Do you know where you were on this date, forty years ago? I do. I was a young, senior zoo keeper hired the previous fall as one of the original keepers for the new Metro Toronto Zoo. According to my diary entry for March 13th, 1974, I was helping TB test 17 white-tailed deer. The operation was part of a bigger challenge that began on 8 January 1974 when a female blackbuck antelope died of tuberculosis (TB) in our outdoor holding facility. This began a long-running quarantine and numerous TB tests of the animals – and of the keepers, since TB is one of the many zoonotic diseases that can be passed between animals and humans.
The Tuberculin skin tests that I saw used consisted of an intradermal injection of a tiny amount of purified culture filtrate of Bovine TB under the skin in such a manner that a pea-sized bump was produced. After 2-days, the vet would need to inspect the site of the injection to see what, if any, reaction had occurred. If the test was positive, we would see what appeared to be an allergic reaction – redness and marked swelling – at the site of the injection. In hoofed stock, finding a bare patch of skin can be a challenge. In most cases, the veterinarians preferred the bare patch of skin under the tail around the anus, an area known as the Caudal Fold. A test in this area was not visible unless the animal was caught a second time to have the tail raised for a visual inspection. Another site for testing was in the skin of the upper eyelid. This method was almost always used in primates, and on a few occasions in hoofed stock. The results of the eyelid test were obvious without a second capture. One of the challenges is that a positive reaction does not necessarily mean they have TB, just that they have been exposed to it and have antibodies in their system. Diagnosis based on these clinical signs alone is very difficult, even in advanced cases.
All of the animals in the areas that had housed the blackbuck had to be tested, so on Monday, March 4th, 1974, we began the testing with a male wapiti (elk) and a male roe deer. The following day we caught and tested four reindeer, two muntjac, and seven Chinese water deer. All of these animals tested negative when they were caught-up two days later. The next Monday, on March 11th, we tested seven yak, three tahr, and one male barasinga deer. The female barasinga, according to my notes, was not tested because “the dart glanced off front knee” – meaning she did not go down. The following day we tested ten white-tailed deer and the female barasinga deer and on Wednesday, we tested seventeen more white-tailed deer.
The method of catching and restraining these animals varied. The larger and the more “flighty” animals were shot with tranquilizer darts. Some of the animals could be cornered and physically grabbed and restrained while others were caught in large hoop-nets. Of the ten deer we caught on Tuesday, for example, my notes say we caught two by hand, four in nets, and four of them were tranquilized. These procedures did not always go as planned. One of the white-tailed deer jumped into the pen next door that housed the Pere Davis’s deer and, on two occasions, deer jumped out of their pen and into a perimeter area in which they were still contained.
On Monday, March 18th, we tested eight blackbuck and, on Thursday of that week, we tested six Pere David’s deer and one mule deer. After nearly three weeks, we had caught, tested, and read the results on nearly seventy animals, which equals 140 captures with remarkably few casualties. All animals to this point tested negative.
On Tuesday, April 30th, our luck changed. We tested a male and three female European bison and when the tests were read on Friday, the male’s test was “suspect” and one of the females was positive. They were re-tested the following week with a more sensitive test in the eyelid instead of under the tail, and the male and two of the females were positive. We had not seen any signs of tuberculosis since the initial diagnoses in the female blackbuck, but now we were in for a long period of quarantine, treatments and endless testing. Unfortunately, I was transferred to a different area and have no record of what happened afterwards.
1974 was an eventful year for me. My two little boys, Mike and Jason were just 2 ½ years and 10 months old respectively. We had moved from the balmy, gulf coast of Florida to spend our first winter in Canada and I was in the midst of opening one of the largest zoo operations in the world. For a zookeeper, much of the work can be mundane – cleaning cages and feeding animals – but there was nothing mundane about those early days at the Toronto Zoo. We received new animals on a weekly basis – many of which I had never even heard of. We were catching, crating, uncrating, and moving animals around on a daily basis and, at one point, I found myself on a Polish freighter in the middle of the North Atlantic with a load of animals bound for Canada. So from now until the 40th anniversary of the opening of the zoo in August, I would like to remember some of those times.