Pneumonia in Snakes
Dr. Ray Wak
Snakes with pneumonia may have nasal discharge, gurgling, bubbling or open mouth respirations. They are usually anorexic and often rest with their heads elevated. You might see the snake rubbing his nose on the cage walls to clear discharge out of his nostrils or gasping for air. Because of the location of the glottis (opening of the windpipe) on the floor of the mouth, snakes with mouth infections, sinus infections or eye infections are more prone to develop pneumonia. A number of parasites including lung mites (Entonyssus spp), lungworms (Rhabdias spp) and pentastomids, live in or migrate through the lungs of snakes. These may damage the lung tissue predisposing the snake to pneumonia.
An ophidian paramyxovirus (Fer-de-Lance Virus) damages lung tissue. Snakes infected with this virus frequently die from secondary bacterial pneumonia. Currently there is no commercially available vaccine for ophidian paramyxovirus.
Most cases of pneumonia in snakes are caused by bacterial infections of the lung. The bacteria may be aerobic (living in air) or anaerobic. Generally the bacteria that cause pneumonia are gram negative on cytology stains. Although primary fungal pneumonias are rare, secondary fungal infections are not uncommon.
Poor husbandry conditions such as low cage temperatures and inadequate nutrition predispose snakes to developing pneumonia.
The diagnosis of pneumonia in snakes starts with a good history and physical exam. The history often includes an episode of decreased cage temperature or exposure to pathogens. The physical exam should include looking at the nostrils, a thorough oral exam and auscultation (listening to the heart with a stethoscope). Although auscultation is frequently unrewarding, it should be done, because positive findings are highly significant. Thin bodied snakes can be trans-illuminated to check for lung mites. Other tests may include:
A fecal exam and tracheal or oral swab stained for cytology (examination under a microscope) or examined for the presence of ova (eggs) or parasites.
A blood sample to evaluate the blood cell counts and cell differentials. An elevated heterophil count may be associated with a bacterial infection. A serum or plasma chemistry panel may be obtained to screen for involvement of other body systems. A blood sample may be submitted to a special lab to check for antibodies to paramyxovirus.
Bronchoscopy. With the snake anesthetized, a very small fiberoptic scope is either slid down the trachea (windpipe) or placed into the lung. This allows visualization of the trachea and lung as well as the collection of samples directly from the site of infection. If lung mites are present, they may be directly observed through the scope. Samples may be collected for gram staining (identifies the type of bacteria), bacterial or viral culture or histopathology.
A lung wash is done to obtain a fluid sample from the lung. In this test, a small amount of sterile fluid is injected into the lung and then retrieved. The fluid can then be looked at under the microscope (cytologic exam) or cultured.
A radiograph is done to evaluate the lungs. Due to the difference in lung structure between snake and mammalian lungs, radiographs are frequently not as helpful for diagnosing pneumonia as they are in mammals.
Snakes with pneumonia need to be treated quickly and aggressively. Pneumonia is a serious disease in snakes and may cause death if not promptly treated. They should be physically separated from other reptiles as many causes of pneumonia are contagious to other snakes. The treatment of pneumonia in snakes is dependent upon its cause.
Bacterial causes. Pnuemonias caused by bacteria or with secondary bacterial infections are frequently treated with antibiotics. These antibiotics may be given orally (in the mouth) or by injection. It is important to give the prescribed amount of antibiotic at the time interval indicated by your veterinarian.
Snakes with pneumonia may be dehydrated and some antibiotics are more likely to cause side effects if the snake is dehydrated so additional fluids may be prescribed for the snake. These fluids may given orally or under the skin. Consult your veterinarian if you are unsure how to give the fluids.
Viral causes. Viral infections can rarely be treated directly with drugs. In most cases of viral pneumonias supportive care is given to the snake while he attempts to clear the infection. Supportive care may include increasing the cage temperature, nutritional or fluid therapy, and frequent removal of nasal or oral exudates. Some snakes with pneumonia may benefit from additional vitamin C.
Parasitic causes. Some parasites live in or migrate through the lungs. As these can predispose the snake to pneumonia, an anthelmintic (de-wormer) may be prescribed by your veterinarian.
Home Care and Prevention
Often, increasing part of the cage environment to the upper end of the preferred optimal temperature range will help the snake fight off the infection. You should monitor the animal closely for any signs of heat stress. In addition, do the following:
Gently clean any discharge from the nostrils of the snake. A cotton tipped applicator dipped in warm water may help. You may need to carefully clean any discharge from around the glottis. Have your veterinarian show you how to do this. Be careful not to be bitten and do not damage the snake's teeth.
Depending on the cause of the pneumonia, your veterinarian may prescribe an oral or injectable antibiotic and additional fluids. Administer all medications according to your veterinarian's instructions.
Since snakes cannot cough, it is difficult for them to remove mucous and discharges from their lungs. In some cases, nebulization or placing the snake's cage in a warm steam filled room, may help break up and clear the exudate in the trachea and glottis. Sometimes draping the snake over a rod so that the head is lower than the lungs can facilitate drainage of fluids from the lungs. For snakes that do not appear to be stressed by handling, encouraging the snake to climb downwards (from hand to hand or down stairs) may also help the snake to clear excess discharge.
Observe your pet's general activity level and interest. If these become worse, contact your veterinarian.
Schedule regular veterinary visits to monitor the condition.
The best way to prevent pneumonia is to maintain a healthy environment for your pet. Many respiratory infections can be prevented by good nutrition and husbandry practices. In most cases, providing a range of environmental temperatures that include the upper end of the preferred optimal temperature range will help prevent respiratory infections.
Whenever possible, all new pet reptiles should be quarantined for 90 days prior to exposing current pets to the new animals. Examine the animals closely several times during the quarantine period to make sure that they are healthy. Have your veterinarian perform a quarantine exam on all new arrivals prior to exposing your current pets to the new arrival.
Have your pet reptile examined on a regular basis by your veterinarian to make sure that he is healthy and does not have a respiratory infection. Treat any parasites found on routine examination, as some parasites potientially damage the lungs, thus making respiratory tract infections more likely.