Expert says there is no threat to immunocontraceptive research program.
By: David Campbell
Two of the 20 deer vaccinated under Princeton Township’s experimental immunocontraceptive program have died, Princeton Animal Control Officer Mark Johnson said this week.
One of the tagged and immunized does was hit by a car and killed May 9 in the area of Harrison Street and Prospect Avenue, Mr. Johnson said. Its tag number was 2, designating it the second of the 20 deer immunized in late February and March in the southeastern part of the township.
A second deer, tag number 11, was found dead April 30 on Philip Drive. Mr. Johnson said the animal may have eaten poison put out by a resident to kill rodents, noting that deer have been known to die in this manner in the past.
"I don’t think it was intentional," he said.
But Dr. Larry Katz of Rutgers University’s Department of Animal Sciences, who is overseeing the township experiment, said it is still not clear what the animal died of.
The biologist said the symptoms that led Mr. Johnson to conclude poisoning regurgitation of the animal’s intestinal contents is a byproduct of natural death caused by fermentation, and said the amount of poison needed to kill the animal would have been "immense."
He said the experimental vaccine is safe and would not cause poisoning.
Mr. Johnson said a third immunized deer, tag number 19, was spotted exhibiting injuries that he said could have stemmed from being hit by a car.
But on Tuesday, a Rutgers graduate student monitoring the immunized deer under Dr. Katz determined that the animal was healthy and doing fine. Dr. Katz said a loosened radio collar and the shedding season had resulted in some hair being worn off, showing pink skin, which may have led to the report of injuries.
"As of this afternoon, she was fine and healthy with a little bit of irritation at her neck," Dr. Katz said Tuesday.
When asked whether he thought the killed deer jeopardized the program, the Rutgers biologist said some losses are to be expected in a biological experiment, whether it is in the lab or the wild like the one under way in the township. He said he is not yet concerned, but said he wouldn’t want to see attrition continue at this rate.
"Whenever you design an experiment and you’re looking at how many animals are needed, you always build in the unexpected," Dr. Katz said. "Animals get sick and die. In the wild, they disappear. There’s a variety of things that can go wrong."
The Rutgers biologist said he believes the experiment still has a good group size from which to gather data.
"While you never want to lose any, you always know you’re going to lose some," he said. "It’s the nature of biology, even in a controlled setting."
Thomas Poole, chairman of the township’s Deer Program Evaluation Committee, called the losses "disappointing" but said losses to some degree were not unexpected.
"We anticipated there would be attrition with those that were inoculated," Mr. Poole said. "We’re just going to have to accept this level of mortality, but the analysis will go on."
Anthony DeNicola of White Buffalo, the Connecticut firm that conducted the inoculations using experimental one-shot vaccine SpayVac, was not available for comment this week.
Mr. DeNicola has said he plans to vaccinate between 40 and 50 deer next year as part of the ongoing study.
When the Township Committee approved the $160,930 contract with White Buffalo last December for this year’s deer-management program, Mr. DeNicola estimated the vaccinations, tagging and radio-collaring cost at about $600 per deer, with him donating his labor free of charge.

