Expanding Tick Populations and Lyme Disease

Until two years ago, I never found a tick in my yard. Now with Buffy being blind, she mostly stays on the grass and hardly walks into the shrubby areas, so I was shocked when I saw a tick on her. I found another one on me after I had walked her around my residential neighborhood. Maybe I had brushed against some shrubs near the sidewalk. But these areas never had ticks before. What gives?

I work as an environmental consultant and often am outside in natural areas, so I’m very used to checking for ticks after being out in the woods—but ticks in my yard? I live in a residential area in a small city. I have an extra lot, with a mowed lawn, trees, native plants and ground covers. Yeah, there’s probably some mice and the occasional raccoon or opossum, but  my yard has a fence, so I don’t get too many wild critters.

Last week, I heard a lecture on how ticks and tick-borne illness are spreading rapidly due to climate change. Lyme disease, which was non-existent in my county, has become common in the last few years.  One health department employee said that he expects cases of Lyme disease to rise significantly.

Maybe I should think about retiring before I get sick. Should I risk it a few more years?

Dogs are exposed a lot more than we are since they walk in tall grasses and brush up against shrubs all the time. But there are tick preventatives for dogs. What about for us?

If we stay to the middle of the gravel trail, we’re safe right? Wrong. Ticks crawl around a lot and often will crawl off your dog onto you. Or they can fall out of trees onto you, or when you brush against the shrubs or step on the grass to pick up your dog’s poop.

Ask around. How many people do you know who have had, or know someone who has Lyme disease? I know several people from work. It’s becoming much more common.

What is Lyme disease and why should I be worried about it?

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to people through deer ticks.

• Ticks take 24 to 36 hours to spread the bacteria to your blood. Remove them early.
• Most tick bites do not lead to Lyme disease (Medline Plus)
• Deer tick nymphs can be the size of a pinhead and almost impossible to see.

Symptoms may occur a week or many weeks later can include fever, headache, fatigue, and a characteristic skin rash called erythema migrans (the bullseye rash). Many symptoms resemble the flu, so most people don’t get tested for Lyme disease unless they tell their doctor about a tick bite or have the skin rash. Not everyone gets the skin rash.

Sometimes the only symptoms  occur many months later as listed by the Center for Disease Control:

• Severe headaches and neck stiffness
• Additional EM rashes on other areas of the body
• Arthritis with severe joint pain and swelling, particularly the knees and other large joints.
• Facial palsy (loss of muscle tone or droop on one or both sides of the face)
• Intermittent pain in tendons, muscles, joints, and bones
• Heart palpitations or an irregular heartbeat
• Episodes of dizziness or shortness of breath
• Inflammation of the brain and spinal cord
• Nerve pain
• Shooting pains, numbness, or tingling in the hands or feet
• Problems with short-term memory

Early treatment with antibiotics is the best method to treat Lyme disease. But because the symptoms are often vague and sometimes long delayed, doctors often don’t test for Lyme disease or people don’t seek timely treatment.

If you were exposed to the bacteria, it will remain in your system even if you are asymptomatic. This can make diagnosing and treating the disease a challenge.

Ticks and Climate Change

Lyme disease cases have more than doubled since the 1990s. Most of the cases for Lyme disease occur in fourteen states in the Northeast, upper Midwest, and mid-Atlantic. The number of counties listed at high-risk for Lyme disease has since increased by 320%.

Lyme disease now occurs in the southeastern states. Climate change and our current governmental policies will likely allow this disease to expand.

It’s predicted that by 2050, 12% of the U.S. population may be infected by Lyme disease. Many of these cases will be chronic and this is likely to cause a huge healthcare financial burden–$4.8 – 9.6 billion in 2018 in the U.S—even higher in Europe.

How climate change is affecting deer ticks

• Temperature affects where deer ticks live. Longer lasting warm seasons cause ticks to be active for longer periods and they can survive farther north.
• Warmer temperatures shorten the time to maturity for ticks. One study showed that tick reproduction can increase by a factor of two in the US and by a factor of five in Canada.
• Higher humidity caused by increasing greenhouse gases is affecting deer ticks. Deer ticks may survive longer under highly humid conditions (85 – 95%).
• Mice that carry Lyme disease feed on acorns. Acorns periodically have bumper crops, and when that happens, there are more white-footed mice. More infected ticks were found for up to two years after a year of plentiful acorns

Other factors:

Removing farmlands and re-foresting areas allows ticks to flourish. Ticks survive where deer populations thrive since deer are important hosts for the bacteria. Deer populations are exploding in many areas due to the lack of predators.

 

Leaf litter prevents ticks from dehydrating. Forests have lots of leaf litter which also increases the tick population. Now that I know this, I should clear out my leaves in my shrub beds a lot sooner and better!

What can you do?

Staying indoors is not a realistic option for most of us, and still, we can get ticks that climb off our dogs and onto us. When I camp, my dog sleeps in my tent next to me and often ticks crawl on me in the middle of the night.

Typical recommendations include being cautious when you walk in tall grass or forested areas by doing the following:

• Roll your socks up over your pants so ticks will stay on your pants and you can find them.
• Wear light-colored clothes so you can see ticks.
• Spray yourself with insect repellant (although I haven’t found this to work so well with ticks).
• Wear a hat so ticks don’t get in your hair.
• When you come inside from tick-infested areas, put your clothes in the dryer for about 10 minutes on high—this will dry out the ticks and kill them. It’s even better than washing your clothes.
• Take a shower within a few hours of being inside.
  • Use a washcloth when showering so you can scrub off any ticks—especially the ones you can’t see.
• If you find one embedded in your skin, use tweezers to remove it promptly. Keep the tick in a baggie and freeze it. You may need it to have your doctor test it for the bacteria if you develop symptoms.

For more information, I used this article for a lot of my information http://www.climatecentral.org/gallery/graphics/climate-changes-role-in-tick-migration

I also plan to read this book: Lyme: The First Epidemic of Climate Change. This review made it sound really good.

Next week I’ll talk about some of the controversies over using pesticides for ticks and Lyme vaccines for your dog.