On behalf of the Martha’s Vineyard tick-borne illness reduction initiative, we would like to respond to the letter from Laura Hagen that appeared in last Friday’s paper. Ms. Hagen continues to try to refute the utility of deer reduction as a management tool for reducing the risk of Lyme disease, and as usual mixes some truths (deer do not infect ticks, mice and other small animals do) with semi-truths and comments from “authorities.” Her letter, however, explicitly demonstrates that she accepts the critical role of deer in the reproduction of the deer tick by recommending the use of insecticides applied to deer (via the four-poster system). Use of deer-targeted insecticide systems can reduce deer ticks and Lone Star ticks by as much as 80 per cent where they are applied, although as with most products, mileage may vary. When the use of that control method is curtailed, for example due to lack of funds, the ticks return to their pre-intervention numbers within a year or two. Along with the majority of published deer reduction studies that demonstrate a similar effect on ticks, these ecological experiments clearly prove the link between deer ticks (and Lone Star ticks) and deer.

The purpose of deer reduction is not for immediately reducing tick-borne disease case numbers, nor does anyone advocate using just deer reduction to achieve this. We need to continue to do our everyday, short term (band-aid) interventions such as the use of repellents, tick checks, permethrin treated clothing, habitat management, and careful use of insecticides while we seek a longer-term solution. There are three factors that were at least seven decades in the making that created the problem that we have today:

• We chopped down the forests and let them come back as very different, unbalanced ecosystems;

• We use the new forests very intensively by having our homes — increasingly too many of them — right in among the trees;

• And we have failed to effectively manage deer in the absence of their natural predators, at least in the sites where tick-borne disease is a problem.

Of these three big-picture factors, only deer can be targeted. It is the only way to restore the Vineyard to what it was like before the 1960s, when kids could play in their yards and only come up with dog ticks (which, fortunately, are less likely to cause a tick borne infection . . . but no tick is a good tick). We can’t chop the trees down again nor can we prevent people from having the forest around their homes, nor keep them from enjoying hikes and berry picking and everything else that is good about forests. If we bring deer numbers back to a level that is within their biological and cultural carrying capacity (tenfold less than they are now), then the ticks will also be reduced. Not eliminated, but reduced so that instead of getting a deer tick bite every day, one gets a deer tick bite every 10 days. That will translate to fewer cases of Lyme disease. Restore the risk landscape back to what it was like before deer ticks were a problem— there is no coincidence that that was a time when seeing deer was not commonplace. Deer reduction (and maintaining the numbers at a low level) is not an overnight solution but one that will help our children and our children’s children.

Four posters and Damminix tick tubes can work, but they are an expensive monkey on the back of a community. You would need to fund and deploy them every year, forevermore. Deer reduction is free and a small herd can be maintained through the years with little effort or expense. There is other value added to a community with fewer deer, such as greater plant diversity, fewer mosquitoes (deer serve as the main blood source for all of our common human biting species) and greenheads, and fewer automobile collisions. The deer herds on the Vineyard and in many other communities need to be reduced. It is an ugly fact that we need to accept.

This letter was also authored by Michael Loberg, Matt Poole and Richard Johnson.