Internal parasites are one of the most frequently encountered medical problems in captive tortoises. Most tortoises carry some parasites and they can proliferate to large numbers when tortoises are stressed or live in crowded enclosures. When tortoises are kept in poorly sanitized environments they'll continue reinfecting themselves and each other.
Many tortoise keepers perform periodic microscopic evaluations on their tortoises' feces to detect the presence of common parasites like pinworms and roundworms. This can be handy if you keep a large number of chelonians. For one or two tortoises, it's easier just to take a fecal sample to the vet.
In addition to gross examination, two primary methods for performing fecal exams at home are the direct smear and the fecal floatation. For more accurate results, it's best to use a combination of both techniques. Scroll down for exam info.
DIY fecal exams are great for early detection and routine screening for common tortoise parasites. Frequent home screenings increase the change of detecting parasites that may only be seen intermittently in the feces. If three or more subsequent DIY fecal floats and smears are negative over a period of several weeks, your tortoise is probably free of common parasites or has a low parasite load.
DIY fecal exams also work well as pre-screenings. In other words, a positive finding will alert you to take your tortoise to a reptile veterinarian. If you do find something suspicious, it's always smart to verify the findings with your veterinarian.
If you are a new tortoise keeper, always consult your veterinarian for the correct medication and dosing. Some deworming medications, like Panacur (fenbendazole, FBZ) used for nematodes (worms), are available over-the-counter, but many others need a prescription.
If you can't figure out what parasites you found in your tortoise's poop, take photos and show them to your veterinarian. It's also a good idea to take a fresh fecal sample with you for a thorough, professional lab analysis.
WARNING! Never use a dewormer with the active ingredient ivermectin (for example, Heartgard for dogs and cats) on tortoises or turtles. Ivermectin is toxic and deadly for chelonians.
Not everything you see moving under the microscope is pathogenic (disease causing). Tortoises have many beneficial bacteria present in their bowels to help break down food. This bacterial action is further helped by "good parasites". Routine deworming may disrupt this essential process.
For example, Nyctotherus, a ciliated protozoan, is considered an important part of the intestinal microflora. The 2008 book "Zoo and Wild Animal Medicine Current Therapy" by Fowler, DVM, DIPL ACZM, ACVIM, ABVT & Miller, DVM, DIPL ACZM lists both Nyctotherus and Balantidium ciliates as beneficial organisms in giant tortoises and thus should not be treated. Mader's book Reptile Medicine and Surgery (2006) agrees with the nonpathogenicity. Though, Klingenberg in Understanding Reptile Parasites (2007) writes that Balantidium coli is the only ciliate known to cause disease in tortoises.
As with most areas of tortoise care, there's not always a consensus of opinion among tortoise experts and keepers about parasite treatment. Many keepers feel that tortoises should not be dewormed unless a fecal exam shows a heavy enough parasite load and/or the tortoise exhibits symptoms. Others think that routine deworming is a necessity for captive tortoises to help keep the parasite burdens low.
Using a microscope is fun, but it takes some practice to recognize what you are looking at. You may see so many different bits, pieces, sprinters, dashers, stretchers, and swirlers in the fecal sample under the microscope. Sometimes it's just a big party there. :O) The books listed below will help you to identify the most common reptile parasites.
A recently imported Greek tortoise passed a bunch of roundworms with feces while soaking in warm water. These parasitic worms were 3-5" long.
1.) Simple digital microscopes
There are many different kinds and brands of digital microscopes on the market. Over ten years ago, when I first wrote this article, I often used my simple and inexpensive Celestron 44330 biological microscope for quick fecal exams. It can be used by itself with the eyepiece as an optical microscope, or it can be hooked up to a computer to view the images digitally on the screen.
This little Celestron microscope is just powerful enough to see parasitic worm eggs in a fecal sample. The eyepiece is 20x and the objective lenses allow 5x (100 power), 10x (200 power), and 20x (400 power) magnification. It can be used as a basic screening tool for detecting common parasites of reptiles and other animals, like dogs, cats, goats, birds, etc., at 100x to 400x magnification.
This mini Celestron microscope can be taken anywhere because is battery powered, small, and light weight. This model may not be available anymore, but there are many other brands and styles.
2.) Trinocular microscopes
A higher precision microscope with a 1000x magnification capability and special stains (coloring with dyes) may be required to identify some of the smallest protozoan parasites. For the sharpest image, a total magnification of 1000x and above requires the use of immersion oil on slides and an objective lens specifically designed for it.
My other microscope is a 40x-1600x digital trinocular microscope with a USB camera (imager). This microscope allows simultaneous focusing, in other words, it allows me to view images on the computer screen and through the eyepieces at the same time. This microscope is a lot bigger, heavier, and more expensive than the small Celestron above. It's definitely not portable. :O)
3.) Microscope imagers
If you already own an optical microscope, you can buy a digital imager for it. Digital imagers allow you to view microscope slides on your computer screen and photograph/record your findings.
Digital imagers are not stand-alone cameras. They need to be connected to a regular microscope to view and capture images and video.
Left: Small, light-weight, battery-powered microscopes, like this entry-level Celestron (100x-400x), are portable and very easy to use, even for a beginner or a small kid. Great for family hikes in the nature, too.
Right: My more powerful digital trinocular microscope (40x-1600x) with a USB camera (imager). It's big and heavy. Definitely not portable.
1.) Fecal gross exam
First, perform a gross examination on the poop. In other words, inspect the poop visually for color, texture, and consistency.
Is the poop dark and solid, in other words, normal? Any diarrhea? Diarrhea can be caused by parasites or a wrong kind of diet. Does it contain mucus or blood? Both can be signs of parasites.
If you see adult worms in the poop, it's obvious the tortoise has intestinal parasites. However, not seeing any worms does not necessarily mean the tortoise is parasite free. Usually, intestinal parasites are diagnosed by finding worm eggs, larvae, or protozoan parasites under the microscope. They are invisible to the naked eye.
2.) Fecal smear exam
A direct fecal smear can be used to detect mobile protozoan parasites (e.g. Giardia) in the trophozoite stage (motile feeding stage). Use a poop sample that's less than one hour old. In an older poop sample, trophozoites will degenerate and became non-identifiable.
Just put a very small bit of fresh poop onto a slide and add a drop of distilled water or saline. Saline solution for rinsing contact lenses is ok to use. Stir gently with a toothpick. Put on the cover slip and observe under the microscope.
Fecal smear is a simple test to perform, but it may give a false negative, especially with low parasite levels, because only a tiny piece of poop is used for the exam.
Always use disposable gloves when dealing with feces and parasites. Disinfect all used surfaces afterwards.
3.) Fecal float exam
Performing a fecal float involves more steps than the direct smear. In addition to the microscope, glass slides, and cover slips, you'll need a floatation fluid and test tubes.
The fecal float test is used to detect parasite eggs, larvae, oocysts, and cysts in poop. The higher specific gravity of the floatation fluid causes them to concentrate on the surface (and attach to the cover slip) due to their lighter density. Consequently, parasites are easier to track down under the microscope because there are more of them in the sample.
Steps and needed supplies for the fecal float exam are described below.
Computer screen with live video of fecal float slides using the simple, portable Celestron microscope and attached camera. Parasite eggs shown at 200x and 400x magnification.
Here's how you can perform a fecal float analysis on tortoise feces at home using the Fecalyzer test cup. (You can also use a vial or any small, clean tube if you don't have a Fecalyzer cup at hand.)
1.) Put on disposable gloves.
2.) Remove the green insert from the Fecalyzer test cup.
3.) Pick a small piece of fresh poop, about the size of a pea or more, with the tip of the green insert.
4.) Put the green insert with the poop back into the test cup and snap it down to secure it.
5.) Add fecal floatation solution, like Fecasol or Fecamed, into the cup up to the arrow, about half-way up.
6.) Stir and agitate the poop well in the fluid using the green insert. In other words, turn the green insert back and forth rapidly to break the poop apart. (Or, smash and stir the poop well with a toothpick in a small vial if you don't have a fecal float kit.)
7.) Fill the test cup with Fecasol liquid all the way to the top. The solution should arch over the top forming a curved upper surface called meniscus. Do not overflow.
8.) Put a microscope cover slip over the cup. It must touch the Fecasol solution (pic below).
9.) Wait about 20 minutes to allow the microscopic nematode eggs to float to the top and collect onto the cover slip. Recommendations for the wait time vary from 10 minutes to 30 minutes.
10.) Carefully lift off the cover slip straight up and put it wet side down on a microscope slide.
11.) Put the prepared slide under the microscope and examine immediately. To start, try using 100x or 200x magnification for scanning and 400x for closer identification.
12.) If you are viewing the slides on the computer screen, photograph and/or record your findings for later review.
13.) When done, disinfect all surfaces and throw away used cups, slides, gloves, and other contaminated items.
Left: A prepared Fecalyzer test cup. A microscope cover slip is placed on top of the arched (meniscus) test solution. Waiting for the nematode eggs to float to the top and collect onto the microscope cover slip.
Right: A gallon bottle of Fecamed (generic Fecasol) solution and smaller dispensing bottles.
a.) Floatation medium
Fecasol (sodium nitrate) by Vetoquinol and its generic version Fecamed are commonly used solutions for floatation technique fecal analyses. They are typically sold in one gallon bottles for $15-$30 depending on the brand and seller.
I fill small, plastic dispensing bottles with floatation fluid and saline. These bottles are available in many sizes. The ones in the photo on the right are 8 oz. Dispensing bottles are great because they allow me to both squirt the solutions to float test kits and add them drop by drop. For example, to add a drop of saline to a slide or to add drops of floatation medium to a test vial to form the meniscus.
b.) Vials & kits
You can use a small vial for the poop sample, but using a fecal floatation system kit (Fecalyzer by Vetoquinol or a generic), makes the test process easier. Float kits are used for poop collection and testing. They include cylinders (cup), caps (lid), and strainers (green insert). You can buy these test tubes individually for less than $1 each or in a box of 50 for $25-$30.
c.) Slides & cover slips
Microscope glass slides and cover slips are inexpensive. A box of slides with cover slips costs around $10-$15.
Supplies for a fecal float test for parasites: microscope, slides, cover slips, test tubes, and floatation medium. This one is a digital trinocular microscope with an attached USB camera on top (partially off picture).
Bringing new tortoises into your existing group is always a health risk and a strict quarantine is a must. Imported tortoises usually have the worst loads of parasites and typically need deworming for both parasitic worms and protozoa.
For over ten years all my tortoise groups have been "closed colonies" with no new tortoises coming in. In the past, when I still purchased additional animals, I mostly used microscope fecal exams on newly acquired tortoises to scan their feces for parasites. I also quarantined all new animals for at least a year.
I wrote this page over ten years ago. Nowadays, I don't really do fecal exams anymore. I do not routinely deworm my tortoises either. If one of my tortoises was sick, or had visible worms in his poop, I'd just take him to the vet for check up.