Kentucky has the fastest growing lyme disease outbreak in the US, insurance data suggests

Kentucky has the fastest growing Lyme disease outbreak in America, insurance claims data suggests — as experts warn global warming is allowing more aggressive northern ticks to advance into southern and midwestern states. 

Statistics showed Kentucky was recording 10 claims per 100,000 people in 2021, up from just five in 2016 — a doubling in five years. West Virginia, Idaho, Ohio and Nebraska each also saw claims surge more than 60 percent over the same period.

Experts warn that higher seasonal temperatures have opened up new habitats for ticks in more mountainous areas, which may be fueling the rise in cases.

But they also say that surging awareness of the ‘invisible disease’ thanks to high-profile cases in celebrities including singer Shania Twain and socialite Yolanda Hadid has led many more people to go to doctors whenever they were bitten by a tick — even if they do not have the disease — leading to a concurrent rise in claims.

Dr Jonathan Oliver, a tick expert at the University of Minnesota, warned DailyMail.com that expanding forest cover in some areas coupled with a larger deer population could also be helping the black-legged or deer tick — which can carry Lyme disease — expand its range out of the eastern United States. 

He said the uptick in Idaho was an ‘anomaly’, and likely due to more people catching the disease on holiday in other states including nearby California, Oregon and Washington and then returning home.

Insurance claims for Lyme disease in the U.S. were lower in 2021 and 2020 than in the four years beforehand. But this drop was likely down to the COVID-19 pandemic, leading to people being less likely to go outside or attend hospitals to seek medical care for fear of catching the virus. 

New Jersey, New York and Massachusetts — in the ticks normal range — had the most claims for Lyme disease in 2021. Experts said claims are so high there because ticks in the region are more likely to carry the illness and there is a higher density of people, raising the risk of someone being bitten.

Dr Jon Oliver (pictured), an entomologist at the University of Minnesota, warned climate change may be behind the uptick in claims. But he said it could also be down to changing land use, with more forested areas appearing and there being a larger deer population — the ticks main source of food. Pictured left is a black-legged tick, which may carry Lyme disease

The data was gathered FAIR Health — which owns one of America’s largest claims databases — and was presented on the Johns Hopkins tick dashboard.

Lyme disease is the most common tick-borne illness in the United States with the Centers for Disease Control and Prevention (CDC) estimating 460,000 cases each year, with the critters picking up the bacteria when they bite host animals including deer and mice. They then spread it to humans when they latch on.

Infected people normally suffer a ‘bull’s-eye’ shaped rash around the bite three to 30 days later, and if left untreated may go on to face severe headaches, intermittent muscle pains and — in rare cases — muscle weakness in the face leading one side to droop or facial palsy.

When cases are diagnosed patients are normally offered antibiotics to clear the infection. But in some cases diagnostic tests are done too early, which may leave a patient unable to access proper care for months and risking serious damage.

DailyMail.com added the monthly rates of claims for the disease published by FAIR Health to give a yearly rate, and then compared the figures for the past six years.

It showed Kentucky had the fastest growing outbreak in the country last year, but in West Virginia insurance claims also nearly doubled from 54 to 108 per 100,000 people.

Idaho recorded the third biggest rise up 84 percent in half a decade (from five to nine per 100,000), while in Ohio they rose by 62 percent (from 21 to 35) and in Nebraska they rose by 60 percent (from five to eight).

Both Hawaii and South Dakota recorded insurance claims for Lyme disease in 2021, but none in 2016. 

Lyme disease is normally carried by the black-legged tick from northern states, which feeds on deer — hosts for the bacteria causing the disease — and are more aggressive, making them more likely to bite humans.

But in southern states the local ticks there feed mostly on lizards — which do not carry Lyme disease — and are much less likely to bite humans.

Oliver — who is currently undergoing research into why northern and southern deer ticks behave differently — told DailyMail.com that more humid areas in southern and midwestern states may be behind the uptick.

‘Certainly, it is climate change in northern areas — especially Canada — driving the spread of Lyme disease, but ticks tend to be more limited by humidity.

‘In [southern and western areas] humidity may be affecting their ability to survive, but a lot comes down to land use changes — so as ticks require high humidity to survive they thus they need fairly dense forest places where there is leaf litter where they can find a moist enough area to retreat to.

‘The host animal is also really important, as humans are accidental hosts and most ticks will not be able to survive just feeding on humans. Deer are really important for this so, if there are more deer, expect to see a lot more ticks.’

Data from the U.S. Department of Agriculture shows forest cover has been rising in the south — a region including Kentucky, Virginia and West Virginia — since at least 1997, with another 14 million acres added by 2012.

Estimates suggest deer populations have risen in recent years to number 33.5 million in 2017. However, this was still below the peak in 2000 of some 38 million of the animals. 

Environment officials in Kentucky estimate its deer population has surged a tenth above the average, to 933,089 animals in 2021 compared to 821,608 on average for the last ten years. 

In West Virginia, the deer harvest rose seven percent last year to 106,000 animals compared to the year before — but this was below the five-year average of 113,000 deer.

Dr Reddy Palli, a state entomologist at the University of Kentucky, warned the rise in his state was likely down to more people going to doctors whenever they had a tick bite fearing Lyme disease.

‘A lot of the public is concerned about Lyme disease and that is the main reason they go to the doctor when they are bitten by a tick.

‘[But] the detection of Lyme disease based on CDC guidance involves sending swabs for testing, and I don’t think most physicians do that because it is expensive and more work for them. So… many things are lumped into Lyme disease.’

He said that monitoring of ticks in the state showed more than 90 percent of those present were not black-legged ticks that could carry Lyme disease.

Palli also warned climate change was likely allowing ticks to spread, raising the risk of catching Lyme disease. He said it was making more areas in mountains — such as those in West Virginia — hospitable to ticks. 

FAIR Health and Johns Hopkins did not respond to DailyMail.com’s queries on whether the data contained cases that were not confirmed to be Lyme disease.

The above map shows the 11 states where Lyme disease cases rose in 2021 compared to five years earlier, they are mostly in southern areas thanks to the tick’s expanding range. There was also a rise in Idaho, but experts said this was an anomaly likely sparked by more people returning from neighboring states with the infection. The states are colored by percentage increase in cases compared to five years earlier

The above map shows the rate of insurance claims per 100,000 people for Lyme disease across each state. Claims are highest in the Eastern United States, where ticks are more likely to carry the disease and people live in higher numbers

On Idaho, Oliver said the results were ‘an anomaly’ that may be driven by travel to other states.

He told DailyMail.com: ‘The state has a very low population, which means that any change can look like a big increase — even though the actual amount of cases is still very low.

‘I think this could reflect an increase in travel. The western black-legged tick is in California, Oregon and Washington and it can transmit Lyme disease. It is definitely not found in Idaho, however, but people could be catching Lyme disease in these states and then bringing it back.’

The statistics showed that New Jersey is currently America’s hotspot for Lyme disease insurance claims — with 300 per 100,000 people, followed by New York at 245 and Massachusetts at 214.

Oliver said these states had such high levels before their climates were more friendly to ticks, and because more ticks in these areas tend to carry Lyme disease.

‘In some places in the East like Long Island and parts of New Jersey you get numbers where half of adult ticks are infected with Lyme Disease. This is surprisingly high compared against areas like Minnesota, but typically say about a third of adults have the bacteria and about a quarter of nymphs do. 

‘Basically, you just have really high levels circulating between ticks and rodents in those locations. And you have higher densities of people — leading to more cases and then insurance claims.’

It comes after data from FAIR Health also showed up to four times more Americans are catching Lyme disease now than a decade-and-a-half ago, in another sign the illness is growing in the country.

Analysis revealed a 357 percent surge in applications linked to the tick-borne illness from 2007 to 2021 across rural areas. But there was also an uptick in towns and cities, where it rose by 65 percent over the same period.

Experts warned more people were catching Lyme disease more than ever before across the United States. But the uptick may also be driven by surging awareness of the ‘invisible disease’, thanks to high-profile cases in celebrities including singer Shania Twain and socialite Yolanda Hadid.

People who said they had recovered from the disease called on Americans to ‘take this seriously’, adding that it could leave them suffering symptoms for years.