Parasites | opossumcare

Parasites:

Always make the assumption that your possums have parasites even if they test negative for them!

Parasites do not just live in the intestines, they can also effect many other organs in their bodies. If you have a negative fecal result, please do not assume that possum is parasite free! His or her life may depend on it!

Not all anti-parasitic drugs work on possums. In addition to this, they are not all dosed in the same way in which you might dose a cat, dog or other animal. Please consult a Vet or Wildlife rehabber knowledgeable in this species. DO NOT take it upon yourself to administer any medication to a possum without knowing what you are doing.

Felix

Ticks: First; wear gloves, many of the pathogens a tick carries that can infect your animal can also infect you! These are especially difficult to remove. Ticks bury their heads under the skin, and they secrete a cement like substance that firmly locks them into the host. With patience and care, you can remove the tick yourself, or you can opt to have your Vet do it. To remove it yourself, use thin-tipped long tweezers to grasp the tick as close to the animals skin as possible. Very slowly and gently, with continuous pressure, pull the tick out from under the skin. This is a delicate operation-if you pull too fast or are jerky, you may leave the ticks head (or part of it) under your pets skin. Once removed, drop the tick in rubbing alcohol to kill it. Carefully swab the animal’s skin around the bite with alcohol to kill any bacteria that may be left behind. Make a record of when this tick was discovered and removed. If you leave some behind: try to tease the rest out or have a Vet do it...you should not allow any part of it to stay in the animal.

Another Method (submitted by; Brenda Ice): Apply a glob of liquid soap to a cotton ball and swab the tick for 15-20 minutes. The tick will come out on its own and be stuck to the cotton ball.

Tape Worm: These are acquired by swallowing a flea infected with a tapeworm larvae. An opossum may swallow a flea while self-grooming. Once the flea is ingested, the larval tapeworm is free to develop into an adult tapeworm. The adult tapeworm is made up of many small segments, called proglottids, each about the size of a grain of rice. Adult tapeworms may measure 4-28 inches in length. As the tapeworm matures inside the intestines, these segments break off and pass into the stool. You will often see visible evidence of tapeworm infestation around the anus, or in the stools, appearing as small rice-like objects.

Hookworms: An opossum becomes infected by direct contact with contaminated soil, though walking in it or ingesting it. Hookworms have a complex life cycle that begins and ends in the small intestine. Hookworm eggs require warm, moist, shaded soil to hatch into larvae. These barely visible larvae penetrate the skin (often through the feet), are carried to the lungs, go through the respiratory tracts to the mouth, are swallowed, and eventually reach the small intestine. This journey takes about a week. In the small intestine, the larvae develop into half inch long worms, attach themselves to the intestinal wall, and feed on the animal’s blood. The adult worm produces thousands of eggs. These eggs are passed in the feces. If the eggs contaminate the soil and conditions are right, they will hatch, molt and develop into infective larvae again after 5-10 days.

Fleas: These make an animal miserable, can cause infection at the bites sites, anemia, and tapeworms! I have had great success using Advantage (formulated for kittens) as well as Revolution for fleas on opossums. DO NOT use on tiny babies. Bathing your possum with Dawn dish soap will kill both the fleas and the eggs.

Roundworms: visible in feces, often seen in clusters, resembling spaghetti. Roundworms or nematodes, are a group of invertebrates (animals having no backbones) with long, round bodies. They range in size from those plainly visible to the naked eye to those several hundredths-of-an-inch long and only visible under a microscope. Most roundworm eggs or larvae are found in the soil and can be picked up by the paws, ingested, or enter through the skin.

This is a picture of the stomach and some of the contents of the intestinal track of a deceased possum. Note the heavy

parasitic infestation!

Intestinal worms in a opossum.

Worms attached to the internal organs of an opossum.

Worms in the stomach of an opossum.

Besnoitia:

Opossum: Intermediate host. It is believed that they may become infected with Besnoitia darlingi by ingesting infected tissues or by ingesting food or water contaminated with oocysts excreted by cats. Besnoitia darlingi infection does not cause clinical disease in cats and no treatment is needed

Cats: Definitive hosts

Many possums can carry Besnoitia darlingi without any clinical symptoms, however severe systemic clinical disease and inflammation associated with besnoitiosis can occur. Clinical signs included trembling, incoordination, circling, blindness, poor body condition, and sudden death.

Treatment: There is no 100% effective treatment for Besnoitia darlingi.

Besnoitia is an obligate intracellular protozoan parasite belonging to the phylum apicomplexan.
It is similar to Toxoplasma.
It multiplies in macrophages and endothelial and other cells, producing large, thick-walled cysts filled with bradyzoites.
The cysts grow to become invading tachyzoites.
Stinging insects such as tabanid (horse fly) and stomoxy are thought to play a role in the transmission of this disease. Stomoxys is a genus of flies in the family Muscidae. The genus is unusual among the Muscidae in that it includes species that are bloodsucking ectoparasites of mammals.

Clinical Findings and Lesions:

Affected animals may have high fever, photophobia (avoidance of direct sunlight), edema of the skin, diarrhea, and enlargement of superficial lymph nodes.
Up to 10% of affected animals die in the early stage.
Survivors develop a chronic disease in which the parasites localize in cysts underneath the skin.
Marked scleroderma in legs, dorsum, and nose.

Treatment:

Treatment is difficult and of limited success.
Wound dressing, control of secondary infections, control of insect, and providing shade and nutrition for sick animals are good supportive treatments.
Oxytetracycline (long acting; 20 mg/kg, repeated 2 days later) during the initial stages showed good results. Similar results by using antimony and sulfanilamide.

Control and Prevention:

Separating sick animals from healthy ones have shown to decrease the appearance of new cases.
Besnoitia is often associated with coccidiosis, but varies according to species of coccidia and host.

Read about this parasite: Besnoitia

Current Opossum Deworming Protocol 7.22.18

Protocol Written by Kenneth D. Jones DVM

Ivermectin and Fenbendazole are used in combination to treat gastrointestinal worms and lungworms in the Didelphis Virginiana.

Use Fenbendazole (Panacur) 100mg/ml and Ivermectin (injectable but given orally) 10mg/ml in combination.

Fenbendazole Dose: 25mg-50mg per kilogram.

You can buy fenbendazole over the counter under the brand name "Safeguard". To prepare this for a possum:

Take1 pouch Safeguard = 222 mg.

Mix the whole thing with 10 mL water.

Each ml = 22 mg.

Dose is 50 mg/kg (orally) every 24h X 14 days.

Keep the mixed solution refrigerated and shake well before using.

Dosing Ivermectin in pounds:

Low end: 0.12ml/lb once a day for 14 days (recommended for heavy worm burden)

High end: 0.23ml/lb once a day for 14 days

Ivermectin is given orally at dose of 0.1-0.2 mg per kilogram.

Dosing Ivermectin in pounds (low end of the dosage):

1.5 – 3.4 lb opossum gets 0.01ml once a day for 14 days
3.5 – 5.4 lb opossum gets 0.02ml once a day for 14 days
5.5 – 7.4 lb opossum gets 0.03ml once a day for 14 days
7.5 – 9.4 lb opossum gets 0.04ml once a day for 14 days
9.5 – 12.4 lb opossum gets 0.05ml once a day for 14 days
12.5 – 14.4 lb opossum gets 0.06ml once a day for 14 days
14.5 – 16.5 lb opossum gets 0.07ml once a day for 14 days

Add this mixture to palatable food such as applesauce or yogurt or administer via a feeding tube.

Continue once a day administration of the combination for 2 weeks. If heavy worm burden was present or if you are still seeing worms in the stool, you may have to retreat.

Side Notes: Things to consider

Every rescued opossum has internal parasites. Treating every opossum for parasites is NECESSARY!
Internal parasites are detrimental to the opossum’s health.
Nematode infestation contributes to sepsis, compromises overall health, delays recovery, and often leads to death.
Using the low range prevents killing too many worms at one time, which can lead to intestinal obstruction, esophageal blockage or suffocation.
Adult stomach worms may be seen in the stool for up to two weeks.
Consider applying a dose “Profender” or “Revolution” on the opossum before releasing the opossum back into the wild.

Fleas:

We get lots of folks writing in about fleas. There is no pat answer on what to do about fleas on an opossum without knowing the details about the animal:

Is this a brand-new baby you just found?
Is the animal injured, sick or compromised in any way?
Is this a pet possum or a wild possum?

The solutions to a problem with fleas would depend on the answers to those questions.

How to treat for fleas:

Capstar: This product was made for puppies and kittens weighing 2 lbs and up, however other rehabbers have given 1/4-1/2 tab for babies less than 1 lb. It will kill fleas very quickly, (usually 90% within 4-6 hours) and it is given orally. It only works for about 24 hours however. Generally, fleas only stay on the animal while they are actively feeding. You want to use the 11.4 mg size tablets. You can also crush 1/2 tablet in 2 ml water and apply externally anywhere maggots/eggs are visible, especially ears, nose, eyes, or anus. See dosing chart below.

Capstar is simply Nitenpyram, and you can buy the generic form for much less money:

Guardian website: https://www.theguardianpets.com/store/p77/niten11mg.html

Revolution: Kills and protects against fleas, heartworms, roundworms, hookworms, and ear mites for appx 30 days. Use 1 drop between the shoulder blades. I like this because it is so effective against a broader number of parasites, however it is prescription so a little harder to obtain. Great for treating possums right before you release them.

Advantage: (Regular Advantage) I have used this successfully on possums. Kills and protects against fleas, roundworms, hookworms and whipworms. Use 1 drop between the shoulder blades. Great for treating possums right before you release them.

Bathing the animal in Blue Dawn Ultra: This is often used on wildlife that get caught in oil spills, the degreasers it contains, breaks down the exoskeleton of fleas and kills them quite quickly. You need to soap them up well, and leave it sit for a few minutes before rinsing them off. Be mindful not to get it in their eyes. Keep a flea comb or tweezers handy to grab the fleas that will ultimately be crawling around on the face and ears.

***Bathing a wild possum can be VERY stressful on them so I rarely take this route.

Flea Combs: I personally don’t have a ton of luck with these, but if the animal only has a very small number, it can’t hurt to try. These can be useful when used in conjunction with other methods.

Ringworm:

Despite its name, ringworm, is NOT caused by a worm, but by a fungal skin infection that can affect humans and many animal species. The technical term for ringworm is "dermatophytosis". The disease gets it name from the appearance of a “ring” type rash that develops on the skin of the infected person or animal. it appx two to four weeks before the animal shows any clinical signs. You might observe areas where the hair is gone and crusts or scales may develop on the skin in the affected areas. The skin may look red and itchy. The appearance of a circle or ring in the animal’s fur may be seen.

It's important to wear gloves and protective clothing when handling the animal, or cleaning the animals bedding and habitat. Wash your hands frequently and disinfect the animals area, bedding, and any other items the animal has been in contact with, using a 10% (1:10) bleach and water solution. Keep the animal isolated away from other animals.

How do you catch ringworm?

Ringworm produces spores and these spores live in the environment. Both animals and humans alike contract ringworm by coming into direct contact with these spores. You do not necessarily have to come into contact with an infected animal or person to catch ringworm, the spores can even be present in soil.

Treatment: Topical and Oral

There are two main types of topical treatments: Lime Sulfur dips and antifungal shampoos. Lime Sulphur dips have a very strong odor but seem to be more effective than anti-fungal shampoos.

Antifungal shampoos are often paired with a disinfectant like chlorhexidine, as they work well together to combat ringworm. These typically need to be used twice weekly.

There are also anti-fungal ointments that can be applied to the effected areas, but these are not overly effective used by themselves.

Oral medications work by making the fungus unable to reproduce and spread. In most cases it is recommended to use oral and topical measures together. Some oral anti-fungals can have gastrointestinal side effects.

Parasites:

Besnoitia:

Besnoitia is an obligate intracellular protozoan parasite belonging to the phylum apicomplexan.

Treatment:

Control and Prevention: