2017 may be a very bad year for Lyme disease

It started with an unusually large abundance of acorns in the Northeast two years ago.

That fueled a population boom of white-footed mice last year.

And those tiny mice are breakfast, lunch and dinner to ticks, dozens of which can attach themselves to a single rodent, feed on its blood and acquire the bacteria that cause Lyme disease.

Now some scientists are predicting a surge in the number of Lyme-carrying ticks beginning this month and lasting into early summer.

“The risk to humans is going to be high starting this spring,” said Felicia Keesing, a biologist at Bard College in the Hudson Valley, who has spent years researching tick-borne diseases. “We want to get the word out so people can take precautions. Our dream is that we don’t see this translate to human cases.”

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New Jersey health officials said they are monitoring the work of Keesing and other scientists as Lyme disease season gets underway.

Like many Northeast states, New Jersey has long had a high rate of the disease, due in part to residential expansion into tick territory. Ticks must be attached to humans for 36 to 48 hours or more before the Lyme bacteria can be transmitted. If detected early, the disease can be treated successfully with antibiotics. If left untreated, it can lead to serious heart and nervous system problems. Other long-term effects include headaches, chronic stomach problems, memory loss, stiffness of joints and speech impairment.

The most common infected tick in New Jersey — black-legged or deer ticks — will feed on just about any animal they can attach themselves to. And although they are often found on deer, which can transport them around a forest, it’s typically the white-footed mouse that infects ticks. The mice host the bacteria that cause Lyme disease, borrelia burgdorferi. Ticks acquire them by feeding on mouse blood and can then transmit them to other animals and humans.

Cases may already be up, with the relatively mild winter allowing ravenous adult ticks to be more active. Joe Zoltowski, director of the state Division of Plant Industry, found ticks on his clothes in January during his regular treks through New Jersey’s fields and forests.

“It was crazy,” he said. “I’m plucking ticks off me in January. You’re not supposed to see that.”

Ticks have a two-year life cycle, going from larva to nymph to adult.

What concerns Keesing is not the adult ticks, which die off in the spring, but the newly formed nymph ticks that acquired the Lyme disease pathogen when they feasted on mouse blood as larvae last fall. About 30 percent of nymph ticks are infected in a normal year, Keesing said. That is expected to go up.

Keesing and scientists at the non-profit Cary Institute of Ecosystem Studies in upstate New York say there is a direct link between acorn abundance and a surge in infected ticks.

Oak trees go through a boom-and-bust cycle with acorn production, and 2015 was a boom year in the Northeast. With a plentiful food source that can be stored over the winter, the mouse population often swells the following year. “We saw the acorns in 2015 and then we saw a plague of mice in 2016,” Keesing said. “We have 25 years of monitoring that shows the link.”

Although ticks can acquire the bacteria that cause Lyme and other diseases from other animals, the vast majority are infected by mice. Nymph ticks often look to attach themselves to an animal or human beginning in May to feed. But Keesing said rising global temperatures are moving feeding time up by a month. “May has been Lyme disease awareness month, but we may have to change it to April,” she said.

Lyme disease cases sometimes vary wildly from year to year in New Jersey. They surged to 4,855 in 2015 from 3,286 the year before, according to the latest data available. Such a rise is not unprecedented. There were more than 6,000 reported Lyme disease cases in 2008.

State health officials are unsure of what causes the fluctuations. And the numbers may not be accurate, said Tina Tan, the state epidemiologist.

Lyme is often misdiagnosed because it mimics the symptoms — fatigue, muscle pain, joint swelling, fever — of many other diseases. It requires a special blood test.

“We assume that all of our numbers are underreported,” Tan said. “It’s just not being diagnosed correctly in many instances.”

Other biologists say they, too, will be keeping an eye on the Cary Institute’s work this summer as scientists collect nymph ticks from the Hudson Valley and test them for disease.

“There are a lot of factors showing the potential for an increase this year,” said James Occi, a microbiologist at Rutgers New Jersey Medical School who concentrates on tick-borne diseases. “Prophecy can be a tough thing in biology. A lot of people will be looking at this work.”

More Lyme disease information and coverage can be found here. 

Preventing tick bites

• Avoid wooded and brushy areas with high grass and leaf litter, especially April through July. 
• Cover exposed skin during hikes.
• Repel ticks with DEET
• Take a shower immediately after outdoor activities.

Lyme disease cases in New Jersey  

2015: 4,855

2014: 3,286

2013: 3,766

2012: 3,576

2011: 4,262

2010: 3,712 

Lyme Disease symptoms:

-A bullseye shaped rash at the site of the bite that appears about a week later.

-Severe headaches and neck stiffness.

-Arthritis with severe joint pain and swelling, particularly the knees.

-Irregular heart beat. 

-Nerve pain.