Climate Change Possibly Linked to Spike in Lyme Disease

By Dianne Finch on Tuesday, June 3, 2008.

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Last year we had 892 cases of Lyme Disease in the state – nearly doubling the numbers from 2006.

Some people think that global warming trends are linked to that spike.

NHPR’s Dianne Finch has more.

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Some think may be a link between climate change and tick-borne diseases like Lyme disease. (Centers for Disease Control and Prevention)

Drive north from the southeastern part of the state – you’ll find that bustling cities and seacoast towns give way to lakes and mountains and struggling rural economies.

But landscapes and jobs aren’t the only factors dividing the regions.

According to the latest official numbers, the southeast has the dubious distinction of having higher rates of Lyme Disease.

Jose Montero is the state’s epidemiologist and director of Public Health Services at Department of Health and Human Services.

Montero: “You look at the rates of disease in Rockingham County, Strafford County or Hillsborough County are all quite different from what you will see in Grafton, Sullivan or Cheshire counties. And at same time amount of ticks that you find in those counties is higher and the amount of infected ticks is higher in those three counties or even four if we include Merrimack County.”

Southeastern counties are of course more populated than their northern counterparts.

But that doesn’t explain the higher rates of the tick-borne disease.

There are at least two factors contributing to that difference.

There are more deer per square mile in the southeast – and deer carry ticks infected with Lyme bacteria.

Kent Gustafson is the deer project leader at Fish & Game.

Gustafson: “Obviously the more deer there are the more opportunity there are for ticks to feed and you can wind up with more ticks.”

In addition – deer habitats in the southeast are close to suburban areas – increasing the chance for people to get bitten by the bugs.

The illness can be treated successfully with antibiotics – but if untreated it can lead to serious problems.

Deer might not be the only reason more people contract Lyme in the south.

Paul Epstein is the Associate Director of the Center for Health and Global Environment at Harvard Medical School.

He says that global warming trends are contributing to the spike.

Epstein: “..The envelope in which the Lyme carrying ticks can persist and proliferate and do well is projected to go north with warming and we’re already seeing that this may be affecting tick populations and our best understanding is that warm winters and warm temperatures s at high latitudes could be conducive to a change in the range.”

Epstein added that studies out of Sweden show that ticks are headed north with warming.

State epidemiologist Montero agrees that climate change is a factor – but adds that people can take practical measures to avoid contracting the illness.

He suggests that everyone should conduct “tick checks” after spending time outside – and use insect repellants.

Montero also says people should avoid areas with tall grass.

MONTERO: “Remember that ticks they have survived for a gazillion years because they know how to do their business. So they have over the centuries have figured out if they are in the tallest grasses they have a chance of jumping onto whatever mammal comes around so if that mammal is a dear if that mammal is a human too bad for us but that’s what they do.”

Fish & Game’s Gustafson said that his agency is taking measures to control deer populations – such as encouraging hunters to kill female deer.

But Harvard’s Epstein says that probably won’t be enough.

The bugs also travel on small mammals - such as squirrels and mice.

He says that until the climate is stabilized, diseases such as Lyme will continue to spread.

For NHPR News, I’m Dianne Finch