Snake Diseases

Infectious stomatitis (‘mouth rot’) is an infection of the mouth that appears as pinpoint haemorrhages on the gums or an excessive amount of thick mucus, possibly containing blood, or pus resembling cottage cheese, in the mouth and at the inside edge of the front of the mouth. In severe cases, the snake has a severely swollen mouth, teeth may fallout, may open mouth breathing, and will refuse eating due to the pain caused by stomatitis. Stomatitis may not be a primary disease but may be secondary to an injury to the mouth or to husbandry issues such as poor nutrition, improper environmental temperature or humidity, or overcrowding.

Infectious stomatitis, infection and inflammation of the tissue lining the mouth, is seen in snakes, lizards, and turtles. Early signs include tiny, purplish red spots in the mouth. Diseased tissue develops along the rows of teeth as the condition worsens. In severe cases, the infection can extend into the upper and lower jaw bones. Bacteria that are commonly found in the mouth are the most frequent causes of stomatitis. Respiratory or gastrointestinal infection may develop if stomatitis is not treated promptly. Treatment involves surgical removal of dead tissue from the mouth, cleaning with an antiseptic solution, antibiotics, and supportive care. More extensive surgery may be required in severe cases. Vitamin supplementation, especially with vitamins A and C, has been suggested but may not change the course of disease.

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 that may be 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, septicaemia (a bacterial infection in the blood), and death. Snakes kept in too dry conditions, 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.

Inclusion body disease (IBD) is a very serious viral disease of pythons and boas. 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 a lot; although this disease may affect the respiratory or digestive tract, it is generally associated with the nervous system. Affected snakes cannot right themselves when placed on their backs, may appear to be ’star gazing’, and may be paralyzed. IBD is contagious from snake to snake and is typically fatal.

Snakes have a unique respiratory tract. Most snakes have only one functional, simple lung (usually the right lung; the left one is reduced in size or completely absent). Boas and pythons are the exception to this, with two lungs. Snakes do not have a diaphragm 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. Viruses, fungi, and parasites can also cause respiratory disease. Snakes with respiratory infections may have excess mucus in their mouths, nasal discharge, lethargy, loss of appetite, wheezing, and may make ‘gurgling’ sounds or open mouth breathe.

“Most respiratory infections in snakes are caused by bacteria and may occur in conjunction with mouth rot.”

More on IBD: Boas and pythons are most commonly affected by inclusion body disease (IBD), which was originally thought to be caused by a retrovirus but recently confirmed as a reptarenavirus. Boas are considered a more typical host because so many are infected, and they can harbour the virus for months to years with few to no clinical signs. Early signs, possibly precipitated by any factor causing immunosuppression, include a history of unthriftiness, anorexia, weight loss, secondary bacterial infections, poor wound healing, dysecdysis, and regurgitation. In essence, IBD should be considered in every sick boa. Typical findings in the acute phase of the disease include leucocytosis and a normal chemistry panel. As the disease progresses, WBC counts tend to decline to subnormal levels. Blood chemistry results vary depending on how debilitated and dehydrated the boa becomes, but organ damage may occur. As the disease becomes chronic, some boas exhibit neurologic symptoms ranging from mild facial tics and abnormal tongue flicking to failure of the snake to right itself when placed in dorsal recumbency and severe seizures.

Pythons are thought to be a more acutely affected host for the reptarenavirus, because the course of disease is more acute and neurologic symptoms more often profound, with most pythons presenting with severe neurologic disease. Although the active disease can linger for months or more in boas, most pythons die within days or weeks of the onset of clinical signs.

Exposure to reptarenaviruses appears to be due to a transfer of body fluids. Breeding, fight wounds, faecal/oral contamination, and snake mites have been implicated as common ways of transfer. A tentative diagnosis is based on history and clinical signs. Blood work varies depending on the stage of the disease, but few diseases in snakes will cause such increased WBC counts in the early stages. On blood smears, inclusion bodies are frequently found in the cytoplasm of leukocytes. A definitive diagnosis is obtained by PCR and biopsy of internal tissues in which the characteristic eosinophilic inclusion bodies are found, e.g. the liver, kidney, oesophageal tonsils, and stomach.

IBD is not curable, and many owners choose euthanasia. However, individuals may elect to isolate their snakes and treat with supportive and palliative measures. It is essential to educate owners not to sell infected specimens or their offspring, because this has caused the disease to spread worldwide.

Septicaemia is a condition in which bacteria and the toxins they produce proliferate in the blood stream and other body organs. Snakes with septicaemia 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.

Septicaemia, caused by bacteria in the blood, is a common cause of death in reptiles. The disease affects the whole body and may result from trauma, an abscess, an infestation of parasites, or environmental stress. Death may be sudden or occur after long term signs of illness. Common signs are trouble breathing, lack of energy, convulsions, and loss of muscle control. Reptiles with septicaemia may develop small, purplish red spots on the belly skin; chelonians may have reddened plastrons. Keeping a reptile’s environment clean and well maintained can reduce the risk of septicaemia. Affected reptiles should be isolated and treated with antibiotics.

Retroviruses have also been found in Russell vipers, corn snakes, and California kingsnakes in association with malignant tumours. A retrovirus isolated from a sarcoma in a Russell viper was designated as viper virus. A related virus was isolated in a corn snake from a rhabdomyosarcoma and designated corn snake retrovirus.

Adenoviruses have been implicated in fatal hepatic or GI diseases in:

• snakes (gaboon vipers, ball pythons, boa constrictors, rosy boas, and rat snakes)
• lizards (Jackson chameleons, savannah monitors, and bearded dragons)
• crocodilians

In bearded dragons, the route of transmission appears to be faecal/oral contamination. Clinical signs are more commonly noted in juvenile dragons but can affect adults, usually to a lesser extent. Signs are vague and include lethargy, weakness, weight loss, diarrhoea, and sudden death. The morbidity is high in young bearded dragons, but survival is increased with supportive care. Fluid administration, force feeding, and antibiotics for secondary infections may be useful.

The signs of disease in bearded dragons are vague and similar to those caused by coccidia and nutritional disorders, so diagnostic confirmation is important. Characteristic intranuclear inclusion bodies are found in several internal organs, primarily the liver. When working with a large breeding group of lizards, it is practical to sacrifice a failing specimen to make a diagnosis. Premortem diagnosis can be accomplished by liver biopsy. Identification of adenovirus by PCR from fresh faeces may indicate shedding and infection but not necessarily disease.

Recovered lizards should be quarantined for at least 3 months. Duration of viral shedding after recovery is unknown, so owners should be discouraged from selling or trading previously infected animals.

Adenoviruses may cause fatal liver or digestive tract diseases in certain snakes (Gaboon vipers, ball pythons, boa constrictors, rosy boas, and rat snakes), lizards (Jackson’s chameleons, savannah monitors, and bearded dragons), and crocodilians. In bearded dragons, the adenovirus appears to be transmitted by faecal-oral contamination (faeces coming into contact with the mouth). Signs of infection are more common in younger dragons but can also affect adults, usually to a lesser extent. The signs are vague and include lack of energy, weakness, weight loss, diarrhoea, and sudden death. The illness rate is high in young bearded dragons, but supportive care (fluid administration and assisted feeding) and antibiotics to treat secondary bacterial infections can increase survival.

The signs of adenovirus infection in bearded dragons are similar to those caused by coccidia and nutritional disorders. The diagnosis of adenovirus infection can be confirmed with a liver biopsy.

Lizards that have recovered from the infection should be quarantined for at least 3 months. The length of time a lizard can infect other lizards after recovering is unknown, so you should not plan to sell or trade a previously infected animal.

Ferlavirus (Paramyxoviridae) infections have been reported in various viperid snakes but have also been reported in nonvenomous snakes and lizards. This highly contagious virus causes predominantly respiratory signs; transmission appears to be from respiratory secretions. Secondary bacterial infections are common because of the severe inflammation initiated by the virus, and it is not unusual to note nasal discharge, open-mouth breathing, caseated pus in the oral cavity, and laboured breathing. Neurologic involvement, including tremors and opisthotonos, is occasionally noted.

Endoscopic biopsies and post-mortem samples of lung can be submitted to detect viral particles by histology and electron microscopy. A hemagglutination inhibition test is available to measure antibodies against ophidian paramyxovirus in zoos and private collections; a positive titer should be used as a screening tool to help eliminate infected animals and prevent carriers from entering noninfected collections. PCR detection is also available.

There is no specific treatment, but supportive care and antibiotics may prove useful. Affected specimens should be isolated and strict hygiene practices followed. Although a vaccine is under development, it is currently not effective.

Recently, a nidovirus (Coronoaviridae) has been reported as a cause of pneumonia and stomatitis in pythons and boas. Detection of the virus is possible by PCR of oral swabs and tracheal washes.

Iridoviruses have been reported in various chelonians, snakes, and lizards. An iridovirus was found in a Hermann’s tortoise, which died without prior signs of disease. Progressive anaemia in Australian geckos has been linked to an iridovirus. Clinical signs range from none to stomatitis, rhinitis, conjunctivitis, tracheitis, oedema, and cutaneous abscessation. In some cases, the recovered iridoviruses have been closely related to amphibian ranaviruses. Although the clinical importance of several of these viruses remain unclear, iridoviruses deserve close attention, especially in chelonians.

The stress of captivity coupled with a closed environment makes reptiles susceptible to heavy infestations of parasites with direct life cycles—that is, parasites that require only 1 host species to complete their life cycle. Every effort must be taken to rid reptiles of parasite burdens and to rid the environment of intermediate host species (like insects).

Treatment should be attempted when evidence of an infestation of parasites is found. Drugs called anthelmintics are usually needed to eliminate internal parasites. Many different anthelmintics (dewormers) are available. Your veterinarian can prescribe the one considered most effective for the particular parasite involved.

Roundworms of the stomach (stomach worms) are seen in lizards and can cause stomach ulcers in severe infestations. Numerous snakes are infected by a hookworm that lives in the upper gastrointestinal tract and causes wounds at sites of attachment. Large swellings caused by the inflammatory response to this hookworm can cause intestinal obstruction.

Parasites known as ascarids also frequently infect reptiles. Severe tissue damage and death may occur in infected snakes. Snakes infected with ascarids may regurgitate partially digested food or adult worms and may have no appetite. Infection may cause inflammatory swellings in the gastrointestinal tract. These swellings may abscess and perforate the intestine.

Many other species of roundworms may be found on examination of a reptile’s faeces. Prey animal parasites (like mouse pinworms) that do not cause disease in reptiles may also be seen in a reptile’s faeces after the reptile consumes an infected animal.

Protozoa are single-celled organisms; some cause disease in animals. Entamoeba invadens is the most serious disease-causing protozoan of reptiles. Signs of infection are loss of appetite and weight, vomiting, mucus-containing or bloody diarrhea, and death. The disease may spread quickly in large snake collections. Plant-eating reptiles appear to be less susceptible than meat-eating ones. Several kinds of reptiles that seldom become affected or die can serve as carriers; these include garter snakes, northern black racers, and box turtles. Most turtles are resistant, although giant tortoises are susceptible. Other resistant species include eastern king snakes, cobras (possibly as an adaptation that allows them to eat other snakes), and crocodiles. Susceptible snakes include most boas, colubrids (a family that includes king snakes, garter snakes, and racers), elapids (a family of venomous snakes including coral snakes and mambas), crotalids (the pit viper family, including copperheads and rattlesnakes), and other vipers. This protozoan is transmitted by direct contact with the cyst form. Diagnosis is made by examining faeces or tissue samples for the protozoan.

An antiprotozoal drug is usually prescribed for treatment. To help prevent transmission among reptiles, turtles and snakes should not be housed together. The potential for this disease to be passed on to humans should not be taken lightly, and strict sanitation and hygiene measures should be observed.

Cryptosporidiosis is infection caused by protozoa of various Cryptosporidium species. It can cause regurgitation, marked weight loss, and long-term weakness. In snakes, the organism affects the lining of the digestive tract, causing thickening of the stomach lining and loss of normal digestive motion of the stomach. A veterinarian may be able to feel a mass in the stomach area. Radiographs or an examination using an endoscope may reveal thickening of the stomach lining. Many lizards, including Old World chameleons and savannah monitors, are affected primarily in the intestine. Cryptosporidiosis is diagnosed with tests of the faeces or regurgitated food or by biopsy of the stomach. Several treatments have been suggested, but most do not work consistently. Intensive supportive care will often stabilize and help prolong the life of the affected reptile.

Cryptosporidiosis can be transferred from animals to humans. However, Cryptosporidium species typically found in reptiles appear to rarely infect humans.

Snakes can develop abscesses below the spectacle (eye cap), the clear protective covering over the eye. Other reptiles can develop conjunctivitis, inflammation of the membranes around the eye. The severity of conjunctivitis ranges from mild to severe (involving all the tissues around the eye and the eyeball itself). It may result from the spread of infectious stomatitis from the mouth. Conjunctivitis in turtles and lizards without spectacles can be treated with topical eye ointment. Snakes and lizards with spectacles need surgery to drain the abscess and flush the eye with an antibiotic solution. Some affected reptiles, especially turtles, may need supplemental vitamin A.

Secondary renal hyperparathyroidism is a kidney disorder that occur in adult reptiles. It is associated with high levels of phosphate and low levels of calcium in the blood, calcification (hardening) of soft tissues, and loss of calcium from bones. Diagnosis can be suspected based on the history, radiography, and blood tests, although a definitive diagnosis requires demonstration of poor kidney function or kidney damage seen on a biopsy of the kidney. Treatment options are limited because of the difficulty in correcting kidney damage.

Stargazing is a sign of some nervous system disorders in snakes and other reptiles. Stargazing describes a twisting of the neck that makes the animal appear to look upward (toward the stars). Other signs of nervous system disorders include mental dullness, abnormal posture, seizures, and inability to move normally. One of the most common causes of stargazing in boa constrictors and pythons is inclusion body disease, which is caused by a viral infection.

Stargazing can also be caused by exposure to excessive heat, head injuries, toxins, and infections caused by bacteria or other organisms. Bacterial meningitis or encephalitis can result from bacterial infections that move into the bloodstream and penetrate nervous system tissue. The outcome of neurologic disease varies depending on the cause, but the outlook is generally poor. Antibiotics are usually necessary in cases of bacterial infection.

Reptiles with poor appetites may require assisted feeding. This is a process that is best directed by your veterinarian because feeding a malnourished reptile with severe dehydration can lead to additional health problems. Initial feedings should replace fluids and electrolytes. Signs of dehydration include loose skin or sunken eyes.

A dehydrated reptile can sometimes be encouraged to drink by allowing it to bathe in shallow water within an enclosure kept within the preferred temperature range for that species. Dehydrated turtles and tortoises may also be able to absorb water through the cloaca while bathing. However, dehydrated reptiles may need fluids administered by a veterinarian through injection or a stomach tube.

A malnourished reptile might have protruding bones and a gaunt appearance, but signs of malnutrition and dehydration may not be easy to see. Some malnourished animals require assisted feeding, which should be done only under the direction of a veterinarian to reduce the possible risks.

If your reptile is not eating well, environmental factors such as temperature, light, and humidity should be set at the proper levels for that type of reptile. Reptiles cannot process fluids and nutrients properly if environmental conditions are not optimal.

Gout is seen in all orders of reptiles. It occurs when the level of uric acid in the blood is too high. Two forms of gout have been reported. Visceral gout affects the organs, and articular gout affects the joints. Radiographs may show mineralized deposits from uric acid in the affected organs and joints. Visceral gout can be due to too much protein in the diet (primary visceral gout) or to other causes such as dehydration or kidney damage (secondary visceral gout). Gout can be very painful, causing discomfort to the point that some reptiles refuse to move, eat, or drink.

Primary visceral gout is treated by correcting the diet. Secondary visceral gout is treated by trying to correct the underlying problem. Drugs that have traditionally been used to treat gout in humans may be effective in reptiles if the diagnosis is made early. However, the outlook for recovery is poor in advanced cases. Medical treatment usually must be long-term because signs of gout often occur again if treatment is discontinued. Euthanasia should be considered in reptiles that appear to be in pain and have no appetite.

Respiratory infections, including pneumonia, are common in reptiles and can be caused by parasites of the respiratory system or the whole body, unfavourable environmental temperatures, unsanitary conditions, other diseases, malnutrition, and vitamin A deficiency. Open-mouth breathing, discharge from the nose, and difficulty breathing are frequent signs. Septicaemia (widespread infection in the bloodstream) may develop in severe or prolonged cases. Treatment consists of improving environmental factors (such as cleanliness and temperature) and starting antibiotic therapy. A veterinarian will be able to advise you on the proper antibiotic treatment. Reptiles with respiratory infections should be kept at the middle to upper end of their preferred temperature range. Increased temperatures help stimulate the immune system and also help move respiratory tract secretions. Turtles with pneumonia often have an underlying vitamin A deficiency. Turtles treated for pneumonia may not improve completely until they have been supplemented with vitamin A.

Paramyxovirus

Paramyxovirus infections are more common in vipers than other snakes but have also been reported in nonvenomous snakes. This highly contagious virus most often causes respiratory system problems. Secondary bacterial infections are common, and affected animals may have discharge from the nose, open-mouth breathing, dried pus in the mouth, and laboured breathing. Neurologic signs, such as tremors and abnormal posture, are sometimes seen. The virus appears to be passed from one animal to another through respiratory tract secretions.

A snake with a respiratory infection that does not respond to typical treatments (including antibiotics) may have a paramyxovirus infection. Blood tests can be used to screen animals for infection and prevent carriers from entering noninfected collections. There is no specific treatment, but supportive care and antibiotics may be helpful. Affected snakes should be isolated and strict hygiene practices used.

Dystocia

(Egg Retention) Sterilization is rarely performed in reptiles, and therefore reproductive disease remains a common problem. In egg-laying reptiles, eggs (with variable levels of shell mineralization) may be retained, whereas in species that bear live young, unfertilized eggs or foetuses may be seen. In some cases, abnormal ovarian follicles may also be present. Dystocia is generally not a sudden event as in mammals or birds, and reptiles may retain eggs or foetuses for weeks or even months after the normal timing of laying/birth. If it is not known when the reptile was bred, this can make it hard to tell the difference between a normal pregnancy and dystocia in otherwise clinically healthy reptiles. Metabolic disease or infection can worsen the issue. In general, your veterinarian will be able to make the diagnosis after examining your reptile and performing diagnostic imaging, especially radiography and ultrasonography. Blood tests may also help identify infections or metabolic diseases, such as hypercalcemia (see nutrient requirements).

Unless there is evidence of short-term disease, medical management may be tried, although it frequently fails. Improvements in husbandry (especially provision of solitude and a suitable substrate), corrections of any metabolic diseases, and hormonal treatments to induce labour may be helpful. In most cases, surgery is necessary after medical stabilization and typically requires removal of the reproductive organs.

Vent Prolapse

Several organs, including the cloaca, colon, oviduct, hemipenes/phallus, and (if present) bladder may prolapse through the vent of reptiles. Common causes include dystocia, breeding trauma, inflammation of the cloaca, infections, metabolic disease, bladder stones, kidney disease, cancer, or any space-occupying mass within the abdomen that causes straining to defecate. It is important to identify the prolapsed organ, because some (e.g., phallus/hemipenes) can be amputated, whereas others (e.g., cloaca, colon, bladder) cannot. Your veterinarian will gently clean the prolapsed organ and attempt replacement. However, it is also important to determine the cause to prevent recurrence.

Prolapses of the hemipenes and phallus can be amputated surgically; this will make the animal infertile. If the prolapsed tissue is viable and can be replaced, surgery can be performed to hold it in its usual place. If the tissue is dead, then careful surgery is required to remove the affected tissues and reconnect the living sections at each end.

Reptiles are prone to a variety of skin diseases and disorders. Good sanitation practices such as cleaning the enclosure regularly, providing fresh water, and removing uneaten food can help prevent infection and parasite infestation.

Abscesses

Abscesses are pus-filled sores, often accompanied by inflammation, that are usually caused by bacterial infection. They are seen in all orders of reptiles. Abscesses are often caused by bite wounds, other injuries, or poor environmental conditions. Abscesses under the skin appear as small lumps or swellings. Other conditions that may look like abscesses are parasitic infections, tumours, and hematomas (swellings filled with blood). A number of species of bacteria, often more than one kind at a time, can be present in abscesses in reptiles. Small, localized abscesses should be surgically removed to avoid recurrence, which happens frequently. Larger abscesses should be surgically opened and drained. Appropriate antibiotics may be needed.

Dysecdysis

Dysecdysis refers to incomplete or abnormal shedding of the skin. Low humidity, skin parasites, nutritional deficiencies, infectious diseases, lack of suitable abrasive surfaces, and decreased thyroid function may contribute to an abnormal shed. Spectacles (eye caps), which are the clear protective layer over the eyes, or circular bands on the tail or toes may not shed properly and may be retained. Retained spectacles are best treated by applying an eye ointment for several days until the spectacle either falls off or can be carefully and gently removed with fine forceps. Be patient; eye caps should never be forced off because of the possibility of damaging the new one underneath.

Retained skin is best treated by soaking the reptile in warm (77°F to 85°F [25°C to 29°C]) water for several hours and then pulling gently with a gauze sponge. A humidity chamber also works well. This can be as simple as a 10-gallon aquarium with an under-tank heater in which wet bath towels are placed. The top can be covered with a light cloth to increase humidity levels, but excessive heat must be avoided and can be relieved by allowing more ventilation. It is easier to prevent than to treat an abnormal shed, so make sure that your reptile is free of disease and parasites, eats a diet appropriate for its species, is kept at the correct humidity level, and has abrasive surfaces available to help it shed.

Parasites that live on the skin can be a problem with wild-caught and newly acquired reptiles. Infestations are best prevented by thorough examination and a period of quarantine for all new animals entering a collection.

Mites are distributed worldwide, and most species of reptiles are affected. Mites can cause reduced energy and, in heavy infestations, death by anaemia (loss of red blood cells). Mites may also transmit disease-causing organisms from other infected animals. The skin of affected reptiles appears coarse, and dysecdysis may occur. Most mites are tiny (less than 1.5 millimetres long) and are often found around the eyes, skin folds on the face or neck, or any other indentation on the body.

Mites are visible to the naked eye but are hard to see in small numbers. If mites are suspected, placing the reptile on a piece of white paper and gently rubbing it may cause mites to fall off and be visible. Affected reptiles often spend a great deal of time soaking in water to drown the mites. If you examine the water dish, you might see the drowned remains of mites.

There are many methods of treatment. In all cases, cages should be cleaned thoroughly, and you should throw away substrate materials, branches, and disposable cage furniture. Newspaper bedding should be used until treatment is completed to help with frequent cleaning and to get rid of sites where mites could lay eggs. A veterinarian can tell you the type of mites your reptile has and provide advice on eliminating them from your pet and its enclosure (such as recommending a safe insecticide).

Any enclosure in which insecticide is used should be well ventilated, and any water containers should be removed while spraying insecticide and replaced when the spray has dried. Do not use any product without consulting your veterinarian; some are not safe for all reptiles.

Ticks are frequently found on reptiles and have been associated with many diseases. Heavy infestations may result in anaemia (too few red blood cells) due to loss of blood. Certain ticks may cause paralysis, with muscle wasting at the site of the bite. Ticks can be removed with forceps (tweezers) or killed by insecticides recommended by your veterinarian. If you remove a tick manually, wear gloves to avoid exposure to diseases it may be carrying. Animals with ticks may require antibiotics to treat infections associated with multiple skin bite wounds and possibly transmission of disease-causing bacteria.

Scale rot (ulcerative or necrotic dermatitis) is seen in snakes and lizards. Humidity and unclean environments appear to be the main factors that cause this condition. Moist, contaminated bedding allows bacteria and fungi to multiply. When coupled with exposure to faeces, these organisms can cause skin sores. Secondary infection with other bacteria may result in septicaemia (blood infection) and death if untreated. Reddening of the skin, areas of dead skin, skin sores, and skin discharge are common signs. Although sores are sometimes caused by skin injuries, they more often develop from within. This is the case with classic necrotic dermatitis in the ball python, which can develop even when animals are kept under ideal conditions. The disorder starts with bleeding into scales, followed by pustules (small, raised, pus-filled bumps like pimples) that eventually progress to ulcers. Treatment with antibiotics and excellent hygiene are essential.

Blister disease is an early stage of scale rot. The skin develops pustules or blisters that may heal without progressing to ulcers if treatment is started early. Low-grade heat injury may look like blister disease if it causes fluid-filled blisters.

Excessively high humidity, low environmental temperature, existing disease, malnutrition, and other stressors may make reptiles more likely to develop fungal diseases. Little is known about the course of fungal infections that affect the whole body and develop over a long period, but maintaining good sanitation and nutrition reduces the frequency of these infections. Antifungal drugs may be used to treat fungal infections that have spread through the whole body, but reports of successful treatment in reptiles are few. For fungal infections that are limited to one area, surgical removal of the infected tissue followed by local wound treatment may be helpful. Basidiobolus species, which can cause disease in mammals, have been found in the faeces of healthy reptiles.

The most frequent sites of fungal infection in reptiles are the skin and respiratory tract. Slow-healing internal sores developing on gastrointestinal tissues have been associated with some fungal infections. Fungal infections can also cause disease of the liver, kidneys, and spleen. Few signs other than weight loss may be seen before death. Animals may continue to eat until a few days before death.

Flagellates (a type of protozoal microorganism), especially Hexamita species, can cause urinary tract disease in turtles and tortoises and intestinal disease in snakes. An anthelmintic or antiprotozoal drug is usually prescribed for treatment.

Infection of the cloaca (the passage for both urine and faeces in reptiles) can be caused by kidney stones or other hard accumulations in the lower intestine, urinary tract, or reproductive passages. It is characterized by swelling and bloody discharge from the cloaca. Mineral deposits may form when vitamin or mineral imbalances are present in the diet. These deposits should be manually removed by a veterinarian and followed by dietary correction. Abscesses around the cloaca can extend to other parts of the body and can cause urinary or genital tract infections. Prompt and thorough treatment, including surgery to remove damaged tissue, local wound treatment, and appropriate antibiotics, is required. Your veterinarian may need to examine faeces from your reptile to identify whether the infection is caused by parasites.

Internal Abscesses

Abscesses in internal organs may result from blood infection (septicaemia). Abscesses of the female reproductive system are common and may lead to an infection of the abdomen. In this case, surgery is required because treatment with antibiotics alone is rarely successful.

Disease-causing flatworms (trematodes) infect the arteries and veins of turtles and the mouth, respiratory system, and urinary system of snakes.

Tapeworms are found in all orders of reptiles but are rare in crocodilians. The complex life cycle of tapeworms and the need for intermediate hosts limit the number of cases in captive reptiles. When present, tapeworm segments may be found in the cloaca, or tapeworm eggs may be found in faeces. The infective larvae of some tapeworms may cause swellings in the tissue beneath the skin. These larval stages may be removed surgically.

Roundworms (nematodes) are found in all orders of reptiles. Examples of nematodes are pinworms and hookworms. These parasites can inhabit the intestinal tract, respiratory tract, or body wall of reptiles. They can sometimes be found in the faeces. Infections often are mild but may lead to more serious diseases, such as pneumonia. In severe cases, death may result.

Some roundworm larvae may be able to penetrate the skin. Good sanitation practices to remove parasites from the environment help reduce parasite burdens in captive reptiles.

Skin sores caused by the spirurid worm (Dracunculus species) may occur in reptiles. Numerous species of spirurids infect the body cavity and blood vessels. These worms are less common in captive-bred reptiles or in reptiles that have been in long-term captivity.

Tongue worms (pentastomes) are found in a variety of reptiles. These worms may or may not cause signs of disease. Infections are occasionally associated with signs of pneumonia, but these parasites can inhabit any tissue, and signs will vary according to the path of their migration through tissues. Tongue worms were first noticed in venomous tropical snakes and have also been seen in other reptiles. Treatment with the usual drugs (anthelmintics) often fails to eliminate these worms. In some cases, it may be possible for your veterinarian to use an endoscope to locate and mechanically remove all the adult worms. Recognition of these infestations is important because tongue worms are thought to present a risk of infection to humans.

Mycobacterial infections are often associated with chronic wasting (a gradual loss of body condition). These infections generally affect the lungs of turtles and tortoises. Lizards, snakes, and crocodilians often develop small growths on their internal organs. The drugs required to fight these infections cause liver damage in reptiles, and their longterm use is unlikely to be safe.

Tumours are much more common in reptiles than previously thought. In addition to spontaneously developing cancerous (neoplastic) diseases, tumours have been associated with parasites and certain viruses. Tumours in reptiles are usually easily identified through various tests performed by a veterinarian. Once tumours are identified, treatment protocols similar to those used in other animals could be adapted. Your veterinarian will be able to recommend the appropriate treatment.

Ophidian paramyxovirus (OPMV), also called Fer-de-Lance virus of reptiles (FDLV), is an important viral pathogen of snakes, principally Viperidae and it has also been isolated from Elapidae, Colubridae and Boidae. The natural host for OPMV is unknown but may be a non-viperid. Disease may be associated with decreased immunocompetence. Transmission may be by droplet, fomites and vectors such as mites. Congenital infection may be involved.

Examination

Anorexia may be seen several weeks before presentation. Clinical signs are often related to the respiratory system. Presentation is frequently a moribund snake, although the progression may be chronic. There may be a discharge from the glottis that is sometimes bloody (haemorrhagic pneumonia). Central nervous system signs (including writhing, torticollis, loss of righting reflex) are occasionally seen. Chronic paramyxovirus shows clinical progression from mild respiratory disease to severe respiratory disease and pneumonia, followed by progressive neurologic disease.

Consider paraxmyxovirus in snakes with the following clinical signs:

• Emaciation
• Loss of muscle tone
• Unwillingness to move
• CNS signs including head tremors, stargazing)
• Seeking heat
• Recurring unresponsive bacterial or fungal pneumonia
• Mucoid diarrhoea
• Malodorous stools
• Distended bowel
• Severe protozoal infections

Therapy

There is no specific treatment for snakes showing clinical signs of OPMV infection. Antibiotics are indicated because most affected snakes die with gram-negative respiratory tract infections.
Infected snakes should be isolated. Snakes suspected to be infected should remain in isolation until definitive diagnostic tests have been carried out. Reptiles that have been in direct or immediate indirect contact should be placed in isolation and serologically tested immediately with repeat testing in 4-6 months time.

Prevention

The best control is a sound preventative medicine programme. All new specimens should be quarantined for ninety days. Hygiene is very important because of the possibility of spread by fomites and mites. Geriatric snakes may be more susceptible to paramyxovirus than young conspecifics. Modified-live and inactivated vaccines have had mitigated the spread of paramyxovirus in birds and mammals, however there is currently no vaccine available for protecting snakes against OPMV.