Deer Tick Virus May Be On Rise Near the Appalachian Trail

Ticks. In the outdoor community there are few creatures more feared or more despised than the tick. First of all they suck your blood to survive. Next consider that the tick’s favorite past time is to carry and transmit a plethora of disease. Lyme Disease, Rocky Mountain Spotted Fever, and Tickborne Relapsing Fever are just a few of the horrifying names present on the tick’s long list of pathogens. There are even some ticks that cause victims to form an allergic reaction to red meat. As if this were not enough ticks have taken upon themselves the initiative to become even more reviled.

For whatever reason I’ve seen a lot of articles from last year reappearing suddenly regarding a “new” tick virus running rampant through New York and New Jersey. As I was hiking through this section of the trail last year at about the same time these articles were published, and having never even heard of the supposed danger my curiosity was naturally peaked. Was it all just fear mongering or were there legitimate concerns being raised? I decided to delve into what the Internet had to offer and see what all the hubbub was about myself.

According to a study published July 2013 in the scientific journal Parasites and Vectors  it seems that incidents of the lovingly named Deer Tick Virus (DTV) are on the rise in eastern New York. The DTV is a virus that resembles the Powassan Virus (POW) sharing a 94% identical amino acid chain. As a result it’s thought that DTV is a genotype (the genetic makeup of an organism usually referencing a specific trait) of POW. Therefore, DTV is also known as the Powassan Virus Lineage II.  The primary difference between the different lineages of POW is the tick that carries them. POW (Lineage I) is transmitted  by Woodchuck/Groundhog ticks while DTV (Lineage II) is carried by…well…deer ticks. The 2013 study concluded:

Evidence of widespread and continuous (2007–2012) DTV transmission was noted in several counties of the Hudson Valley, NY, concomitant with an apparent increase in the number of diagnosed human POW encephalitis cases since 2004 in the same region.

This information should be of special interest to hikers along the Appalachian Trail. The study found that 43  out of 870 pools of “questing” ticks tested positive for POW/DTV. According to the Center for Disease Control (CDC) a questing tick is any tick lying in wait in for a host to brush up against them so they can hitch a ride and feast. This may not sound like a lot, but 36 of the 43 positive pools were found in Dutchess and Putnam Counties—two counties which the Appalachian Trail passes through in New York.

So do you want the good news or the bad news first?

Let’s just go ahead and get the bad news out of the way.

Bad News

Person’s infected with the virus rarely show early symptoms. Also the incubation period for the virus can range anywhere between one week to one month. If symptoms do show they can include:

• fever
• headache
• vomiting
• weakness
• confusion
• loss of coordination
• speech difficulties
• seizures

The primary danger of the virus is that it infects the central nervous system. This can cause encephalitis and/or meningitis—both of which are bad news. According to the CDC half of those who survive the encephalitis cases have permanent neurological issues. These issues can include recurrent headaches, muscle wasting, and memory problems. It’s estimated that around 10% of the virus infections resulting in encephalitis are fatal.

Lyme Disease is undoubtedly the most well-known tick-born illness. Despite that it’s estimated that 30 – 50% of deer ticks carry the disease many adventurers are able to avoid the infection as Lyme Disease grants hosts a grace period to remove the tick before transmission occurs. It can take 36 hours or more before Lyme Disease can pass from parasite to host. However, POW/DTV isn’t as good a sport as Lyme Disease and can, according to the study, infect the host in as fast as 10 minutes after the bite.

The whopper here is that currently “there are no vaccines or medications to treat or prevent POW virus infection.” Severe cases of the virus often result in hospitalization until the body can fight off the illness.  So in a nutshell POW/DTV is an incredibly unforgiving little bastard.

Good(ish) News

Incidents of the POW/DTV infections are rare. In an interview with Medpage Today co-author of the study Richard S. Ostfeld, PhD stated that:

“the infection prevalence of about 1% to 6% among these ticks is low compared with Lyme disease, which often is found in 30% to 50% of ticks…”

Depending on how you look at it that still boils down to anywhere between a 1 in 100 to 1 in 20 shot of you running into a tick carrying the virus. You should also note that cases that result in encephalitis may actually be rare. Co-author Alan P. Dupuis, PhD also told Medpage Today that:

“…we’re probably only seeing the most severe cases. There could be many milder cases of flu-like illness that resolve on their own…”

Also this is only one study. Their methods were sound but I’d say its safe to take it with a grain of salt. It takes repeatable results for science to work. The main thing this study encourages is that more studies are needed to better assess the threat DTV and POW pose to humans.

So what should you take away from all this?

Simply the awareness that POW/DTV is out there. It’s not something I had ever heard of before leaving for the trail, so I doubt it’s a stretch that many of you haven’t heard of it either. Yet, the question of the hour is if it’s something you really need to worry about on the trail.

Probably not.

Infection is possible but definitely not probable. Severe incidents appear to be on the rise but the cases per year are still small. Even so on the AT you’re only going to find yourself in this part of New York for a few days to a week at most. Despite the fact that you most likely won’t have to worry about dealing with POW/DTV it’s a good idea to know that it exists. Because of the rarity of the virus many doctors and physicians may not think to test for the virus as a cause for certain symptoms. Knowledge is power, right?

If nothing else this should just be further encouragement to do those annoying tick checks. As with all tick-born illnesses prevention is the best defense against this virus. This is where I would normally recommend wearing long sleeves and pants in these tick-dense areas, but I still remember hiking through New York in the heavy, humid summer heat. I wouldn’t wish sleeves upon my worst enemy in that kind of weather.

For me the only thing that ever seemed to be effective as a bug spray were DEET heavy products, but that was actually more of a reaction for fighting mosquitoes than ticks. Those flying demons caused me more mental and physical duress on the trail than ticks ever did. Also yeah…chemicals and what not. So pursue whatever prevention methods you think will work best for you. Do tick checks every night, and maybe even when you’re taking short breaks during the day. It doesn’t take that long and it could save you a world of discomfort.

The intention of this article is to help spread awareness of a possible threat to hikers on the trail, especially as we find ourselves on the cusp of tick season. This article is more or less a summary of the papers/articles I read and a rehash of information discovered by people much more qualified to talk on the subject than myself. If you want to read more in-depth information from the real scientists who studied the virus follow the links below. I highly recommend doing this if you want to be truly informed.

• Center for Disease Control – Powassan Virus
• Medpage Today – Deadly Deer Tick Virus on Rise in New York State
• N.J. officials alert medical community about fatality from tick-borne illness
• USGS Powassan Virus Disease Maps 2013
• Isolation of deer tick virus (Powassan virus, lineage II) from Ixodes scapularis and detection of antibody in vertebrate hosts sampled in the Hudson Valley, New York State
• Potential Role of Deer Tick Virus in Powassan Encephalitis Cases in Lyme Disease–endemic Areas of New York, USA

Photo Courtesy of the U.S. Department of Agriculture