How to Treat a Snake for Internal Parasites

How to Treat a Snake for Internal Parasites

Internal parasites are common in wild reptiles. However, improper husbandry, overcrowding, and stress can also lead to a severe infestation in captive snakes. Some of the most common internal parasites in snakes include, protozoans, nematodes, trematodes, and pentastomes.

Treatment depends on the type of internal parasite, but often includes a dewormer. For protozoal infestations, such as amoeba and flagellates, antiprotozoals or antibiotics may be needed to get your snake parasite-free and healthy again.

Any snake that shows signs of internal parasites, such as weight loss, loss of appetite and weakness, should be checked by a herp vet. If left untreated, parasitic infestations can contribute lead to death. Your vet will need a fecal sample to test for the presence of internal parasites.

How Common Are Internal Parasites in Snakes?

Parasitic infections increase a snake’s risk of health complications, and even death, if left untreated for too long.

Internal parasites are more common than most snake owners believe. While many wild-caught snakes are known to harbor internal parasites, even captive-bred snakes can become infested.

Parasitic infestations in captive snakes originate from poor husbandry techniques, lack of sanitation, overcrowded conditions, and stress.

  • According to Zoo Biology, 88% of the snakes studied were found to be infested by internal parasites, such as strongyle, Strongyloides/Rhabdias spp., spirurid, ascarid, pseudophyllidean tapeworm, pentastomid, Capillaria spp. and acanthocephalan.
  • Another study by Acta Veterinaria Scandinavica, found twelve different groups of endoparasites in 47% of examined snakes.

Check for the common symptoms of internal parasites, such as anorexia, regurgitation or vomiting, changes in feces, and diarrhea. This can help reduce the risk of complications and death in snakes.

snake parasite treatment

Types of Internal Parasites in Reptiles

Snakes can host many parasites, some of which can cause multiple issues. Here are the different kinds of snake parasites:

Entamoeba Invadens

Entamoeba invadens are the most serious protozoal pathogens in snakes that cause signs and symptoms such as, anorexia, vomiting, weight loss, diarrhea, and death. It’s the most common causative agent of serious amebiasis in snakes.

Certain snakes, such as garters and northern black racers may serve as carriers without being affected by the E invadens. Other resistant snakes include cobras and kingsnakes. Resistance to this strain may be an adaptation that allows these snakes to eat other snakes. Snakes, such as boas, colubrids, vipers, elapids, and crotalids are vulnerable to E invadens.

E invadens is typically treated with the antiprotozoal, metronidazole. Paromomycin and tetracycline may also be used but they’re ineffective against hepatic infestations. In addition to metronidazole, owners must follow strict sanitation measures for the treatment to be effective.

Your vet may also prescribe other antimicrobials to treat secondary fungal and bacterial infections.


Flagellates are another type of protozoal pathogen that can be treated with metronidazole. Flagellates, such as Hexamita spp., inhabit the intestinal tract and cause intestinal disease in snakes.

Kingsnakes, indigo snakes, and uracoan rattlers require a lower dosage of metronidazole for flagellate infestations. Some studies also indicate that drugs, such as benzimidazoles, may be used to treat flagellates in snakes.

Coccidial Organisms

Treatment for coccidia includes sulfadimethoxine, which must be persistently used until the infection is cleared. This often takes 2-4 weeks. Your herp vet will determine the progression with routine fecal samples.

Another useful drug for treating coccidia in snakes is trimethoprim-sulfa. However, sulfa should be used cautiously in snakes that suffer from renal problems or dehydration. If needed, your vet will recommend a balanced electrolyte solution to eliminate possible side effects.

There are many different types of coccidial organisms that may affect snakes. Some of them include:

  • Isospora found in the gallbladder and intestine
  • Klossiella affecting the kidney
  • Eimeria in the gallbladder

The severity and treatment of the disease depend on the type of coccidia as well as the snake that is affected. Coccidia has direct life cycles, which means they can proliferate in large numbers, especially in immunosuppressed snakes.

In addition to the above drugs, it is critical that owners follow a strict cleaning routine to ensure the complete eradication of coccidia in their snakes. This includes daily removal or feces. Food and water contaminated with feces should also be replaced regularly.

Certain insects may act as another source of contamination. They retrieve the oocysts while collecting fluid from snake feces. Therefore, snakes and other food sources must be removed every day to avoid contamination during treatment.


Cryptosporidium is another protozoan that causes Cryptosporidiosis in snakes. The disease is often associated with postprandial regurgitation, weight loss, diarrhea, and chronic debilitation.

According to Applied and Environmental Biology, contaminated water, and feeding wild-caught prey are common causes of Cryptosporidiosis.

Cryptosporidium affects the intestinal mucosa, leading to significant thickening of the gastric folds and loss of segmented contractions of the intestines. Oftentimes, a mass in the gastric area may be palpable in snakes. Endoscopic examination and contrast radiographs will show the thickening of the gastric folds.

Your vet will diagnose the presence of this parasite using acid-fast stains on your snake’s feces or regurgitated materials as well as endoscopic gastric biopsies.

A large number of treatment measures have been recommended for cryptosporidiosis in the past. However, only hyperimmune bovine colostrum has been reported to be effective in treating the infection. In most cases, intensive care will stabilize the snake’s condition and prolong its life.

The disease was previously thought to zoonotic, but scientists have now found that the species of cryptosporidium found in reptiles do not affect mammals.

Pentasomic Infection

While pentastomes (also called tongue worms) can inhabit any tissue inside a snake’s body, they’re sometimes linked to pneumonic signs, such as difficulty breathing and nasal discharge. Symptoms of pentasomic infections often depend on the migration path of the parasite and tissue responses.

There aren’t any treatment options available for pentasomic infections that are fully effective. Ivermectin at 5 to 10 times the normal dosage, and praziquantel is given at a dosage of 8mg/kg have been reported to bring down shed ova numbers. However, these drugs may not completely eliminate the worms.

Newer treatment methods involve endoscopically finding and removing adult parasites.

Pentasomic infections are known to be common among snakes kept in unsanitary conditions. According to the CDC, early recognition of pentasomic infestations is critical as it can be passed on to humans, dogs, and other pets.


Trematodes are a type of helminth. Helminths are worm-like parasites that inhabit snakes kept in overcrowded and unhygienic conditions. Poor husbandry along with the stress of captivity in an enclosed environment increases a snake’s risk of parasitic infestations with direct life cycles. Treatment for helminths involves eliminating intermediate hosts from the environment and the suffering snake.

Trematodes include two groups of parasitic flatworms, called flukes. Flukes are internal parasites with complex life cycles involving at least two hosts. Pathogenic trematodes often infect the respiratory system, oral cavity, ureters and renal tubules of snakes.

If your snake is suffering from a trematode infestation, your vet may prescribe praziquantel. In some cases, chemotherapeutic agents may also be used but they aren’t often successful.


Snakes act as intermediate hosts for a large number of tapeworm species. While most tapeworm infestations are nonpathogenic in wild snakes, anorexia and death have been reported in the past. Tapeworms have a complex life cycle with a limited geographic range of intermediate hosts. This limits the likelihood of captive snakes being infected with tapeworms.

Tapeworms can be seen as rice-like segments in an infected snake’s feces. The larval stages of tapeworms may also be found in the connective tissue layer beneath the skin. These can be surgically removed by a vet.

If your snake is infected by tapeworms, your vet will prescribe a tapeworm medication called praziquantel. The medication should be repeated in 2 weeks.

Any swelling under the skin caused by a tapeworm infection will have to be removed surgically as well.


Like other parasites, nematodes may cause weight loss, anorexia, and debilitation. Nematodes have a direct cycle and can be transmitted by the ingestion of eggs or larvae. The larvae have also been seen in swellings throughout the body wall, indicating that they may be able to penetrate the skin as well.

Parasitism is extremely common in contaminated environments. Because nematodes can exist in free-living form, proper husbandry techniques, daily cleanings, and regular full cage sanitation are essential in keeping these parasites away.

Fenbendazole is often the medication of choice for eliminating nematodes. The good thing about fenbendazole is that it may also have an antiprotozoal effect, in case your snake is suffering from a protozoal infestation. Fenbendazole can be administered orally.

Another oral medication used in treating nematodes is piperazine. Keep in mind that most medications used for parasitic infections should be repeated at the required intervals, as recommended by your vet. Persistent drug therapy will ensure the successful removal of any larvae that may have progressed to adult stages inside the snake’s intestines.

Your vet may recommend rotating medications in case the worms become resistant to certain drugs.

Spirurid Worms

Spirurid worms infect the blood vessels, coelomic cavity, and mesentery (a fold that attached the stomach, pancreas, small intestine, spleen, and other organs to the abdominal wall).

These parasitic worms need a mechanical vector (e.g. mosquitos and ticks), therefore, captive-bred snakes or snakes in long-term captivity are less likely to be infested by spirurid worms.

Because spirurid worms require mechanical vectors to complete their life cycle, keeping the cage and all its items clean is the best way to keep these parasites at bay.

Treatment for spirurid worm infections involves raising the tank temperature to 95-98 degrees Fahrenheit (35-37 degrees Celcius) for 24-48 hours. However, higher temperatures may not be tolerated by snakes that are adapted to cool environments. 

Talk to your vet about any additional measures that can be taken to control a spirurid worm infestation. Your vet may prescribe fenbendazole or piperazine, depending on your snake’s condition.


Ascarids are a type of parasitic nematode worm that is also known as small intestinal roundworms. They are known for frequently infecting reptiles and for causing severe lesions and death in infected snakes.

Signs and symptoms of ascarid infection include frequent regurgitation of partially digested food and anorexia. This parasite may also lead to significant lesions in the digestive tract. Overtime, ascarids may lead to abscesses and penetrate the intestinal wall, debilitating the affected snake.

In addition to prescription medication given by your vet, you’ll also have to frequently clean your snake’s cage and avoid feeding it wild-caught prey to prevent re-infection.

Snake Internal Parasite Treatment Methods

Fenbendazole50 mg/kg per day for 3 days, repeat in 2 weeksNematode infestation
Ivermectin0.2mg/kg, repeat in 2 weeksNematode infestation Pentasomic infection
Iodoquinol50 mg/kg per day for 21 daysAmoebiasis
Metronidazole25-50mg/kg per day for 1-2 weeksAmoebiasis Flagellate infestation 
Paromomycin100mg/kg daily for 14 days, then 2 times per week for 3 monthsCryptosporidiosis Amebiasis
Praziquantel10mg/kg, repeat in 2 weeksTrematode infestation Pentasomic infection
Toltrazuril5-15mg/kg, 3 treatmentsCoccidiosis
Trimethoprim sulfadiazine30mg/kg once, then 15mg/kg for 21-28 daysCoccidiosis
Sulfadimethoxine90mg/kg every 24 hours, then 40mg/kg daily for 1 weekCoccidiosis

Treating internal parasites in snakes is simple, but should be taken seriously. If left untreated, parasitic infections can lead to death.

If you notice any telltale symptoms of a parasitic infection, such as weight loss, regurgitation, loss of appetite and unusual feces, bring a fresh fecal sample to your vet.

If parasites are present in your snake’s feces, your vet will prescribe a dewormer, along with another antimicrobial agent to eliminate secondary bacterial and fungal infections.

As always, it’s always best to follow proper husbandry techniques and avoid wild-caught prey when feeding your pet snake. Freezing items before feeding also kills most parasites.

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