Parasites Aid in Blood Testing of Zoo Animals
Here is a story that appeared in the June 27, 2008 issue of The Week.
Help from a bloodsucker
Many zoo animals do not like needles and panic when veterinarians try to take their blood. So zoo officials in Europe are letting a bloodsucking bug get the samples they need. Europe is now experiencing an epidemic of bluetongue, and farmers and zookeepers are rushing to vaccinate their animals. But vaccinations aren't always effective, so vets have to get regular samples of the animals' blood to check for antibodies. Many animals respond so badly to the threat of a needle stick that they must be sedated before a doctor enters their pen, but sedation can be dangerous. Instead zookepers are introducing the Mexican kissing bug into the cages of the needle-phobic. The bug is known for sucking blood from around the mouth of its sleeping victim (hence the name "kissing" bug). After it sucks a few milliliters of an animal's blood, vets capture the bug. Zoo vet Tim Bouts tells New Scientist that the technique works well, as long as the bugs are careful. "Once a hippo stepped on a full bug so we had to start over."
A couple of aspects of the article stood out to me. First, I find it interesting that hoofstock diseases tend to have such crude names (such as bluetongue, foot-and-mouth disease, and mad cow disease).
The technique is very innovative. Disease-free parasites may be a very good way to collect blood samples from a number of species in the future. However, the samples may not be fit for all types of blood testing. For instance, one could not use theses samples to test blood sugar levels or blood oxygenation levels. As well, if my memory serves me correctly kissing bugs are vectors for a syndrome called Chagas disease. I will assume that the kissing bugs used in the project are free of the syndrome.
Finally, I take issue with one point made in the article. The article states that many animals are afraid of needles. In my experience, that is not true. Most animals aren't scared of needles at all. However, they often are abjectly terrified of the hairless, two-legged apex predators that enter the cages holding the needles. Needles don't frighten most zoo animals. People do.