Robert Fox’s letter (“Blame the rodents,” April 14) concerning the report of Southold’s tick working group is very useful. It reveals major reasons why it has been so difficult to make progress on our deer-related problems, including the present risk of contracting dangerous tick-borne diseases in our town.
As the letter bears little relationship to what is actually said in the report, it seems obvious that Mr. Fox did not carefully read or understand the latter. It also seeks to perpetuate the myth that simple, workable solutions are being overlooked.
My committee actually made clear that the white-footed mouse is a major reservoir host for the organism causing Lyme disease, while the deer function as the principal reproductive host for the black-legged ticks that transmit the disease. This distinction is critically important. By providing an abundant source of blood for the adult, reproductive stage of both black-legged and lone star ticks, deer have fueled an explosion in tick populations and tick-borne diseases. Even if the mice could be eliminated (which is inconceivable), this would not solve the disease problem. Other mammals also serve as hosts for many of these diseases. In the case of human ehrlichiosis, (a serious tick-borne disease present in our area), deer are thought to be the main reservoir host, and white-footed mice play no essential role in its maintenance or transmission.
Placing Permethrin-treated cotton balls in yards for use as nesting material will detick some mice, but cannot provide a complete solution. This is moderately expensive, not every property owner will not use the strategy, and all mammals that carry the diseases will not use the cotton balls. For example, shrews are reservoir-competent hosts for the Lyme disease organism, abundant in many parts of our town, and less likely to use the cotton balls. As discussed in our report, we are now dealing with multiple tick-transmitted diseases carried by a variety of wild animal hosts.
The story about the supposed efficacy of guinea fowl as tick predators is another myth. These birds are likely to have great difficulty spotting infective tick nymphs (which are tiny), as noted by the authors of the original report. Furthermore, a number of authorities subsequently observed that there is no good evidence that guinea fowl consume sufficient ticks to impact overall tick abundance. Finally, one scientist even raised the possibility that introducing large numbers of an exotic species (i.e. guinea fowl) into the environment may create new disease problems, because the birds themselves can carry large numbers of ticks.
Mr. Fox is correct that it is challenging to reduce deer densities sufficiently to diminish the frequency of tick-borne diseases but, as documented in our report, this has nevertheless been accomplished. While the successes have been rare, the full range of options for humanely reducing excessive deer populations simply are not being used. We should not be making excuses and dithering, when much more productive approaches are being used in adjacent states and upstate New York. The price we pay is that many of us now become very sick or chronically disabled, and some even die, after contracting tick-borne diseases.
Dr. John Rasweiler is a Cutchogue resident and retired medical school professor. He serves on Southold Town’s deer management committee, tick working group and the Suffolk County tick control advisory committee and is also a North Fork Deer Management Alliance board member.