Parasites of Animals

Parasites that live on and inside animals come in countless sizes and shapes - from microorganisms that are only visible in a microscope at high magnification to worms whose length is measured in feet. This page presents a few interesting examples of parasites that are found in exotic / domestic animals, but note that some of these can even make their homes in (or on) us humans.

If you'd like to skip the technicalities and get to the pictures right away, just click here.

The parasite pictures shown on this page were all taken through a visual microscope with a digital camera. You can click on any of the pictures to see a full-resolution version of the same image (but note that these might take a long time to load, depending on the speed of your Internet connection).


[click here for larger image]


The imaging system (pictured above) consists of a Nikon Eclipse 400 compound optical microscope and a set of cameras (both digital and film-based).  For those with interest in microscopy, more details about the equipment used can be found in the equipment details section below.

Classification of Parasites

Living organisms are classified using the Linnaean hierarchical scheme - in order of decreasing generality, the groupings are Kingdom, Phylum, Class, Order, Family, Genus and finally species. The classification of Protozoa (one-celled organisms) is not as well established, and we list their main phyla here. Similarly, there is some debate as to how insects should be classified, here we use the subphylum level to classify them.

There are many web resources available for further study, here are a few links to a few of the countless web sites with information about classification of organisms in general, and parasites in particular:

The main groups of parasites are as follows:

  • Kingdom: Animalia (animals)

  • Kingdom: Protista (single-celled organisms)

  • The Parasite Pictures

    Ancylostoma - the canine hookworm

    Ctenocephalides - the cat flea

    Dermacentor - the American dog tick

    Rhipicephalus - the brown dog tick

    Pulex irritans - the flea

    Trichodectes canis - the biting louse of dogs

    Paragonimus - the lung fluke of dogs and cats

    Echinococcus Granolos - the hydatid cyst tapeworm of dogs

    Dirofilaria Immitis - the canine heartworm

    Dipylidium Caninum - the cucumber seed tapeworm


    Equipment details


    The Nikon Eclipse 400 microscope is equipped with a 30W quartz halogen bulb, a brightfield / darkfield / phase contrast turret condenser (0.9 NA), a trinocular "F" eyepiece tube (two widefield 10x / 22mm F.O.V. eyepieces for visual observation plus a photo tube), and the following set of objectives:

    As the picture of the microscope used in the introduction (above) is a bit cluttered, here is an annotated version of the same picture, showing the main components of the microscope more clearly:

    All of the parasite images shown on this page were captured with a Nikon CoolPix 950 digital camera (through a 10X eyepiece) operating at an "XGA" resolution (1024x768 pixels). Pictures taken with a film-based Nikon 8008s camera (via a 2.5x projection lens) are in the works, and we hope to have them added to this page soon.

    If you have any comments or questions, please send e-mail to