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Lower respiratory tract disease

Synonym(s): RI, Pneumonia, Lower respiratory infections


  • Cause: infectious (eg bacterial, viral, fungal or parasitic), and non-infectious (eg trauma, foreign bodies, neoplasia) causes.
  • Signs: depend on cause.
  • Diagnosis: hematology and biochemistry, diagnostic imaging, endoscopy, virology, bacterial and fungal cultures, parasitology, cytology and histopathology.
  • Treatment: systemic antibiotic and antifungal medications, nebulization, mucolytics, coupage, correction of underlying predisposing causes (particularly husbandry issues), maintenance at the upper end of the preferred optimum temperature zone.
  • Prognosis: fair to guarded depending on cause. In the case of viral and neoplastic disease, prognosis is often extremely guarded.
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Presenting signs

  • Increased respiratory rate and effort (dyspnea or tachypnea).
  • Lung inflation in chelonia is dependent on movement of the limbs and limb girdles. Observe the synchronous movements of the thoracic limbs especially when assessing respiratory rate and effort in tortoises.
  • Open mouth breathing.
  • Discharge in the oral cavity.
  • Discharge from the glottis.
  • Inflammation of the trachea, seen just inside the glottis.
  • Yawning in snakes.
  • Exaggerated gular movements.
  • Coughing up discharge in lizards and chelonia.
  • Abnormal respiratory noise, particularly wheezing or whistling.
  • Holding the head in an elevated position (snakes).
  • Flotation abnormalities (aquatic turtles).
  • Cyanosis of mucous membranes.
  • Weight loss, lethargy, inappetence.
  • Concurrent upper respiratory disease Upper respiratory tract disease/stomatitis Stomatitis is often seen. Upper respiratory infections may progress to involve the lower respiratory system.
  • Altered behavior. 

Geographic incidence

  • Worldwide.

Public health considerations

  • Mycobacteria spp can cause pneumonia Pneumonia in reptiles. All atypical mycobacterial infections are potentially pathogens in humans and can cause zoonotic disease, with immunocompromised individuals being particularly at risk.
  • Chlamydophila psittaci, Chlamydophila abortus and Chlamydophila pneumoniae have been reported in reptiles with lower respiratory tract disease. These are potentially zoonotic.
  • Salmonella spp have been implicated in cases of respiratory disease in reptiles and may cause zoonotic disease.

Cost considerations

Infectious causes

  • Bacterial:
    • Usually occur secondary to immunosuppression or concurrent disease.
    • May occur secondary to bacteremia, stomatitis Stomatitis or viral infections.
    • Various species implicated, included Pseudomonas spp, Aeromonas spp, Proteus spp, Staphylococcus spp, Salmonella spp and Klebsiella spp.
    • Mycoplasma spp commonly cause respiratory disease, including pneumonia, in chelonia and crocodilians.
  • Viral:
    • Herpes virus Herpes virus infection and iridovirus (Ranavirus spp) infections are important causes of respiratory disease in chelonia.
    • Paramyxovirus, including Sunshine virus in Australian pythons Sunshinevirus infection, and reovirus are important causes of respiratory disease in squamates.
    • Inclusion body disease Inclusion body disease associated with arenavirus infection is an important cause of neuro-respiratory disease in boids.
    • Adenovirus can be associated with pneumonia in crocodilians and snakes.
    • Nidovirus infection is an emerging disease predominantly affecting pythons and leading to respiratory disease and stomatitis.
  • Fungal:
    • Most are opportunistic in the respiratory tract, most are environmental organisms.
    • Various species have been implicated in pneumonia in reptiles, including Aspergillus spp, Candida spp, Penicillium spp and Geotrichum spp.
  • Parasitic:
    • Pentastomids (tongue worms) are worm-like crustacean parasites that affect the lungs and trachea of various reptile species. They have an indirect life cycle requiring an intermediate host. In the lungs, they cause inflammation and often lead to secondary bacterial infections.
    • Lungworms of the genus Rhabdius affect the respiratory tract of snakes, lizards and sea turtles.
    • Lung mites (Entonyssiae) affect snakes.

Non-infectious causes

  • Penetrating injuries to the lungs (often caused by cars, dog bites or lawnmowers in the case of chelonians kept partly outdoors, or from bite wounds by conspecifics in other taxa).
  • Respiratory foreign bodies.
  • Trauma and secondary hemorrhage, contusions, etc.
  • Neoplastic diseases:
    • Primary neoplasia or pulmonary metastasis has been reported sporadically in reptiles.
    • Lymphoma commonly affects the oral cavity and lungs in snakes.
    • Several cases of tracheal chondromas are reported in royal pythons.
  • Pulmonary edema secondary to hepatic or cardiovascular disease.
  • Reductions in tidal volume and subsequent clinical signs of lower respiratory compromise may be seen secondary to organomegaly, ascites, obesity Obesity or pregnancy.
  • Hypovitaminosis A Hypovitaminosis A may cause degeneration of epithelial surfaces of lung faveoli.
  • Urate deposition in the lungs may occur in cases of visceral gout Gout.


Predisposing factors


  • Repties have a poor mucociliary clearance capability and are unable to truly cough due to the lack of a diaphragm.
  • Immunosuppression due to husbandry deficiencies, malnutrition, concurrent disease processes or treatment with corticosteroids.
  • The breeding season is often a time of stress for snakes, particularly when being cooled dramatically, or bred very frequently.
  • Poor hygiene within the vivarium.
  • Excessive humidity within the vivarium.
  • Inadequate ventilation within the vivarium.
  • Poor biosecurity/quarantine practices Quarantine.
  • Failure to carry out routine parasitic or viral screening.
  • Maintaining an open collection.
  • Snake mites: these may act as vectors for the spread of viral diseases.
  • Wild caught animals are predisposed to endoparisitism, including pentastomids and lung worms Chelonia parasitology overview Lizard parasitology overview Snake parasitology overview.
  • Animals kept at high stocking densities, eg farmed chelonia.
  • Respiratory irritants, eg the use of cedar or pine substrates.
  • Smoke inhalation.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hoon-Hanks L L, Layton M L, Ossiboff R J et al (2018) Respiratory disease in ball pythons experimentally infected with ball python nidovirus. Virology 517, 77-87 PubMed.
  • Ebani V V (2017) Domestic reptiles as source of zoonotic bacteria: a mini review. Asian Pac J Tropical Med 10 (8), 723-728 PubMed.
  • Stenglein M D, Jacobson E R, Wozniac E J et al (2014) Ball python Nidovirus: a candidate etiologic agent for severe respiratory disease in python regius. Mbio 5 (5), e01484-14 PubMed.
  • Origgi F (2012) Testudinid herpesviruses: a review. J Herpetol Med Surg 22 (1-2), 42-54 VetMedResource.
  • Schumacher J (2011) Respiratory medicine of reptiles. Vet Clin North Am 14 (2), 207-224 VetMedResource.
  • Myers D A, Wellehan J F Jr & Isaza R (2009) Saccular lung cannulation in a ball python (Python regius) to treat a tracheal obstruction. J Zoo Wildl Med 40 (1), 214-216 PubMed.
  • Drew M L, Phalen D N, Berridge B R et al (1999) Partial tracheal obstruction due to chondromas in ball pythons (Python regius). J Zoo Wildl Med 30 (1), 151-157 PubMed.
  • Diethelm G, Stauber E, Tillson M et al (1996) Tracheal resection and anastomosis for an intratracheal chondroma in a ball python. JAVMA 209 (4), 786-788 PubMed.

Other sources of information

  • Beaufrère H, Summa N & Le K (2016) Respiratory System. In: Current Therapy in Exotic Pet Practice. Eds: Mitchell M A & Tully T N Jr. Elsevier Saunders, USA. pp 76-151.
  • Carpenter J, Klaphake E & Gibbons P (2013) Reptile formulary and laboratory normals. In: Current Therapy in Reptile Medicine and Surgery. Eds: Mader D & Divers S. Elsevier Saunders, USA. pp 382-410.
  • Pare J (2013) Update on Fungal Infections in Reptiles. In: Current Therapy in Reptile Medicine and Surgery. Eds: Mader D & Divers S. Elsevier Saunders, USA. pp 53-56.
  • Schneller P & Pantchev N (2008) Specific Parasitology in Snakes, Lizards and Chelonians. In: Parasitology in Snakes, Lizards and Chelonians a Husbandry Guide. Eds: Schneller P & Pantchev N. Edition Chimaira. pp 38-66.
  • Boyer T (2006) Hypovitaminosis A and Hypervitaminosis A. In: Reptile Medicine and Surgery. 2nd edn. Ed: Mader D. Elsevier Saunders, USA. pp 831-835.
  • Mader D (2006) Gout. In: Reptile Medicine and Surgery. 2nd edn. Elsevier Saunders, USA. pp 793-800.
  • Murray M J (2006) Cardiopulmonary Anatomy and Physiology. In: Reptile Medicine and Surgery. 2nd edn. Ed: Mader D. Elsevier Saunders, USA. pp 124-134.
  • Hernandez-Divers S (2005) Diagnostic Techniques. In: Reptile Medicine and Surgery. 2nd edn. Ed: Mader D. Elsevier Saunders, USA. pp 490-532.

Further Information 


  • British Veterinary Zoological Society (BVZS). Website: www.bvzs.org.
  • Association of Reptilian and Amphibian Veterinarians (ARAV). Website: https://arav.org.