Common Diseases of Pet Snakes

By Gregory Rich, DVM; Laurie Hess, DVM; Rick Axelson, DVM

What are some of the common diseases of pet snakes?

The following are common conditions of pet snakes: infectious stomatitis (mouth rot), intestinal and skin parasites, skin infections, respiratory disease, septicemia, and viral diseases such as inclusion body disease.

What are the signs of these diseases?

The signs of these diseases are

Infectious stomatitis

Infectious stomatitis (“mouth rot)” is an infection of the mouth that appears as pinpoints to patches of hemorrhage on the gums, or as an excessive amount of thick mucus that often contains blood and/or cheesy accumulations of pus. There will often be a very sour odor noticeable around the snake’s hea

In severe cases, the snake has a severely swollen mouth, is open-mouth breathing, and is not eating. This problem may be secondary to a viral disease, an injury to the mouth, or issues such as poor nutrition, inadequate cage cleaning, overcrowding, or improper environmental temperature or humidity. (Photo at right shows a green anaconda; photo courtesy of Gregory Rich, DVM.)


Many types of internal parasites (various helminths, protozoal parasites, and species of coccidia) and external parasites (ticks and mites) are common in pet snakes.

Intestinal parasites often do not cause obvious signs but are detected in an annual physical examination and microscopic analysis of fresh feces. However, they may cause diarrhea, breathing difficulties, regurgitation, gas distension of the intestines, anemia, and weight loss.

Cryptosporidiosis is a protozoal parasite that can infect snakes. It causes thickening of the stomach muscles, which appears as a round, mid-body swelling, as well as impaired digestion, vomiting, and weight loss. Some snakes are infected but show no signs and shed this contagious parasite in their stool, exposing other susceptible snakes to infection. Helminths (worm-type parasites) and motile protozoa can cause poor digestion and weight loss.

External parasites such as Ophionyssus mites can carry disease-causing bacteria or viruses. Both mites and ticks suck blood from your snake and, if present in high enough numbers, can cause severe anemia.

Skin infection

Skin infection (dermatitis) is often seen in snakes and other reptiles kept in environments that are too moist and/or dirty. Snakes may have red, inflamed skin with numerous small, blister-like lesions on the underside of the snake, making them easy to miss. These fluid-filled blisters may become infected with bacteria and, if not treated promptly, may progress to severe skin damage, septicemia (a bacterial invasion of the bloodstream), and death.

Snakes kept in conditions that are too dry, without adequate humidity, may retain skin when they shed and develop bacterial infections of the skin from debris building up under the retained skin pieces. (Photo at right shows a pet ball phython; photo courtesy of Gregory Rich, DVM.)

Respiratory disease

Snakes have a unique respiratory tract. Most snakes have only one functional, simple lung. The right lung is the predominant lung. The left lung is generally reduced in size or completely absent. Boas and pythons are the exception, as they have both right and left lungs. Snakes do not have a diaphragm, so there is no muscle separating their chest cavity from their abdominal cavity. They use the muscles associated with their ribs and body wall to pump air in and out of the lungs. The lung can occupy much of the snake's body between the heart and the hind end.

"Most respiratory infections in snakes are caused by bacteria and may occur in conjunction with stomatitis."

Most respiratory infections in snakes are caused by bacteria and may occur in conjunction with stomatitis. Viruses, fungi, and parasites can also factor into respiratory disease, as these infections can decrease the snake’s immune response to bacterial invasion of the respiratory tract. Snakes with respiratory infections may have excess mucus in their mouths, nasal discharge, lethargy, loss of appetite, wheezing, and may make “gurgling” sounds or breathe with an open mouth.


Septicemia is a condition in which bacteria, and the toxins they produce, proliferate in the blood stream and other body organs. Snakes with septicemia are critically ill and are often near death. They exhibit lethargy, lack of appetite, open-mouth breathing, and often have a red discoloration to the scales of their bellies.

Viral diseases

Inclusion body disease (IBD) is a serious viral disease of pythons and boas caused by a reptarenavirus. While pythons commonly show signs of infection, boas may carry this virus for more than a year without showing obvious signs of infection. The signs vary widely. This disease may affect the respiratory or digestive tract, but it is generally associated with the nervous system.

Affected snakes cannot right themselves when placed on their backs, may appear to be “star gazing”, or in severe cases, may be paralyzed. IBD is contagious from snake to snake and is typically fatal. Several other viral diseases such as nidovirus and paramyxovirus have been shown to cause serious disease in constrictor-type snakes. In most cases, these viruses cause damage to the snake’s immune system, making them susceptible to bacterial infections.

How can I tell if my snake is sick?

Signs of disease in snakes may be specific for a certain disease, such as a cheesy-type discharge in the mouth of a snake with stomatitis, or non-specific, such as lack of appetite and lethargy, which can be seen with many diseases. Any deviation from normal is a cause for concern and should be evaluated by your veterinarian as soon as possible. Mites and ticks are visible to the human eye but are often buried under the scales on the underside of a snake’s body, especially the head.

How are snake diseases treated?

  • Infectious stomatitis usually requires aggressive treatment with injectable antibiotics, removal of the buildup of pus and/or mucus, and rinsing the mouth with antibiotic solutions. It may take weeks to resolve the infection. Hospitalization may be necessary. The snake's cage will need a deep cleaning and other snakes housed in the same cage must be examined as soon as possible. A bacterial culture may be submitted and testing for underlying viral diseases may be recommended.
  • For parasitic infections, deworming medications are injected or administered orally. The type of parasite determines the drug required. Some parasite problems, such as cryptosporidiosis, may be difficult or impossible to treat. Mite and tick infestations require treatment by a veterinarian familiar with snake parasites. It is critical to deep clean the environment, perches, and bedding. Mites are notorious for hiding under the lip of gall aquariums and in hide huts.
  • Dermatitis can be managed with proper environment and hygiene. Oral and injectable antibiotics, as well as topical therapy, are needed if this disease is advanced.
  • Respiratory infections in snakes can be due to bacteria, parasites, fungi, or viruses, and environmental irritants can cause nasal discharge occasionally. Your veterinarian may recommend X-rays, blood tests, and cultures of nasal or oral discharge to determine the cause. Treatment involves oral or injectable antibiotics and occasionally nose or eye drops. Severely ill snakes require intensive care, including fluid therapy, nebulization therapy, and force feeding in hospital.
  • Septicemia is a true emergency that requires aggressive treatment in the hospital. Antibiotics, fluid therapy, and force feeding are needed to attempt to save the snake.
  • Snakes with inclusion body disease are typically euthanized, as there is no cure. New animals must be strictly quarantined to avoid potential disease spread. Boas and pythons should be housed separately, as seemingly normal boas may carry this potentially fatal infection and may spread it to more susceptible pythons. 

Any of these diseases can be severe enough to cause a loss of appetite and lethargy. Seek immediate veterinary care if your pet snake shows any deviation from normal.

Related Articles