This year’s deer hunting season has begun, and many options are being considered for how to lessen the impact of the continuing infestation of deer ticks on Martha’s Vineyard.
Deer ticks are responsible for transmission of three of the known major illnesses borne by these arachnids: Lyme disease, babesia and anaplasmosis. Recent stories in the Gazette have focused on the invasion of our Island by increasing numbers of lone star ticks, which host other equally life-threatening diseases.
The medical crisis presented by deer ticks and lone star ticks remains an important issue and one that cannot be ignored. How to best tackle the problem is being pursued and discussed in earnest. Legitimate questions often posed include why the deer? What happens if the vector then changes to ticks jumping onto turkeys, raccoons, chipmunks, or other mammalian species. Why not focus on the white-footed mouse population. Why not wait and embrace the project involving genetically modified mice bred to be immune to Lyme disease (this may happen in seven or more years time).
Other questions center on which model will be chosen to know how many additional deer need to be culled per year.
These valid questions draw attention to the fact that the actual number of cases of Lyme disease, babesia and anaplasmosis cannot be precisely ascertained. The actual size of the deer herd also cannot be accurately measured, and the extent of the spread of these tick–borne diseases via other smaller animal species can only be approximated. Lastly, it is difficult to model the actual effects of reducing the size of the deer herd on Martha’s Vineyard and how much effect this reduction will have on lowering the number of ticks carrying these potentially lethal diseases.
As has been pointed out in several articles written by Dick Johnson, the Island’s leading expert on all varieties of ticks who among other things has extensively studied the life cycle of deer ticks, we will not have the luxury of time to assemble and study the answers to these issues. I concur with this view. No matter how valid these questions are, we will never have the answers to all of them.
We must keep the focus on the current issues presented by ticks and their associated debilitating diseases. Let’s go with the best possible solution. The common sense response is to just get on with a deer herd reduction program.
Another major public health concern has also recently been identified: the transmission of babesia and anaplasmosis by blood transfusion. All blood in our neighboring state of Rhode Island, and some blood (if requested) in Massachusetts is being screened for the presence of babesia.
Important studies supporting deer herd reduction have recently been published by Dr Kirby Stafford, chief scientist and state entomologist for Connecticut. These studies show that significant reductions in the deer herd strongly correlate with a reduction in number of deer ticks and the number of recorded cases of tick-borne diseases. Thus reducing the deer herd — the larger animals that are essential in the life cycle of the deer tick and other ticks — offers the greatest chance for reducing the incidence of these diseases. There are estimates of approximately 4,000 to 5,000 deer on Martha’s Vineyard, representing a population of upwards of 40 to 50 deer per square mile of wooded habitat.
The dense population of deer also adds to the spread of Lyme disease in Island pets, farm animals and horses, and of course the number of motor vehicle accidents. All the scientific publications, including the recent paper by Dr Stafford, emphasize that to be an effective remedy, the deer population needs to be drastically reduced to between eight to 10 deer per square mile, since the effects on the number of deer ticks is not linear with the number of deer removed. As alarming and unwelcome as this target may sound, these are the facts based on the best science available.
From my perspective, the community should support a plan that has the greatest possibility of success. Waiting and thinking that there may be alternative solutions down the road is just not an option. We need to act now and offer our support to the boards of health, to Dick Johnson and others, and do what is best for our community.
The recent program by the Island Grown Initiative to accept deer from the hunters and process and distribute meat to the elderly and the Island Food Pantry is a noble cause. The plans to have an additional refrigerated storage facility, centrally located, at the Agricultural Hall will also be beneficial to the hunters.
Mr. Johnson and others are investigating making more private property available to hunters by soliciting the cooperation of property owners.
It will take some time for state and town authorities to piece together other practical solutions with the all-Island boards of health. Meanwhile, with the start of the hunting season, we should do all we can to encourage our local hunters to help solve this serious medical issue by increasing, wherever possible, the number of deer taken.
Dr. David J. Morris, is emeritus professor of pathology and laboratory medicine at Alpert Brown University School of Medicine. He is a longtime homeowner in Vineyard Haven.
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