an environmental educator in the woods of Connecticut, I have encountered my share of ticks – those shameless, blood-sucking arthropods that are carriers for a veritable zoo of exotic microbes. Our usual practice to avoid ticks was to wear long sleeves and long pants, tuck pants into socks (aka “cool pants” or “forest pants”), and do nightly tick checks before going to sleep. If we did locate a tick (or one of our students did), there was often a panicked rush to the medic to remove the critter in an appropriate and safe manner.

Our primary concern with tick bites was the transmission of Lyme disease (caused by the spirochete Borrelia burgdorferi). When I was an Adamahnik farmer in the Spring of 2013, I was pretty sick with symptoms that presented as extreme fatigue, fever and joint pain. When I went to the local ER, they ran a test for Lyme, which came back as negative. However, the doctor explained, due to the high prevalence of Lyme in the area and high rate of false negatives for the lab test, they were still going to put me on a 2 week course of antibiotics (doxycycline).

At the time, I think the side effects from the doxy made me feel sicker than I did initially! I was still sick a week later (when antibiotics should have started to have some effect), so I went back for additional testing. Those blood tests also came back negative, and the doctor discontinued antibiotics. I was still pretty tired, but eventually started feeling better.

I can’t say if I had Lyme or one its tick-bite-transmitted fellow travelers (also treated with doxycycline) or an even more mundane human-transmitted bug. I am really, really glad I eventually got over it.

The presence of emerging tick-borne viral infections such as Powassan virus strikes fear into the hearts of campers, educators and parents (not to mention the “ick” factor associated with being bitten by creepy-crawly critters.) You can’t treat them with doxy – medical treatment for this potentially fatal virus is limited to supportive therapy such as IV fluids and respiratory ventilators. There are also potential neurological side-effects of the virus.

Before panic sets in, it is helpful for me to remember a few things: “Emerging” doesn’t mean that the viruses are particularly new – they’re just new to being detected by science. Lyme Disease was described as a distinct disease in 1976 when doctors identified a cluster of kids with arthritis symptoms around Old Lyme, Connecticut. Borrelia burgdorferi, a spirochete shaped kind of bacteria, was identified as the infectious agent in 1981. Modern DNA analysis on ticks gathered in the 19th and 20th indicated infection with B. burgdorferi, and it is likely that the bacteria has been around in ticks and their bitees for thousands of years (Steere, Coburn & Glickstein (2004)).

The oldest known human infection with Lyme is Otzi the Iceman, a 5300 year old mummy discovered in the Alps. Scientists have detected bacteria of Borrelia sp. in a 15 million year old tick fossilized in amber.

Emerging tick-borne infections are not limited to the Northeast US. Back home in KS, a Bourbon County farmer came down with a mysterious virus, which later turned out to be an exotic-sounding Thogoto virus new to science, which researchers linked to ticks.

The Cary Insitute of Ecosystem Studies in Millbrook, NY studies the ecology of emerging infectious disease. Climate change and human land use changes all impact ticks, their microbes and other hosts, than can affect the spread of these diseases to humans. Check out their resource section for fascinating information on the ecology of tick-borne diseases!

For now, I’m tucking my pants into my socks.

Tangents for this post:

The History of Arthropod-borne Human Diseases in South Carolina (I know it’s not CT, but it’s still fascinating.)

The Outdoors Hates You (Wired Magazine, 2012)

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