Using the Tutorial



About this site

In 1997, parasitologists at the Universities of Alberta and Calgary decided to offer a joint undergraduate course on the Principles of Parasitism, with lectures given by live videoconference. It was decided to forego the traditional "sit-down-at-a-microscope" laboratory in favor of a lab that was completely web-based. This web site evolved as part of that project. Over the years we have had numerous requests from around the world for access to the web lab. As the site has evolved, it has become necessary to password-protect parts of the site that deal with our teaching function. We have decided to extract the basic laboratory component of the site and make it freely-accessible. The result is this site you are now viewing.

The full web site that we use in teaching our courses (ZOOL 352 at the University of Alberta and ZOOL 483 at the University of Calgary) is password protected and available ONLY to registered students in those two courses. These are NOT "distance learning" courses that can be taken for credit by students outside of our two universities because the lecture portion of the course requires attendance at the live lectures.

This site is intended as an introduction to the diversity of organisms that have adopted a parasitic existence. Many parasites have free-living relatives, while others are exclusively parasitic and often take on bizarre forms.

This site is not trying to sell you anything. Its purpose is to educate the public about these weird and wonderful creatures.

Navigating this web site

These are the navigation buttons you will use most frequently while studying material in the tutorial.

Most of this tutorial will present you with a screen divided into 2 or 3 frames, which are parts of the screen that contain separate content and can be scrolled through independently. On the left will be a list of study material. This index will remain visible at all times. When you click on an item in this list, text or graphics will appear in a frame to the right. If the item is a diagram or photo, it will appear in the center frame with the word Comments or Description above it. These comments or descriptions should load automatically in the right-hand frame in most browsers capable of interpreting JavaScript, but if they don't, just click on them to have the some descriptive text appear in the right-hand frame. You will be able to scroll through all the text on the right and still have the image remain in view in the center frame.

When pages are first loaded the frames are a default size. You can always resize the frames on your own display by placing the cursor at the frame margin and dragging it larger or smaller. Most graphics have been sized to make them as small as possible without causing unacceptable reduction in quality.

When your monitor is displaying frames, and you hit the "Back" button on your browser, you back up through the sequence of frame displays you have just made, in reverse order.

Overview of the Tutorial

This tutorial currently provides the following types of content:

Morphology, and Life Cycles

The laboratory tutorial teaches principles of parasitism from a taxonomically-oriented perspective. It surveys all major groups of parasitic animals. For each major taxon there will be a generalized morphological description and life cycle, and detailed descriptions of the morphology and life cycle of several representative species.

This part of the tutorial is organized into a series of seven self-guiding laboratories (Labs 1-7), accessed through the To Labbutton and following the Lab Outline link. This presents you with a list of all parasite species covered in the tutorial, arranged under a very general classification scheme, and provides a connection to a "home page" for each of the species.

The home page of each species has a consistent format.

Drawings provide a stylized representation of structure and are particularly useful to illustrate fine detail. Remember that drawings are often composites based on examination of many specimens, sometimes using a variety of methods. Few parasite specimens actually look like exactly like their drawings.

Photographs are the closest thing to the actual specimen that can be provided on your computer screen, but they have some limitations you should be aware of.


On a primitive but still useful level, classification schemes provide a convenient way to pigeon-hole organisms and information about them, particularly on a topic such as parasitism that involves diverse organisms spanning numerous phyla. A more important function of classification schemes is to reflect evolutionary affinities among organisms.

The parasitic life-style has arisen on numerous independent occasions, in a large number of taxa. Although there are many features that are common to parasitism wherever it occurs, there are others that appear only within certain taxonomic groups, and they tend to be characteristic of those groups. This provides considerable ability to extrapolate about the characteristics of new species, and the importance of this cannot be overemphasized. There are hundreds of thousands of parasitic species, of which only a fraction have been described, and life cycles have been determined experimentally for only a small fraction of the described species.

The classification scheme provided in this tutorial is a hybrid of the many schemes that exist. It is a very simplistic scheme that omits many intermediate levels of classification, and also omits taxa for which no study material is available. It has been chosen for convenience only.

Special Topics

This material approaches parasitism from a topic-oriented perspective. These topics cover various aspects of parasitism, and examples for each topic are drawn from all taxonomic groups of parasites. For the most part, the species and photos used as examples in this section, and the comments made on them, are the same ones that were used in the "Morphology, Life Cycles and Classification" laboratories. Students who have been synthesizing information while studying the "Morphology ... " laboratories should find relatively little that is new in these Special Topics. However, the different perspective (and redundancy) of Special Topics may help other students firm up their understanding of these important concepts.

This part of the tutorial is organized into two self-guiding laboratories (Labs 8-9), accessed through the Lab Outline.


A glossary is available which provides brief definitions for parasitological terms used in the tutorials as well as many more general terms. Photos accompany many of the definitions. These are small size, low resolution versions of photos you will have seen elsewhere in the tutorial, and are provided more to jog your memory than to be direct objects of study.

There is a direct link to the Photo Glossary from the Lab Home page. You can use it like an ordinary dictionary. In addition, there are numerous places, in the tutorial where terms are "hot linked" to the glossary. Just click on the term, and a definition appears. These hot links bring up an short version of the glossary that doesn't include the photos, so that it loads more quickly.

How do I ask questions?

We are unable to provide any support to resolve problems you experience trying to use this web site.

We are also unable to answer any questions you may have on the content of this site. Visit your local library, ar talk to a parasitologist at your local university or college. Most of them are quite friendly (and quite normal) people!

I think I am infected with a parasite

If you think that you, or your pet, are infected with a parasite, then you are urged to seek advice from a qualified health care professional, either medical doctor or veterinarian. This site provides some basic information on a variety of human, domestic animal, or wild animal parasites but is not intended to provided definitive diagnoses.


We will accept no responsibility for the accuracy of information in this site or the uses made of it by individuals viewing this site. There are many good textbooks on general parasitology in your local university or municipal library which may be consulted if you want more detailed information.


This web site has been constructed using simple coding to work properly on as wide a range of browsers as possible. Below are some problems you may encounter and the solution.

I can't see all of a menu, picture, or photo

I get a warning from a pop-up blocker

I can't view the animations

I can't view the movies

I can't hear the sound files

When I click on a link, nothing happens or it links to the wrong place