New York State IPM Program

October 5, 2017
by Matt Frye
Comments Off on Lyme Disease by the Numbers

Lyme Disease by the Numbers

By now, you’ve heard of Lyme disease. If you’re reading this in the Northeast, chances are you’ve had Lyme disease or know someone that does. And perhaps you know that Lyme disease is a topic entrenched in scientific and political controversy in terms of accurate diagnosis, effective treatment, and access to insurance. Putting these larger issues aside for the moment, the intent of this post is to present data on Lyme disease and help people to better understand the risks.

What: Lyme disease is a series of symptoms that occur when our body is infected with a bacterium called Borrelia burgdorferi. In the Northeast, the only way that people and animals become infected with Lyme is when they are bitten by a blacklegged tick – sometimes called the deer tick. The complex lifecycle of the tick and how they obtain and transmit pathogens is described by TickEncounter.

Boys aged 5-9 years old have the highest confirmed number of Lyme Disease cases (Source: CDC)

Who: Each year, approximately 30,000 cases of Lyme disease are reported to the CDC, making it the most commonly reported vector-borne disease in the US [a vector-borne disease is one transmitted through the bite of an organism such as a tick, mosquito, flea, etc.]. However, studies suggest that this number is only a fraction (about 10%) of the actual cases of Lyme disease in the US, putting the estimated number of cases between 300,000 and 400,000 each year. Based on this value, Lyme disease is the second most common infectious disease in the US, falling between two sexually transmitted diseases: Chlamydia (#1) and Gonorrhea (#3). Who is at the greatest risk of Lyme disease? Children! Especially boys aged 5 to 9 years old. Parents – check your children daily for ticks!!

Most cases of Lyme disease occur in the summer after being bitten by a spring-time nymph tick (Source: CDC)

When: Ticks can be active any day of the year when temperatures are above freezing. However, based on their lifecycle, the greatest risk of acquiring Lyme disease occurs during the spring months when nymph ticks are present, resulting in summer-time symptoms and doctor visits. Nymph ticks are about the size of a poppy seed, which makes them difficult to see. Check yourself daily for ticks, using your fingers to feel raised bumps and your eyes to notice new black marks. 

Where: While Lyme disease is regarded as the second most common infectious disease in the entire US, over 96% of all cases come from only 14 states.

Fortunately, there are steps that individuals can take to reduce their risk of encountering ticks and acquiring tick-borne disease. These topics will be covered in a subsequent post.

Distribution of Lyme Disease cases in North America (Source: CDC)

Darker colors represent higher incidence of disease (Source: NYS Dept. of Health)

February 24, 2016
by Mary M. Woodsen
Comments Off on Every Season Is Tick Season

Every Season Is Tick Season

At IPM we call it the black-legged tick because that’s its true name. Yet most people in North America — perhaps even you, dear reader — call it the deer tick. A name with curious stories to tell.

But first the commercial: every season is tick season. Impervious to all but the most bitter cold, ticks take shelter in the leaf litter in gardens and woods. Whenever it gets a little above freezing, they crawl out and up. Any adults that failed to find a host earlier in winter or fall scramble into knee-high vegetation. (Females need a blood meal before they can lay eggs.) There they wait patiently for some critter to brush against whatever stalk they’re clinging to, and when it does — they grab hold.

Courtesy of TickEncounter at the University of Rhode Island, this image shows all the life-cycle info you need to know.

Courtesy of TickEncounter at the University of Rhode Island, this image shows all the life-cycle info you need to know.

Even during this fickle February of 2016, when many places south of the Adirondacks have repeatedly lost their snow cover, leaving the barren ground to freeze hard, those ticks keep ticking along. Yes, many die. But many remain. On lovely sunshiny days when you wander outside to shake off a bout of cabin fever, be sure to dress right to keep ticks off you.

And having done that, relentlessly check yourself for ticks when you get inside.

Now back to our story. That name — deer tick — suggests that deer carry Lyme disease. If you’ve had a bout with Lyme or any of the less-than-pleasant co-infections that black-legged ticks also vector, just thinking of Bambi could give you the chills. But while deer assuredly spread ticks far and wide, they don’t vector Lyme. Which means a tick that is Lyme-free won’t pick up the Lyme pathogen from a deer.

The buck stops there.

Verdant summer meadows? Come winter, the ticks are still there.

Verdant summer meadows? Stay vigilant. It’s too easy to pick up tiny, hard to see nymphs  — ones already vectoring Lyme.

The critters that most commonly carry Lyme disease — notably mice, but also shrews and chipmunks — assuredly do get Lyme disease. But odd as it seems, it doesn’t knock them out. Instead they just keep chugging along, doing their mouse or shrew or chipmunk thing. Which includes transmitting the Lyme pathogen to ticks throughout their life cycle. Ticks that grow larger and larger. Ticks that eventually — instead of hanging out low to the ground where the mice are — become large enough to scramble into knee-high vegetation where they’re yet more likely to land on some hapless human. Or dog, raccoon, fox, coyote, skunk, cat, sheep, a ground-nesting bird, cow, horse … the list goes on.

Some, like deer and probably other wild animals, don’t get particularly ill — though it’s not been closely studied. But dogs, horses, and humans (less likely, cats) can get knocked for a loop. Even so, we likewise don’t transmit Lyme; the tick would already need to be infected. The buck stops there.

The next commercial: about that tick that snuck aboard during your post-lunch walk in the curiously warm February sun … you might not have as much time to deal with it as once was thought. Sure, in some cases it’ll be 24 to 48 hours before that tick starts transmitting Lyme. And not every tick carries Lyme or other diseases.

But still, better safe than sorry. Because recent research suggests: as you sit down to dinner that tick might already be dining too, but with consequences you don’t want to bear. Knowing that, relentlessly check yourself for ticks when you get inside. And even if you don’t care for school grounds or a summer camp, this IPM fact sheet is rich with useful information.

Many thanks to Rick Ostfeld (Senior Scientist, Cary Institute of Ecosystem Studies) and Joellen Lampman (Turfgrass Specialist, NYS IPM).

Skip to toolbar