Respiratory infections (RIs) are one of the leading causes of veterinary visits and mortality in captive reptiles. Because reptiles lack a diaphragm and cannot cough effectively, mucus and pathogens accumulate in the lungs more readily than in mammals. Bacterial, viral, fungal, and parasitic organisms can all be involved, but the underlying trigger is almost always a husbandry deficiency that suppresses the immune system.

Root causes

Temperatures below the species-specific preferred optimum zone slow immune function dramatically. Excessive humidity for arid species or insufficient humidity for tropical species damages respiratory tissue. Poor ventilation, dirty substrates, and overcrowding increase pathogen load. Stress from improper handling, cohabitation with incompatible animals, and chronic malnutrition (particularly vitamin A deficiency) are compounding factors.

Symptoms

Early signs include subtle mouth breathing, slightly elevated head posture, mild wheezing, and small bubbles at the nostrils. As infection progresses, mucus becomes visible in the mouth, breathing sounds become audible without a stethoscope, and the reptile may gape frequently. Lethargy, loss of appetite, and weight loss develop. Severe pneumonia causes open-mouth breathing at rest, a stretched-neck posture, and an inability to right itself if turned.

When it becomes an emergency

A reptile that is mouth-breathing at rest, producing excessive mucus, or showing cyanotic (bluish) discoloration of mucous membranes is in respiratory crisis. Snakes that consistently rest with the head elevated or float lopsidedly in water may have unilateral lung consolidation. These presentations require same-day veterinary care.

Veterinary treatment

Diagnosis involves physical examination, radiographs, and possibly a tracheal wash for culture and sensitivity testing. Treatment typically includes systemic antibiotics (often injectable, since oral absorption is unreliable in sick reptiles), nebulization with saline and sometimes antibiotics, fluid therapy, and nutritional support. Antifungal therapy is added when fungal organisms are identified. Treatment courses often last four to six weeks.

Prevention

Maintain species-appropriate temperature gradients with properly functioning thermostats. Monitor and adjust humidity to match the species’ natural habitat. Provide adequate ventilation while avoiding cold drafts. Keep enclosures clean and quarantine new animals for at least 60 to 90 days. Offer a nutritionally complete diet and ensure vitamin A levels are adequate, particularly for herbivorous and insectivorous species.

Veterinary disclaimer: This article is for general education only and does not replace an examination by a licensed reptile veterinarian. If your reptile is mouth-breathing or producing nasal discharge, seek veterinary care promptly.