Notes from the Lab

By Heather Bryan
Biologist Rainforest Wolf Project
Parasitology lab

University of Saskatchewan, Saskatoon
March 2008

Peering down the eyepiece of my microscope, I scan a slide for larval stages of parasites. I find one that is familiar-a brown, translucent egg of the tapeworm Diphyllobothrium-and begin to count. One, two ….

With the Wolf Project crew out of the field, our dedicated lab team – Maelle, Ronan, Brent, Amanda and myself – has spent countless hours scanning slides and counting parasite stages. Together, we have examined and analyzed nearly 1000 faecal samples collected from wolves and dogs during last year’s field seasons. To date, we have counted over 136,000 parasite eggs, larvae and oocysts. So far, we have detected a great number of parasite genera (taxonomic groups containing one or more species): at least 17 in wolves and 7 in dogs.

Parasites are ubiquitous and important parts of ecosystems that provide natural checks and balances . However, the delicate balance between parasites and their hosts may be disrupted by the introduction of newparasites, landscape alterations, or other stresses on host populations. The information we are collecting now will provide baseline information on parasites that will allow us to monitor and predict changes in parasite-host dynamics in response to a changing environment.

As my counter passes the 700 mark, my mind wanders along the journey that each microscopic Diphyllobothrium egg must endure to complete its lifecycle. First, a wolf or other carnivore infected with an adult worm must deposit faeces containing viable eggs into water. Eggs in the faeces then hatch into free-swimming larvae that must be ingested by zooplankton hosts. In turn, an infected zooplankton must be consumed by an appropriate fish host. Finally, the parasitized fish has to be eaten by a carnivore such as a wolf in which the tapeworm can complete its lifecycle and produce eggs.

Such an intricate lifecycle inspires a unique appreciation for the microscopic organisms I am counting. My own intestines fostered a reverence for these organisms on yet another level as I contracted a case of Giardia by unknowingly drinking contaminated tap water in the field last fall. Such a personal experience will quickly cultivate a respect for the ability of tiny parasitic organisms to affect beings much larger than themselves, and indeed the whole ecosystem.

As our lab work winds down and spring approaches, the wolf team is gearing up for another field season. In the coming year, we look forward to further discoveries about wolves and their parasites. However, we will be taking additional precautionary measures to ensure that none of our observations become too personal!

Click here to learn more about the Rainforest Wolf Project

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